Difference between revisions of "Book - Handbook of Pathological Anatomy 2.5"

From Embryology
Line 232: Line 232:
  
  
==Section II. Of the Muscles of the Extremities==
+
==Section III. Of the Muscles of the Extremities==
  
 
§ 1 105. The muscles of the extremities form the greater part of these  
 
§ 1 105. The muscles of the extremities form the greater part of these  

Revision as of 13:19, 20 October 2018

Embryology - 11 Aug 2020    Facebook link Pinterest link Twitter link  Expand to Translate  
Google Translate - select your language from the list shown below (this will open a new external page)

العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt    These external translations are automated and may not be accurate. (More? About Translations)

A personal message from Dr Mark Hill (May 2020)  
Mark Hill.jpg
I have decided to take early retirement in September 2020. During the many years online I have received wonderful feedback from many readers, researchers and students interested in human embryology. I especially thank my research collaborators and contributors to the site. The good news is Embryology will remain online and I will continue my association with UNSW Australia. I look forward to updating and including the many exciting new discoveries in Embryology!

Meckel JF. Handbook of Pathological Anatomy (Handbuch der pathologischen Anatomie) Vol. 2. (1812) Leipzig.

Ligaments: I. Trunk | II. Head | III. Extremities   Muscles: I. Trunk | II. Head | III. Extremities   Angiology: I. Heart | II. Body or Aorta Arteries | III. Body Veins| IV. Pulmonary Artery | V. Pulmonary Veins | VI. Lymphatic System | VII. A Comparison of Vascular System   Nervous System: I. Central Nervous System
Online Editor  
Mark Hill.jpg
This historic 1812 textbook by J. F. Meckel, Professor of Anatomy at Halle, was translated firstly from German Into French (with additions and notes) by Prof. A. J. L. Jourdan and G. Breschet. Then translated again from French into English (with notes) by A. Sidney Doane.



Modern Notes: tendon

Musculoskeletal Links: Introduction | mesoderm | somitogenesis | limb | cartilage | bone | bone timeline | bone marrow | shoulder | pelvis | axial skeleton | skull | joint | skeletal muscle | muscle timeline | tendon | diaphragm | Lecture - Musculoskeletal | Lecture Movie | musculoskeletal abnormalities | limb abnormalities | developmental hip dysplasia | cartilage histology | bone histology | Skeletal Muscle Histology | Category:Musculoskeletal
Historic Embryology - Musculoskeletal  
1853 Bone | 1885 Sphenoid | 1902 - Pubo-femoral Region | Spinal Column and Back | Body Segmentation | Cranium | Body Wall, Ribs, and Sternum | Limbs | 1901 - Limbs | 1902 - Arm Development | 1906 Human Embryo Ossification | 1906 Lower limb Nerves and Muscle | 1907 - Muscular System | Skeleton and Limbs | 1908 Vertebra | 1908 Cervical Vertebra | 1909 Mandible | 1910 - Skeleton and Connective Tissues | Muscular System | Coelom and Diaphragm | 1913 Clavicle | 1920 Clavicle | 1921 - External body form | Connective tissues and skeletal | Muscular | Diaphragm | 1929 Rat Somite | 1932 Pelvis | 1940 Synovial Joints | 1943 Human Embryonic, Fetal and Circumnatal Skeleton | 1947 Joints | 1949 Cartilage and Bone | 1957 Chondrification Hands and Feet | 1968 Knee
Historic Disclaimer - information about historic embryology pages 
Mark Hill.jpg
Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

Section II. Of the Muscles of the Head

§ 1095. The muscles of the head comprise those of the skull and those of the face.

The muscles of the skull are the occipito-frontalis, the auricular muscles, and one muscle of the lower jaw.

The muscles of the face are those of the eyes, the nose, the lips, the other muscles of the lower jaw, and the hyoid muscles.

Of these muscles we shall here examine only the occipito-frontalis, and those of the lower jaw, both because the parts which must necessarily be known to understand the descriptions of the others are not yet mentioned, and also because it is more convenient to examine them in connection with the other constituent parts of the organs which they assist to form.


I. OCCIPITOFRONTALIS,

§ 1096. The occipi to- frontalis or epicranial muscle (JVt. epicranius , s. cranii cutaneus , s. occipito frontalis ) is a flat, digastric muscle, situated directly under the skin, to which it is intimately attached, and covers the anterior, upper, and posterior parts of the skull, and also the central and upper part of the face.

Its posterior belly, which is also described as a separate muscle, termed the occipitalis , has an oblong square, or triangular form. It arises by tendinous fibres from the root of the mastoid process, and from the upper occipital ridge of the basilar bone, where it unites with the sterno-cleido-mastoideus and trapezius muscles, soon becomes fleshy, ascends on the squamous portion of the occipital bone, and terminates by a concave edge which unites with the median tendon.

This tendon is called the skull-cap ( galea capitis ), and is formed of very distinct longitudinal fibres. It extends all along the skull to the frontal bone, where it is attached to the anterior belly or the frontalis muscle.

The anterior belly or the frontalis muscle is much more extensive than the posterior. It begins by an upper convex edge, then descends along the squamous portion of the temporal bone, goes straight to its inner part, which is the thickest, and obliquely forward to the outer, which is thinner, and terminates as follows : at its inner part, it is continuous by several slightly tendinous slips with the pyramidalis nasi and the levator labii superioris alÅ“que nasi muscles ; in the region of the inner angle of the eye, it is attached to the nasal process of the upper maxillary bone and to the lower portion of the frontal bone ; finally, at its outer part, it blends with the corrugator supercilii and the orbicularis palpebrarum muscles.

The occipito-frontalis muscle corresponds in situation and attachment to the interspinales muscles of the vertebræ. It resembles one of these muscles which is enlarged, rounded, and divided in its centre, from before backward, into two parts, united by an intermediate tendon.

Considered as a whole, this muscle moves the skin of the top of the head. Its two bellies wrinkle in a transverse direction the skin above them, and extends that near them when they contract from the side of their tendon. Thus the frontal muscle raises that of the upper part of the neck.


II. MUSCLES OF TIIE LOWER MAXILLARY BONE.

§ 1097. The muscles of the lower maxillary bone comprise those which raise it, those which move it to the side, and those which depress it.


MYOLOGY.


109


I. LEVATORS OF THE LOWER JAW.

§ 1098. The lower jaw is moved by three levators, the action of which is to bring it towards the upper jaw, which is fixed. These are the temporalis, the masseter, and the pterygoideus internus muscles.

A. TEMPORALIS.

§ 1099. The temporalis muscle, Temporo-maxillaire, Ch., the largest and strongest of all the muscles of the lower jaw, is broad and triangular. It occupies all the lower region of the central part of the lateral face of the skull, for it fills the temporal fossa, and covers the plain semicircular surface.

It arises by very short tendinous fibres and by a convex edge from the semicircular line which bounds the lower part of the outer face of the frontal bone, from the large wing of the sphenoid bone, from the parietal bone, and the squamous portion of the temporal bone, and by fleshy fibres from the parts of these same bones situated below this line. Its posterior fibres go from above downward and from behind forward, the central are almost perpendicular, the upper go from above downward and from before backward ; all converge to unite in the temporal fossa.

As they leave the circumference the muscle becomes narrower and thicker, and terminates in a short but very strong tendon, which is attached to the coronoid process of the lower maxillary bone.

The entire muscle is covered externally by a tendinous expansion, formed of descending fibres which arise immediately over it, serves for the attachment of its fibres above, is separated below, on its outer face, by a greater or less quantity of fat, and is very loosely united to it in this place by cellular tissue and vessels, and is attached to the posterior edge of the malar bone and also to the upper edge of the zygomatic arch.

This muscle draws the lower jaw forward and upward.


B. MASSETER.

§ 1100. The masseter muscle, Zygomato-maxillaire , Ch. (JVI. masse ter } s. mandibularis externus ), has an oblong square form. Its length exceeds its breadth, and it is formed of fibres which go upward. It covers the outer face of the ascending branch of the lower maxillary bone, and fills the space between the posterior part of the lower edge of this bone and the zygomatic arch.

It is very evidently formed of two layers entirely separate from each other, which differ also in the direction of their fibres, and which may be regarded as two distinct muscles.

The anterior external layer is the longest and strongest, and covers most of the lower. It is formed of fibres which are oblique from above


110


DESCRIPTIVE ANATOMY


downward and from before backward, and become a little narrower from below upward. It arises by short tendinous fibres from the lower edge of the malar bone, and is attached to the lower half of the ascending branch of the lower maxillary bone, as far as its inferior edge and its angle.

The inferior or posterior layer is much smaller and feebler than the preceding ; its form is also square, and it is composed of fibres which go backward. It becomes thicker from below upward, is loose posteriorly, and is covered anteriorly by the preceding layer. It arises by fleshy fibres from the lower edge of the posterior part of the zygomatic arch, and is attached by short tendinous fibres above the upper end of the insertion of the external layer in the centre of the outer face of the ascending branch of the lower maxillary bone.

The two layers unite and draw the lower jaw upward, the external brings it forward, and the internal backward.

C. PTERYGOIDEUS INTERNUS.

§ 1101. The pterygoideus intermis muscle, Grand ptereygo-mariltaire , Ch., an oblong quadrangular muscle, arises by its upper thick edge from all the pterygoid fossa of the pterygoid process of the sphenoid bone, goes obliquely downward and outward and is attached, opposite the preceding, but to a much less extent than it, to the lower part of the inner face of the ascending branch of the lower maxillary bone, as far as the angle.

It draws the jaw upward and inward; but if the muscles of both sides act, the jaw is moved directly upward.

II. PTERYGOIDEUS EXTERNUS.

§ 1102. The lower jaw is moved laterally by a single muscle, the pterygoideus externus muscle, Petit pterygo-maxillaire, Ch., situated between the lower maxillary bone and the pterygoid process. This is the smallest muscle of the lower jaw, and differs from the others in the transverse direction of its fibres. It arises by short tendinous fibres from all the outer face of the outer layer of the middle sphenoid or pterygoid process, then goes directly backward and outward, and is inserted by short tendinous fibres in the inner face of the neck, and of (he condyle of the lower maxillary bone.

It draws the lower jaw from the opposite side, that is inward and forward, when it acts alone : but forward only when it contracts with its synonymous muscle of the other side.


MYOLOGY,


111


III. DIGASTBICUS.


§ 1103. Although several muscles contribute more or less directly to depress the lower jaw,(l) there is however but one appropriated specially to this function ; this is the digastricus muscle, JVLastoidogenien , Ch., ( J\I . biventer maxillÅ“ inferior is), so named because formed of two oblong bellies united by a central tendon.

The posterior longer and stronger belly is more rounded than the other and arises from the mastoid fissure of the temporal bone, and is covered hi this part by the upper end of the sterno-cleido-mastoideus muscle. Leaving this point, it goes downward, forward, and inward, and gradually becomes a thinner oblong median tendon, which is attached by a small tendinous expansion on its anterior extremity to the lateral end of the central piece of the hyoid bone ; so that it is situated between the temporal and hyoid bones.

The anterior belly is shorter and flatter than the posterior, and arises behind the median tendon ; goes forward and inward, and is attached dnectly at the side of the synonymous belly of the opposite side to the centre of the inner lip of the lower edge of the jaw.

This muscle draws the lower jaw downward and backward. If the posterior acts alone, it raises the hyoid bone and draws it backward. If the anterior acts singly, this bone is also raised but earned forward. When the posterior belly contracts behind and the anterior before, it draws the skull and the face, except the lower jaw, backward, and thus by its action on the skull raises the upper jaw, separates it from the lower, and opens the mouth.

§ 1104. A very common anomaly of this muscle consists in the union of the anterior bellies of the two sides with each other and with the pterygoideus externus muscle, by the formation of a larger or smaller fleshy portion. (2) Sometimes too we find between it and the skin a special transverse fasciculus, which is extended between the branches of the lower maxillary bone. (3)

These anomalies are evidently imitations of what is seen in several mammalia, where the anteriör bellies even blend with each other.

More rarely the anterior belly does not extend to the chin, but is attached to the centre of the horizontal branch of the lower maxillary bone, as is also the case in many mammalia, where the single muscle, with which it is provided is also inserted more posteriorly than in man

(1) A Monro, Remarks on the articulation, muscles, arid luxation of the lower jaw, in ihe Edinburgh medical Essays, v ol. i. p. 103-129. — j. C. Platncr, De musculo digastrico maxillœ inferioris, Leipsic, 1737. — Winslow, Observ. par V anatomie comparée sur V usage des muscles digastriques de la mâchoire inférieure dans l'homme , in the Mém. de Paris , anno 1742, p. 236.

(2) G. Meckel, De duplic. monstr., p. 42.

(3) Fleischnrann, in the Erlanger Abhandl., vol. i.


Section III. Of the Muscles of the Extremities

§ 1 105. The muscles of the extremities form the greater part of these sections of the body. Most of them have a more or less elongated form and assume a longitudinal direction, although this is not the direction of their fibres, which go obliquely from one or more edges to the tendons. Very few of them have a transverse direction or one intermediate between it and the preceding : the latter are shorter.

The muscles which follow the longitudinal direction flex and extend the different parts of the limbs ; the transverse and the oblique separate them from each other or turn them on their axes.

The muscles of both extremities are surrounded with general tendinous sheaths ( fascia! aponeuroticœ) and the tendons of the inferior, which are the longest in proportion, and are firmly attached in several places by strong fibrous ligaments to the bones over which they pass.

In regard to situation, arrangement, and number, they correspond perfectly in their essential particulars, and differ only in modifications dependent on the different functions of the two limbs.


CHAPTER I.

MUSCLES OF THE UPPER EXTREMITIES.

§ 1106. The muscles which move the first section of the bones of the upper extremity, or the bones of the shoulder, all come from the bones of the trunk, from which arise also some of those which move the bone of the second section — the humerus. The former are the trapezius, the rhomboidei, and the levator anguli scapulæ ; the others the pectoralis major and the latissimus dorsi muscles, which have already been described (§ 1001).

It is convenient to commence the description of these muscles by that of their common aponeurotic sheath.


ARTICLE FIRST.

OF THE APONEUROTIC SHEATH OF THE UPPER LIMBS.

§ 1107. The muscles of the upper extremities are surrounded by a tendinous envelop called the brachial aponeurosis (fascia brachialis).


MYOLOGY.


113


This arises in very muscular subjects from the deltoid muscle, but sometimes we do not see it except below this muscle. It is always stronger on the fore-arm than on the arm. However, at the posterior part of the anterior and posterior faces it is always much thicker than on the other faces and strengthened by transverse and oblique fibres, which cover the longitudinal fibres externally.

In most of its extent it envelopes the muscles externally only. However, at the lower end of the arm, in the inner angle, there is a triangular slip, the internal and external intermuscular ligament ( L . intermuscular e internum et externum ), which leaves the aponeurosis and goes forward. The external extends from the outer condyle to the upper extremity of the projecting part of the anterior angle ; the internal from the inner condyle to the corresponding point of the inner angle. They extend between the extensors and flexors of the fore-arm and increase their surfaces of attachment.

Two similar but much weaker ligaments are also found in the forearm in a similar situation. They separate the flexors and the extensors, both on the ulnar and radial side ; because they proceed from the inner face of the aponeurosis to the posterior edge of the ulna and of the radius to which they are attached.

Near the lower end of the fore-arm, the transverse fibres disappear, or at least become evidently thinner ; but they again accumulate on the end of its posterior face and on the back of the thumb, become much more thick than high, and give rise in this place to the dorsal ligament of the carpus ( Lig . carpi dorsale , s. armillare ).

This ligament extends from the transverse process of the radius to the small head of the ulna, the pisiform, and the tuberosity of the fifth metacarpal bones. It is formed at its upper part, which is the weakest, of transverse fibres, which descend from the ulna to the radius, and at the lower part of fibres, which go backward and downward from the radius, and consequently partially cross the preceding.

Under it pass the tendons of the abductor magnus and extensor pollicis, the radiales externi, the extensor digitorum communis, the extensor indicis proprius, the extensor minimi digiti proprius, and the ulnaris externus muscles. Their passage is facilitated by the partitions which descend from the inner face of the ligament to the asperities on the ends of the bones of the fore-arm and divide it into six parts.

The first, the anterior,, extends from the anterior edge of the lower end of the radius to the first asperity on the back of this bone, and contains the tendons of the abductor pollicis longus and of the extensor pollicis brevis muscles.

Through the second, which is larger and which extends from the first dorsal asperity to the second, pass the tendons of the two radial© externi muscles.

The third, a little oblique forward and downward, extends from tin second to the third dorsal asperity of the radius, to the posterior edge

Vol. IT. 15


114


DESCRIPTIVE ANATOMY.


of its lower extremity, and lodges the tendon of the extensor pollids longue muscle.

The fourth, the largest, extends from the third dorsal eminence to the posterior edge of the radius, and receives the tendons of the extensor digitorum communis and extensor proprius indicis muscles.

The fifth, the smallest, is comprised between the radius and the anterior edge of the small head of the ulna ; it receives the tendon of the extensor minimi digiti proprius muscle.

Finally, the sixth, which extends from the posterior edge of the small head of the ulna to its styloid process, embiaces the tendon of the ulnaris externus muscle.

The lower edge of this ligament, which should be regarded not as a separate ligament but only as the development of the brachial aponeurosis, is uninterruptedly continuous with the aponeurosis of the back of the hand, which gives a loose common envelop to the tendons of the extensor muscles, blends with the oblique tendinous fibres by which the tendons of the extensors of the fingers are retained in place, and concurs to form them.

The brachial fascia is also strengthened at the lower part of the anterior face of the fore-arm and on the palmar side of the carpus.

The upper part of this portion, which is the feeblest and which extends from the anterior edge of the radius to the pisiform bone, forms the common palmar ligament of the carpus ( Lig . carpi velar e commune). It unites at its ends with the dorsal ligament. Under it pass the tendons of the flexors of the fingers, and in a special sheath that of the radialis internus.

The lower part, which is much stronger, forms the proper palmar ligament of the carpus {Lig- carpi volare proprium). This ligament is formed by transverse and oblique fibres. Above, it blends in great part with the preceding. Below, it strengthens the palmar aponeurosis. Its two edges arise from the palmar eminences of the carpus, which are formed on the radial side by the trapezium and the pyramidal bones and on the ulnar side by the pisiform and unciform bones.

ARTICLE SECOND.

MUSCLES OF THE SHOULDER.

§ 1108. The muscles of the shoulder, which surround the scapula and which extend from this bone and also from the clavicle to the humerus, are the deltoides, the supraspinatus, the infraspinatus, the teres major, the subscapularis, the teres minor, and the coraco-brachialis

muscles.

I. deltoïdes, or the extensor of the arm.

§1109. The deltoides muscle, Sus-acromio-humeral, Ch. {M. deltoïdes , levator , attollens humeri), is a very strong muscle, which occupies


3IYOLOGY.


115


the upper and anterior part of the region of the shoulder. It arises by its upper longest and concave edge from the anterior edge of the scapular end of the clavicle, from the anterior edge of the acromion process, and from the lower edge of all the spine of the scapula at its anterior part, by fibres almost entirely fleshy or which at least have very short tendons, and by very long tendinous fibres at its posterior.

After leaving this point, the muscle gradually becomes thicker, goe3 downward, and terminates by a fleshy summit externally, but possessing within a very long tendon, which is attached directly below the tendon of the pectoralis major muscle, at the posterior end of the external linea aspera, which arises from the outer tubercle of the humerus and at the central part of the outer face of this bone, which presents in this place a triangular impression.

These fibres converge from above downward ; so that the central are straight, the anterior oblique from before backward, and the posterior from behind forward.

In examining this muscle more attentively, we recognize that it is composed of two orders of triangular fasciculi. The first order contains four fasciculi, which are larger than the others and the bases of which are turned upward and their summits downward. Between are the three smaller fasciculi of the second order, which are broader below than above but the two ends of which are a little narrower than the central part.

Below the upper edge of this muscle, between it and the capsular ligament, we find a considerable mucous bursa, which corresponds usually to the acromion, extends between this last process and the proper anterior ligament of the shoulder, and sometimes divides into two bursæ, one of which is situated near the coracoid process.

The deltoid muscle raises the arm and separates it. from the side of the body.

§ 1110. A remarkable analogy -with the structure of the mammalia is the existence of a posterior slip, entirely distinct from the rest of the muscle, which we have found several times. This slip arises from the tendinous expansion of the infraspinatus muscle (§ 1112), and from the centre of the inner edge of the scapula, by a broad and thin tendon, and is attached to the tendon of the deltoides. In most mammalia, in fact, the deltoides divides into a clavicular and a scapular portion and the latter is subdivided into an acromial and a spinous portion.

We more frequently find the posterior part of the muscle simply separated from the anterior. We ought also to place among these anomalies the existence of a head, which goes from the anterior edge of the scapula to the deltoides,(l) and which is still more analogous â– with a part of the deltoides in birds.


(1) Albinus, p. 422.


116


t» ESi'RÏ PTT VE ANATOMY.


II. ROTATORS OUTWARDLY.

I. SUPRASPINATUS.

§ 1111. The supraspinatus muscle, Petit susse upvlo-trochitcriev Ch., is a triangular muscle which fills the supraspinal fossa, and is formed of fibres which converge from behind forward, from below upward, and from within outward. At first it is rather thick, but gradually becomes thinner. It arises from all the supraspinal fossa, from that part of the posterior edge of the scapula situated above the spine, and from the posterior part of the upper edge and also from the upper face of this spine. It changes under the acromion process, directly below the large proper ligaments of the scapula, into a short and strong tendon, which, passing below the capsular ligament of the scapulo-humeral articulation, which it contributes to strengthen, goes to attach itself to the upper and inner part of the outer tubercle of the humerus.

This muscle turns the arm outward and raises it,

II. INFRASPINATUS.

§ 1112 . The infraspinatus muscle, Grand susscapido-trochiterien , Ch., arises from all the infraspinal fossa of the scapula, except its lower part. It goes outward and forward, so that its upper fibres are transverse, and the lower become more oblique forward and upward the lower they are. Its thickness gradually increases as it proceeds outwardly and it terminates in a strong tendon, which extends farther on the posterior than on the anterior face. This tendon adheres to the capsular ligament of the shoulder which it strengthens, blends above with that of the preceding muscle, and is attached to the central part of the outer tubercle of the humerus.

We find a large mucous bursa between the scapula and this tendon.

This muscle draws the humerus backward and downward, and rotates it from within outward.

III. TERES MINOR.

§ 1113. The teres minor muscle, Plus petit susscapulodrochiterien, Ch. is quadrangular, and is scarcely distinguished from the preceding. It arises from the central part of the posterior lip of the anterior edge of the scapula, and goes directly before the lower and anterior edge of the infraspinatus muscle forward, outward, and downward, where, gradually becoming narrower but thicker, it terminates by a short and strong tendon at the lower part of rhe outer tubercle of the humerus, and at the outer ridge of the humerus which descends from this tubercle.

It acts like the preceding, but it draws the humerus more outward

MYOLOGY.


117


HI. ROTATORS INWARD.

SUB-SCAPÃœLARIS.

§ 1114. The subscapularis muscle, sous-scapulo-trochinien , Ch., the strongest of the two muscles which turns the humerus on its axis inward, occupies all the lower face of the scapula. Its upper fibres descend obliquely outward and forward, the central are transverse, and the inferior are very oblique from behind forward and from within outward. It gradually contracts to a considerable degree, passes behind the upper end of the coraco-brachialis, and the shoit head of the biceps muscle, and terminates in a short, flat, and thick tendon, which is attached to all the circumference of the inner tubercle of the humerus.

Its structure is very complex, and we may reduce it to two orders of fasciculi which are more or less evidently distinct. The first, commonly five in number, arise by a tendinous summit along the inner lip of the posterior edge, and the asperities which are found on the anterior face of the scapula. The lower, which is also the strongest, forms the lower and outer part of the muscle. All progressively enlarge, and are attached to the upper tendon.

We find the second layer between them ; this also is formed of five fasciculi, of which the upper likewise forms the upper part of the muscle. These fasciculi are generally stronger and broader externally, and pointed inwardly. They come from the spaces between the eminences, whence the former arise.

These two layers however interlace more than once, and we cannot insulate them without cutting their fibres. The third layer, which is described in most works on anatomy, does not in fact exist.

This muscle has two mucous bursæ. The larger is sometimes united with the capsular ligament of the scapulo-humeral articulation, and is situated on the neck, and at the base of the coracoid process of the scapula. The smaller, which does not always exist, is situated much lower and further forward, between the capsular ligament and the tendon of the muscle.

The subscapularis muscle draws the arm towards the trunk, turns it on its axis from without inward, and depresses it when it is raised. If the arm is fixed it can carry the scapula outward.

rr. TERES MAJOR.

§ 1115. The teres major muscle, Scapulo-humeral , Ch. (AÏ. teres , s. rotundas major, s. déprimons hmnerum rotundas) arises from the lower and triangular part of the outer face of the scapula, and from the posterior lip of the anterior edge, where it usually adheres to the subscapularis and teres minor muscles ; but it soon leaves these two muscles and ascends, always much less obliquely than the teres minor, from which


lis


DESCRIPTIVE ANVTOMY.


it is separated by the long portion of the biceps, between the latter and the coraco-brachialis, approximates the humerus, and is attached by rather a short, broad, but thin tendon, to the inner rough line, directly behind and a little below the latissimus dorsi.

Its form is the same as that of the teres minor, but it is at least twice as large as that muscle.

We find below and forward, between its tendon, the latissimus dorsi muscle, and the humerus, a small mucous bursa, and beside these, we also find one or more in its anterior tendon where it divides.

This muscle draws the humerus backward, downward, and inward ; when the arm is turned outward, it brings it a little inward.

§ 1116. It is often united with the posterior part of the latissimus dorsi muscle by a large fasciculus which leaves its posterior extremity.

IV. COKACO BHACHIALIS.

§ 1117. The coraco-brachialis muscle, Coraco-humeral , Ch. (M. coraco-brachialis , s. coracoideus , s. perforatus Casserii) is formed like an oblong triangle. United above, rather intimately, and to some extent, to the origin of the short portion of the biceps flexor muscle (§ 1120), it arises from the coracoid process farther forward than the latter. It, is tendinous before, in most of its length, and fleshy behind. In quitting the short portion of the biceps muscle it goes inward, becomes thicker at its central part, but contracts much at its lower end, and is attached, partly fleshy, partly tendinous, to the middle region of the inner face of the humerus.

The musculo-culaneous nerve generally perforates it in its centre. Its lower part often blends with the upper end of the brachialis internus muscle, a curious fact, as it adds a new feature to the analogy between the flexors of the fore-arm and those of the leg. We find one imperfect bursa, and sometimes two, between its upper tendon, that of the short portion of the biceps muscle, and the capsular ligament of the scapulo-humeral articulation.

This muscle approximates the humerus and the scapula to each other, carries the arm to the side of the bodjq and rolls it a little outward, when it is turned inward.

Sometimes, instead of a simple perforation, it presents a real fissure, which is often confined to its lower part, and sometimes exists its whole length, so that the tendons are separated although the musculocutaneous nerve passes constantly between the two portions. This arrangement establishes a striking similarity with the structure of the apes.


MYOLOGY.


119


ARTICLE THIRD.

MUSCLES OF THE ARM.

§ 1118. The muscles found on the humerus arise partly from this hone, others from the scapula, axrd are attached to the bones of the fore-arm. Theyare the triceps extensor, the biceps flexor, and the brachialis intemus ; the first is situated at the posterior and outer part of the arm ; the other two are placed on its anterior and inner face.


I. TRICEPS EXTENSOR,

§ 1119. The triceps extensor muscle, Scapulo-olecranien , Ch. (JVI. triceps brachii , cubiti , s. brachieus externus , s. posterior) occupies most of the posterior face of the humerus, and extends from the scapula to the olecranon process.

The long or the posterior head ( caput longum, cmconœus longus) arises. by a short, flat, and thick tendon, directly before the anterior insertion of the teres minor muscle, from the upper end of the anterior edge of the scapula, and goes from above downward, gradually increasing in thickness. The tendon descends very low on its inner face. Its lower tendon extends in all its lower half along the inner part of its inner face, and the fleshy fibres are inserted in it obliquely. Its form is elongated.

The large head, or the outer head, ( caput externum, s. magnum, unconcern magnus, s. externus) arises above by a thin extremity which terminates by a convex edge, and presents very short tendinous fibres. This end is attached, directly below the insertion of the teres minor muscle, at the upper part of the posterior face of the humerus. The fleshy fibres come also from all the anterior edge of the bone. This head descends as far as the outer condyle, by a short tendon, which is oblique from above downward, from before backward, and from without inward, unites backward and inward to the lower tendon of the long head. In all its lower portion its inner and posterior pari is covered by the common lower tendon of the brachialis internus muscle Its form is that of an elongated rhomboid, its breadth exceeds its thickness.

The short or internal head arises, directly below the upper extremity of the preceding, from most of the posterior face of the humerus, and descends along the inner edge of the bone to near the inner condyle, rests, by its posterior and inner edge, upon the tendons of the teres major and coraco-brachialis muscles, and also the inner edge of the brachialis internus. Its fibres go obliquely downward and outward ; they are attached to the lower tendon of the long head in all the lower part of the short head.


120


DESCRIPTIVE ANATOMY.


The common lower tendon of these three heads, which covers them outwardly at their lower part, is not destitute of fleshy fibres except in a very small portion of its extent below, and is inserted in the upper broad edge of the posterior face of the olecranon process of the ulna.

We find a considerable mucous bursa between this tendon and the olecranon process, besides which we sometimes find two smaller ones on each side. We less commonly see another, also smaller, above.

This muscle extends the articulation of the elbow and usually moves the fore-arm ; but it can also move the arm when the fore-arm is fixed. The long head brings the scapula towards the humerus, and draws the latter inward and backward.


II. BICEPS FLEXOR.

§ 1120. The biceps flexor muscle, Scapulo-radial , Ch. ( flexor antibrachii biceps, s. radialis, s. biceps internus ), is a very long muscle, situated on the anterior and the outside of the arm, and extends its whole length. Its two heads are separated above in almost all the muscle, and extend from the scapula, whence they arise, to the upper extremity of the radius.

The internal, posterior, or short head ( caput breve), called also the coraco-brachialis muscle, from one of its attachments, is not only shorter but also thinner than the long head. It arises from the coracoid process by a short, flat, and narrow tendon, which it has in common with the coraco-brachialis muscle, more forward and outward than the latter, proceeds on its outside a little obliquely from within outward, covers below the inner and upper part of the brachialis internus muscle, and lower down becomes a tendon, which is first seen on its external face, on the side corresponding to the long head. This tendon, which unites to that of the last, is attached to the tuberosity of the radius.

Tire long head ( caput longum , s. M. glcno-radialis ) arises by a long, thin, and flat tendon from the centre of the upper part of the edge of the glenoid cavity of the scapula. This tendon is inclosed in a special fold of the capside of the scapulo-humeral articulation, which answers as a mucous sheath, passes upon the head of the humerus, and is situated in the groove between the two tuberosities of this bone, where it is retained by the fibres of the fibrous ligament of the shoulder-joint, and on the anterior extremity of which the mucous sheath ceases. It thus comes to the anterior and outer side of the arm, where it soon continues with its fleshy belly but deeper than the tendon of the short head. This latter descends above, along the anterior and external edge of the triceps extensor muscle ; below, before the central part of yhe brachiahs internus muscle : at its lower extremity it is attached on one side, that is by its internal face, to the tendon of the short head ; on the other to a peculiar tendon contained within it, and which when entirely destitute of fleshy fibres is united with that of the first head, being inserted at the same place with it.


MYOLOGY.


121


We find a large mucous bursa between the lower tendon, that of the supinator brevis and the tuberosity of the radius, to which sometimes a smaller is added, situated on the outer face of the tendon.

The principal use of this muscle is to flex the articulation of the elbow. It also turns the fore-arm backward, contributes to draw it inward when it is extended, and depresses the scapula toward the humerus.

§ 1121. The biceps flexor muscle is one of those muscles most subject to variation, and presents the most singular anomalies.

The least considerable anomaly is where the two heads arise much lower than usual, so that they are only united by the inferior tendon.(l)

A greater anomaly, which is not rare, is when a third head exists, which is usually smaller than the other two and which arises near the centre of the internal face of the humerus, (2) more rarely from only the brachialis internus muscle, (3) although it is often blended with it. Sometimes also it is united with the coraco-brachialis muscle. This anomaly is very remarkable, as it is a repetition of the small head, which properly belongs to the biceps femoris muscle, and because its union with the coraco-brachialis muscle makes the number of the long flexors of the fore-arm equal to those of the long flexors of the leg. At the same time it approximates man to animals ; since in birds the long flexor of the fore-arm presents a second smaller head, which arises from the lower tuberosity of the humerus ; while in apes the brachialis internus muscle extends much higher.

The number of heads of this muscle sometimes increases still more, so that we number five ; but these are not inserted in one common inferior tendon. (4) At the side of the third which is most usually met with we sometimes find a fourth, and along the tendon of the short head a fifth, which unite and are attached to the radius below the usual tendon ; in this case, consequently, there were in fact three flexors, as is always found in birds.

III. BRACHIALIS INTERNUS.

§ 1122. The brachialis internus muscle, Humero-cubital, Ch. (AT. flexor cubitalis ulnaris , s. brachieus intermis ), a broader and thicker muscle, especially at its posterior part, which entirely covers the inferior portion of the internal and anterior faces of the humerus, arises by an external and an internal slip, the former being higher, from the external and internal faces of the humerus above its centre. These two slips surround the lower extremity of the deltoides muscle ; the internal extends to the coraco-brachialis and the external to the upper

(1) Weitbrecht, Comment. Petrop., 1731. — Albinus, loc.cit. — Rudolphi, in Gant~er, 6. — We have seen it several times but always on one side.

(2) Albinus, loc. cit., p. 43S, 439. — Mayer, loc. cit.

(3) Kelch, loc. cit., p. 35.

(4) Pietsch, in Roux Journal de Med., vol. xxxi. p. 245.

Vol.II. 16 •


122


DESCRIPTIVE ANATOMY.


extremity of the large head of the triceps extensor muscle. Its anterior edge descends along the external edge of the humerus, and the posterior along the internal edge of this bone to the part where it suddenly enlarges.

Its fibres are attached to a strong rounded inferior tendon, which reascends on the anterior face of the muscle almost to its centre. This tendon is inserted in the tuberosity of the ulna.

Between the tendon of the brachialis internus, that of the biceps flexor cubiti, the supinator brevis muscle, and the capsular ligament, we find a mucous bursa, which is not however constant.

This muscle flexes the articulation of the elbow.

§ 1123. We sometimes find at the side of it, but more forward and outward, a second brachialis internus muscle, which is smaller and which is an exact repetition of it as respects its attachments, the inferior tendon of which is inserted deeper than that of the other, and which even presents a rudiment of the preceding muscle, which we said belonged to birds. The first degree of this anomaly is the separation of the posterior from the anterior part of the muscle, which not unfrequently occurs. This division of the brachialis internus muscle into two parts is also worthy of remark, as it assimilates this muscle to the flexors of the leg. Its abnormal union with the biceps flexor by a muscular slip (§ 1121) is on the contrary the first index of the formation of a third head to the latter (§ 1121).

The anomalies of the brachialis internus, the biceps flexor, and the coraco-brachialis muscles (§ 1116), considered collectively, seem to be so many efforts by which nature endeavors to establish a perfect resemblance between the upper and lower extremities. They are generally found singly ; but if we suppose them united, we have an arrangement perfectly similar to that of the lower extremities.

The coraco-brachialis and brachialis internus muscles, divided into two portions and often united with each other, evidently represent the semimembranosus and the semitendinosus muscles. The muscular band which goes from the brachialis internus to the lower part of the biceps flexor muscle, united with the unusually deep division of the latter, may be considered as tending to insulate the two heads and to form a second flexor of the ulna, even as the tibia is flexed by two distinct muscles.


ARTICLE FOURTH.

MUSCLES OF THE FORE-ARM.

§ 1124. The muscular mass of the fore-arm is formed of those muscles which move the bones upon each other or on the humerus, by the muscles which act on the carpus, and by the long muscles of the fingers.

The motions of the bones of the fore-arm on each other, or pronation and supination, are performed by four muscles, the supinator longus


MYOLOGY.


123


and the supinator brevis, the pronator teres and the pronator quadratus, all of which except the first are situated deeper than the other muscles of the fore-arm.

The two bones of the fore-arm are moved on the humerus by one muscle, the anconeus.

Five muscles move the carpus ; the extensor carpi radialis longus and the extensor carpi radialis brevis extend it ; it is flexed by the flexor carpi ulnaris and the flexor carpi radialis muscles ; the extensor carpi ulnaris draws it backward.

The fingers are extended by the extensor digitorum communis, the extensor pollicis longus and brevis, the extensor indicis proprius, and the extensor minimi digit i proprius ; they are flexed by the flexor sublimis, the flexor profundus, and the flexor pollicis longus.

These different muscles succeed each other in the following order, when we commence their description at the radial edge and follow the external face of the fore-arm to the ulnar edge and return from this to the radial edge along the internal face of the arm.

I. MUSCLES OF THE INTERNAL FACE OF THE FORE-ARM.

I. SUPINATOR LONGUS.

§ 1 1 25. The supinator longus muscle, Humero-sus-radial , Ch.,is a long muscle, which arises by short tendinous fibres from the inferior part of the anterior edge of the humerus, where it unites with the large head of the triceps extensor muscle. It goes downward and passes on the inferior and external part of the brachialis internus, which it covers, and reaches the fore-arm along and before the inferior extremity of this muscle ; it goes on the radial edge of the fore-arm and is changed high up into a long and thin tendon, which covers above only the internal face, and is finally attached to the anterior face of the internal edge of the radius, a short distance above its inferior face. It turns the radius backward and inward, consequently carries the hand to the state of supination, and flexes the fore-arm.

II. EXTENSOR CARPI RADIALIS LONGUS.

§ 1126. The extensor carpi radialis longus muscle, Humero-susmetacarpien , Ch., resembles the preceding and appears at first view to be a part of it. It arises from the lowest part of the outer edge of the humerus, descends to the outer condyle, passes on the outer part of the articular edge of the humerus, and on the head of the radius ; in its course it becomes first thicker, afterward narrower, and terminates at the same place as the preceding in a tendon, at first rather broad, flattened, and loose to a much greater distance, which descends in the same direction along the radius and enters below into the anterior groove of the outer face of the lower extremity of the radius under the posterior ligament of the carpus, thus arrives at the carpus and is attached to


124


DESCRIPTIVE ANATOMY


the anterior part of the posterior face of the base of the second metacarpal bone.

The lower tendon is surrounded with a mucous sheath where it passes over the lower extremity of the radius. We also find a small bursa at its insertion in the root of the second metacarpal bone.

This muscle extends the hand and draws it a little toward the radial side of the fore-arm ; it also serves to execute the motion of pronation toa certain extent and flexes the articulation of the elbow.

§ 1127. Sometimes a smaller and feebler muscle is detached from its lower edge, which succeeds the extensor carpi radialis brevis muscle and is attached a little above it to the root of the third metacarpal bone.(l)

III. EXTENSOR CARPI RADIALIS BREVIS.

§1128. The extensor carpi radialis brevis muscle, Epicondylo-susmétacarpien , Ch., is very similar to the preceding, but is smaller. Its upper tendon, which is very strong, exists nearly the whole length of its posterior face. It arises from the anterior face of the outer condyle of the humerus, and is attached, below the middle of the fore-arm, by an elongated, flat, but narrow tendon, the upper part of which covers the lower part of the outside of the muscle. This tendon is inserted in the outer face of the base of the third metacarpal bone, and slightly also in that of the second. There is a small bursa between it and the third metacarpal bone.

This muscle acts in the same manner as the preceding.

§ 1129. It is sometimes entirely deficient, (2) as in several mammalia, where we never find but one extensor radialis muscle : the first degree of this formation is the complete union of the second radialis muscle, of which several instances are known. Sometimes its tendon divides into two slips, which are attached to the third metacarpal bone only, or one is inserted into this bone, and the other into the next ; even as in the mammalia, which have only one radialis muscle, the tendon divides into two slips.

Besides the bursæ already mentioned, the tendons of the two muscles are surrounded by two common sheaths, the upper of which is situated above the lower end of the radius, while the lower is placed at a short distance from it on this extremity, and on the upper range of the carpal bones.


IV. EXTENSOR DIGITOnUM COMMUNIS.

§ 1130. The extensor digitorum communis muscle, Epicondylo-sttsphalangettien commun , Ch., commences by a strong tendon, which

(1) Albinus, Inc. cit., p. 448.

(2) J. G. Salzmann, Diss. sist. rdurium pedis musculorum defectum, Strasburg', 1734, p. 11.


MYOLOGY.


125


extends on the upper part of the external face of its belly. It arises from the lower and back part of the outer condyle of the humerus, directly under and behind the radialis externus brevis muscle, with which it is intimately connected for several inches. Near the centre of the fore-arm it separates into three bellies, the posterior of which also divides a little farther in two others, so that the whole number of these bellies is four ; these are inserted into as many elongated and flat tendons, of which the second is usually the strongest, the third smaller than the first, and the fourth is the weakest.

All these tendons pass under the posterior ligament of the carpus, between it and the outer face of the lower end of the radius. They become broader and thinner on the back of the hand, partially separate, especially near the anterior end of the metacarpus, and are again united by strong oblique intermediate tendons of various breadths. They go to the second, third, fourth and fifth fingers, and contract on the articulation of the metacarpus with the phalanges ; but in this place they give off on each side fibres, which go downward ; farther on they again enlarge, and are blended on each side with the tendons of tho interosseous muscles. On the first joint of the phalanges they divide into a central and two lateral portions, which are much longer ; the central tendon, having strengthened the dorsal face of the capsular ligament, is attached to the upper edge of the base of the second phalanx ; the other two are united forward, and are inserted in the upper part of the back of the third phalanx.

At the lower end of the fore-arm, of the carpus and metacarpus, the tendons of this muscle have a mucous sheath, which is single above, but divides on the carpus into three branches, each of which goes with its tendon to the base of the first phalanx.

This muscle extends the second, third, fourth, and usually the fifth finger also.

§ 1131. Sometimes its three bellies are separated high up, and even at their origin. ( 1 ) Sometimes it divides into four tendons ; the fourth goes to the little finger, and unites to its proper extensor. This fourth tendon sometimes divides on the back of the hand into two parts ; the outer joins the tendon of the extensor minimi digiti proprius muscle, and the inner again divides into two portions, one of which unites to the tendon of the fourth finger, and the other to that of the fifth. (2) In some subjects the third and fourth tendons go to the third finger. In this case the muscle itself often divides into two bellies, each of which has two tendons. (3)

These divisions of the fleshy part of the muscle are curious, being similar in one respect to the extensors of the toes and also to the flexors of the fingers, which are both double.

(1) Albinus, loc. cit., p. 452. — Brugnone, loc. cit., p. 167.

(2) Albinus, loc. cit.

(3) Brugnone, loc. cit.


126


DESCRIPTIVE ANATOMV.


V. EXTENSOR MINIMI DIGITI PROPRIUS.

§ 1132. The extensor minimi digiti proprius muscle, Epicoudytosus-phalangetlien du petit doigt , Ch., is slender, elongated, and thin. It arises bj two tendinous heads from the outer part of the head of the radius, from the part of the capsular ligament surrounding this head, and from the upper end of the anterior edge of the ulna. It descends behind the preceding, with which it is closely united for some distance, and near the lower end of the fore-arm becomes a thin tendon, which passes below the posterior ligament of the carpus in a special groove, enlarges along the metacarpal bone of the fifth finger, unites inward with the fourth tendon of the preceding muscle, and is attached to the upper face of the head of the third phalanx of the little finger.

Its tendon is surrounded from the lower part of the fore-arm to the centre of the fifth metacarpal bone by a sheath, which is single above, but below divides like the tendon into two parts.

This muscle extends the little finger.

§ 1133. It is sometimes deficient, (1) and then it is generally replaced by a tendon of the extensor digitorum communis muscle. In other cases, on the contrary, its tendon divides into two slips, one of which goes to the fourth finger, an arrangement worthy of remark because of its analogy with several mammalia.

VI. EXTENSOR CARPI ULNARIS.

§ 1134. The extensor carpi ulnaris muscle, Cubito-sus-metacarpien, Ch. (M. ulnaris externus , s. extensor manus ulnaris ), arises by two tendinous slips, of which the smaller and shorter is situated at the side of the extensor digitorum communis, and comes from the posterior and lower part of the external condyle of the humerus, and the longer arises from the upper part of the anterior face of the tubercle of the ulna. These two. slips soon unite in a considerable belly. The latter is tendinous at its inner and outer faces, and adheres in a considerable extent to the extensor proprius minimi digiti muscle, descends along the outer face of the ulna, from which it receives some fibres, and becomes, near the lower third of the fore-arm, a strong tendon, which, passing across a particular portion of the dorsal ligament of the carpus, comes on the back of the hand, where it is attached to the tubercle of the metacarpal bone of the fifth finger. There is but one mucous bursa between its upper extremity and the head of the radius.

This muscle extends the hand and draws it backward toward the posterior edge of the fore -arm.

§ 1135. A tendon of greater or less extent is often detached to go to the fifth finger, and at the base of the first phalanx unites with that of its proper extensor.

(1) Brugnone, p. 167. — Wc have known two instances where it was deficient.


MYOLOGY,


127


VII. ANCONÅ’US.

§ 1136. The anconÅ“us muscle, Epicondylo-cubiial, Ch. (J\I. anconÅ“us , s. anconÅ“us quartus), is a triangular muscle and mostly covered by the upper extremity of the preceding ; it arises by a short and strong tendon from the i nner part of the outer condyle of the humerus, descends toward the ulna, and is attached by a broad fleshy surface to the upper part of the anterior face of this bone. Its upper straight edge usually blends with the outer belly of the triceps extensor muscle.

This muscle extends the fore-arm, also turns the radius backward, so that it assists in supination.

VIII. SUPINATOR BREVIS.

§ 1137 . The supinator brevis muscle, Epicondylo-radia! , Ch., is triangular ; its base looks upward, and its apex downward. It arises from the upper part of the anterior face of the ulna, and is tendinous outwardly and fleshy inwardly. Its upper fibres are transverse and the lower oblique. It goes downward and forward, turns on the upper part of the radius, and is attached by a broad fleshy edge to the anterior part of the capsule of the ulna, and also to the upper part of the anterior and inner faces of the radius as far as its posterior edge. It turns the hand and the radius on their axes backward and outward.

§ 1138. The upper part of this muscle often separates from the lower sooner than usual, and differs from it in the direction of its fibres, is separated from it by the radial nerve, and is attached to the radius without being connected with it. This anomaly leads to that in which two small supinator muscles exist ; the upper extending from the outer condyle of the- humerus to the anterior edge of the upper end of the radius, while the internal goes from the head of the radius to its centre. (1) Probably the second variety may be considered as an index of the formation peculiar to apes, in which three supinators exist. (2)


IX. ABDUCTOR POLLICIS LONGUS.

§ 1139 . The abductor pollicis longus muscle, Cubito-sus-métacarpien du pouce , Ch., is a considerable muscle inserted, by very short tendinous fibres, directly below the anconeus and the supinator brevis, to the second fifth of the anterior edge of the ulna, to the outer face of the interosseous ligament, and to the central part of the outer face of the radius. It descends along the last, passes below on the anterior face of the radius, and there becomes a strong tendon, which passes through a particular division of the dorsal ligament of the carpus. This tendon

(1) Sandifort, Hist. muse. p. 93. — Brugnone, loc.cit. p. 163.

(2) We have found at least in the Simia apella two long- supinators, situated at the side of each other.


128


DESCRIPTIVE ANATOMY.


generally divides into two or three slips : the strongest, which is also the most anterior, is attached to the radial edge of the base of the first metacarpal bone ; the other two blend with the posterior extremity of the antagonist muscle of the thumb.

The tendon near its upper extremity is surrounded by a large, oblong, and rounded mucous sheath.

This muscle separates the thumb from the fingers, and moves it toward the radius.

§ 1140. It is often more or less divided into two bellies, each of which terminates by a tendon, and the lower is usually larger than the upper. The tendons of these two bellies are often divided, and sometimes unite ; sometimes they are attached to the first bone of the metacarpus and to the trapezium.(l)

We more rarely find a digastric abductor of the thumb, which arises from the outer condyle of the humerus, and is inserted into the base of the first phalanx of the thumb.

X. EXTENSOR POLLICIS BREVIS.

§ 1141. The extensor pollicis brevis muscle, Cubito-sus-phalangien du pouce , Ch., is a very small muscle, situated below the preceding, and adheres intimately to its inferior edge. It arises from the outer face of the interosseous ligament and from the radius, and becomes a very thin tendon, which passes through the dorsal ligament of the carpus in the same groove with the abductor pollicis longus, then goes on the back of its metacarpal bone, becomes broader, and is attached to the centre of the upper edge of the base of its fjrst phalanx.

This muscle extends the thumb, and at the same time removes it from the other fingers.

§ 1 142. A small tendon sometimes arises from the anterior extremity of its tendon, which blends with that of the next muscle.

Sometimes this muscle does not exist as a distinct muscle, and forms only the lower part of the abductor pollicis longus muscle.

XI. EXTENSOR POLLICIS LONGUS.

§ 1143. The extensor pollicis longus muscle, Cubito-sus-phalangettien du pouce , Ch. (J\I. extensor pollicis major s. longus ), is much stronger than the preceding, and covers its upper part ; it arises, a little below the abductor magnus, and directly below its upper extremity, above from the outer face and below from the anterior edge of the ulna, and from the adjacent part of the external face of the interosseous ligament. It soon becomes a long tendon, which passes through the second groove of the dorsal ligament of the carpus, goes forward at the side of the preceding, but much more inwardly, partially covers it, and


(1) Fleischmann, in the Erlanger Abhand ., vol. i. p. 28.


MYOLOGY.


129


is attached to the base of the second phalanx of the thumb, in the same manner as the tendon of the extensor digitorum communis is ; but it does not divide.

Its tendon has two mucous sheaths : the upper and larger is situated at the lower part of the fore-arm, and extends to the carpus ; the inferior is smaller, and is placed on the carpus and on the base of the first metacarpal bone.

It extends the thumb, and brings it a little towards the other fingers.

§ 1144. Sometimes it is completely double.

XII. EXTENSOR INDICIS PROPRIUS.

§ 1145. The extensor proprius indicis muscle, Cubilo-sus-phalangettien de l'index , Ch. (JVf. indicator , s. indie atorius, s. indicis extensor , s. abductor ), is nearly as large as the preceding. It arises directly below it by two slips from the third quarter of the anterior face of the ulna, and near the lower part of the fore-arm becomes a strong tendon, which, covered by that of the extensor digitorum communis, passes with it through the third division of the dorsal ligament of the carpus, below the tendinous band which goes from the latter muscle to the indicator finger ; it proceeds more inwardly than this band, and is attached to the base of the first phalanx of the finger, blending with it.

It extends the indicator finger, and approximates it a little towards the third.

§ 1146. Sometimes it is digastric, and interrupted in its course by a long tendon.(l)

This muscle presents several anomalies which are exceedingly interesting : they consist in its more or less perfect multiplication and in the formation of the extensor pollicis tertii proprius.

The lowest degree of this anomaly is the division of its portion into two slips both of which go to the second finger, (2) or the division of its belly into two parts, the tendons of which unite before arriving at this finger, (3) or finally the existence of two bellies of the usual size, which are entirely distinct., and of which one arises from the radius. (4)

The most complete anomaly is when one of the slips of the tendon does not go to the indicator, but to the middle finger. (5)

Sometimes a small and perfectly distinct muscle arises from the lower part of the outer face of the radius and from the dorsal ligament of the carpus, and is attached to the first phalanx of the indicator. (6) This variety is only a more perfect development of the case in which the muscle arises by two heads.

Next comes the anomaly where we find a proper extensor of the middle finger ; this muscle is always smaller than the extensor indicis

(1) Rosenmüller, loc. cit., p. 6.

(2) We have seen it several times.

(3) Albinus, p. 45S. — Heymann, p. 13.

(4) Gantzer, p. 14.

(5) Albinus, p. 468. — Peitsch, Syllogc obs. anat.

(6) Albinus, Ann, acad.. vol. iv. ch. vi.— Hevmann, p. 12.

Vol. II. 17


130


DESCRIPTIVE ANATOMY.


proprius, and arises more or less below and under it. This formation varies the least possible from the normal state when the new muscle comes from the ulna;(l) but sometimes it arises from the radius(2) or from the dorsal ligament of the carpus. (3)

The greatest anomaly is where we find, beside the extensor indicia proprius, an extensor for the middle finger, which divides into two tendons, one of which is attached to the metacarpal bone of the index finger, and the other to that of the middle finger.

Finally, we have seen in one case a small tendon, which extended from this proper extensor of the middle finger to the base of the first phalanx of the index finger.

All these anomalies are curious in two respects : 1st, as a repetition of the normal formation of the lower extremities, since they represent the extensor communis digitorum brevis, and that more perfectly as the supernumerary muscles arise lower ; 2d, as analogous with animals ; for in many apes the tendon of the extensor indicis proprius furnishes a slip to the middle finger, and in others, for instance in the simia apella, we find a proper extensor of the index finger. (4)

II. MUSCLES OF THE INTERNAL FACE OF THE FORE-ARM.

I. palmaris Longus and brevis and the palmar aponeurosis.

§ 1147. The palmaris longus muscle, Epitrocldo-palmaire , Ch., is a thin oblong muscle, which arises, directly below the preceding and farther back than it, from the upper part of the anterior face of the inner condyle of the humerus. It goes directly forward and downward, and becomes in the middle of the fore-arm a broad and thin tendon, which is very near the skin. This tendon however is covered by the anti-brachial aponeurosis in most of its length, and passes over this aponeurosis only at its lower part. At its lower end, it divides into two fasciculi : the anterior, which is shorter, and which is attached to the posterior end of the abductor pollicis ; and the posterior, which is much larger, and is called the palmar aponeurosis ( aponeurosis palmaris). This aponeurosis is thinner than the tendon, but much broader and triangular. It gradually enlarges from behind forward, so that it corresponds by its anterior edge to the four fingers. It however becomes thin, and its fibres occasionally have intervals between them.

It is composed essentially of longitudinal fibres, like the tendon of which it is the expansion. Its anterior edge is however formed of transverse fibres, which are arranged over the preceding.

It covers most of the muscles of the palm of the hand, except those of the thumb and the little finger.

(1) We have seen it several times.

(2) We have seen it once.

(3) Brugrione, loc. cit., p. 168.

(4) Meckel, Bey trage zur vergleiehéndeji anatomie, vol. ii. p. 11.


MYOLOGY.


131


The palmaria brevis muscle, which is composed of transverse fibres, is attached to its internal edge at its upper part. This muscle, the internal edge of which comes from the skin, serves to tense the aponeurosis outwardly.

§ 1148. The palmaris longus muscle is often deficient ; sometimes it is replaced by a tendon of the flexor digitorum sublimis.(l ) In other cases, on the contrary, it is unusually developed in fact thinner, but very broad, and descends almost into the palm of the hand. (2) This rudiment of a peculiar muscle, which sometimes extends from the coronoid process of the ulna to the palmar ligament of the carpus, is worthy of remark, especially as it forms an analogy with apes. (3)


II. RADIALIS INTERNUS.

§ 1149. The radialis internus muscle, Epitrochlo-metacarpien , Ch. (JVT. radial is internus, s. flexor manus radialis), is much larger than the preceding, and is blended above with it, and on both sides with the pronator-teres and the flexor communis digitorum sublimis ; it comes from the anterior face of the inner condyle of the humerus, and sometimes also by a small head from the radius. It is partly covered by the preceding and goes downward and a little forward, and near the middle of the fore-arm becomes a broad tendon. This tendon passes under the palmar ligament of the carpus in a special canal, formed by the palmar ligament, and by the os trapezium ; it is harder and thicker in this place than in other parts. After leaving this canal it becomes thinner but broader, and is attached partly to the os trapezium, but more particularly to the inner face of the second metacarpal bone.

We find a mucous bursa between the lower end of the tendon, the os trapezium, and the proper palmar ligament.

This muscle flexes the hand and carries it a little forward.

III. PRONATOR TERES.

§ 1150. The pronator teres muscle, Epitrochlo-radial, Ch., a shorter but stronger muscle, arises by very short tendinous fibres from the upper edge and the upper part of the anterior face of the inner condyle of the humerus. It swells a little below its origin, goes obliquely downward and forward, and is covered at its lower part and at its upper edge by a strong tendinous expansion, and is attached by means of this, below the supinator brevis, and before the abductor pollrcis longus, to the anterior face and outer edge of the radius, a little above its centre.

It turns the radius and also the hand inward, forward, and downward.

(1) Rosenmüller p. 6.

(2) Albinas, p. 474.

(3) Perrault, Mem. in Valentin i Theatr. zoot. p. 151. — Virq. ü’Azyr., Eveycl, meth., sect.anat., vol. ii. p. 25, 257.


132


DESCRIPTIVE ANATOMY.


§ 1151. It is sometimes double. In this case the supernumerary muscle extends from the posterior edge of the ulna to the posterior edge of the normal muscle, which is an analogy with apes.

IV. FLEXOR ULNARIS.

§ 1152. The flexor ulnaris muscle, Cubito-carpien , Ch. (JVT. ulnaris internus, s. flexor ulnaris), arises by two rather short heads, of which the upper comes from the lower part of the inner face of the inner condyle of the humerus, and the posterior or the inferior from the inner face of the olecranon process of the ulna. It descends along the ulna, from which it is always separated by the flexor digitorum communis, and becomes a strong tendon at the lower end of the fore-arm which is attached to the pisiform bone ; we find a very loose mucous bursa between it and this bone.

It flexes the hand and inclines it toward the ulna.

V. FLEXOR DIGITORUM COMMUNIS SUBLIMIS.

§ 1153. The flexor digitorum communis sublimis muscle, Epilrochlophalanginien commun , Ch. (JM. flexor digitorum communis sublimis , s. perforatus ), arises below the four preceding, by a much larger head, from the lower part of the anterior face of the inner condyle of the humerus, from the inner part of the capsular ligament of the elbow joint, and from the inner face of the coronoid process of the ulna ; it also arises by a small slip from the inner face of the radius at the lower end of the supinator brevis muscle. Tong before this slip has joined the upper head, it divides into three bellies, of which the internal and posterior divide still lower into two others. Each of these bellies becomes a tendon, which all pass under the special palmar ligament of the carpus to arrive at the palm of the hand.

Nearly opposite the centre of the first phalanx each tendon divides into two slips which unite farther on the second phalanx, so that their inner fibres interlace and again separate below this point to attach themselves behind the middle of the second phalanx to its radial and ulnar edges.

These tendons are surrounded by a common sheath, near the lower extremity of the fore-arm, which, when arrived at the carpus, divides into several sacs, each of which goes with one of them to the base of the first phalanx. This muscle flexes the second phalanx of the fingers.

§ 1154. One of the tendons, particularly that of the little finger, is sometimes deficient ; it is then replaced by one of the tendons of the flexor profundus muscle ; sometimes a belly of this muscle, especially that which belongs to the index finger, is entirely separated from the others, and divided besides into two fleshy portions by a long central tendon. As the anomaly is seen more commonly in the belly of the indicator finger, it is worthy of remark, from its analogy with the outer


descriptive anatomy.


133


face of the fore-arm, since it represents the proper extensor of the index finger, and more, as the latter is also digastric in some subjects.


VI. FLEXOR DIGITORUM PROFUNDUS.’

§ 1155. The flexor digitorum profundus muscle, Cubit n-phalangettien commun, Ch. (JVJ. flexor digitorum communis profundus, s. suadus perforons), is stronger than the preceding, which covers it anteriorly, and arises from the upper two-thirds of the inner and posterior faces of the ulna, so as to envelop this bone almost entirely, and divides, but much deeper than the flexor sublimis, into four bellies, which become as many tendons. These tendons are retained together by numerous intermediate filaments and by folds of the mucous sheaths, and pass under the palmar ligament of the carpus, with those of the preceding, and go to the same fingers. In this place we see a fissure along the upper and lower faces. They pass through the sheath of the flexor sublimis, afterwards become broader and thinner, and are attached to the base of the third phalanx.

This muscle flexes the third phalanx of the fingers.

§ 1156. Sometimes a muscle proceeds between the flexor sublimis and the flexor profundus, and extends from the inner condyle of the humerus to the latter ;(1) and again, a muscular fasciculus arises from the flexor pollicis longus as high as the wrist, which is attached by a tendinous expansion to that tendon of the flexor profundus which goes to the index finger.(2)


VII. LIGAMENTS OF THE FLEXORS OF THE FINGERS.

§ 1157. The tendons of the flexor profundus and sublimis are surrounded in two places by fibrous ligaments and mucous sheaths. 1

§ 1158. The upper fibrous ligaments are the common palmar ligament and proper palmar ligament of the carpus.

Below them we find the upper mucous sheath, an elongated sac, which surrounds all the tendons of the two flexors, commences about an inch and a half above the radio-carpal articulation, and extends to the centre of the carpus. Its outer layer is attached to the palmar ligaments of the bones of the carpus, and to the interossei muscles. Numerous folds arise from all the internal face of this outer layer which go inward, surround the tendons of the two flexors, and unite them but very loosely.

§ 1159. The second place, where the common flexors are surrounded with similar ligaments, is that portion which corresponds to the lower face of the fingers.

§ 1160. The lower fibrous ligaments are situated outwardly, and form for the mucous sheath an envelop, which is divided on account of the motion of the fingers,

(1) Gantzer, p. 13.

(2) Gantzer, ibid.


134


DBSCJIII’TIVE ANATOMY.


The strongest portion is termed the ligamentous sheaths ( Lig . vaginalia). These sheaths are formed almost entirely of transverse fibres ; in part, however, especially on the surface, of oblique fibres which cross the preceding. They are strongly extended, like a bridge, from the radial to the ulnar edge of the first and second phalanges. That of the indicator finger is much stronger than the others in every respect.

The feeblest which stand more distinct, extend in the same manner over the metacarpo-phalangoean and the second phalangoean articulations. Their size diminishes much from the first to the third articulation. They are called the ligamentous rings of the articulations ( annuli juncturarum ligament osi).

Analogous fasciculi are found between the preceding and the ligamentous sheaths ; these are the oblique or crucial rings of the first and second •phalanges ( annuli obliqui , s. cruciati phalangis primes et secundcE ).

§ 1161. The inner faces of these fibrous ligaments are covered with elongated mucous sheaths, which begin some lines behind the metarcarpo-phalangÅ“an articulation, are attached in this place to the flexor sublimis and profundus of each finger, and extend to the centre of the terminating phalanx. Their upper part is inserted in the upper part of the palmar face of the phalanges. The tendons of the two flexors are mostly loose in these mucous sheaths, of which each finger possesses a separate one ; however, from the dorsal face of the sheaths, that which covers the palmar face of the fingers, arise several broader and narrower irregular folds, the largest of which contains more or less fat ; these proceed from before backward, are very thin from one side to the other, and are attached to the tendons of the flexor sublimis and profundus. The upper are usually very thin and rounded, and are attached to the radial slip of the flexor sublimis. They are generally deficient in one or several fingers.

The succeeding which are larger are also more constant ; they arise near the second phalangcean articulation, and are usually attached to the tendon of the flexor sublimis, where its two slips unite. Usually we find also within or on their sides other prolongations, which go to the tendons of the flexor profundus.

A third prolongation generally arises from the base of the third phalanx which is attached directly to the two anterior slips of the flexor sublimis, unites them, goes from this point to the anterior extremity of the flexor profundus which covers the third articulation, and is there attached in all its extent.

Other single or divided prolongations extend also in many parts between the tendons of the two flexors in their course along the fingers.

These are the short and long accessory or vascular ligaments of the flexors (vincula tendinum sublimis el profundi accessoria , s. vasculosa brevia et longa).


MYOLOGY.


135


VIII. FLEXOB POLLICIS LONGUE.

§ 1162. Th e flexor proprius pollicis longus muscle, Radio-phalangettien du pouce , Ch., is much feebler and shorter than the preceding, with the second belly of which its central part usually adheres more or less intimately. It arises by a small distinct slip from the tubercle of the ulna, but in most of its length it arises by fleshy fibres from the lower two-thirds of the inner face, and the anterior edge of the radius. The strong tendon which terminates it passes under the palmar ligament with those of the two preceding muscles, and goes between the abductor and flexor pollicis brevis on the internal face of this finger, and is attached not far from its inferior edge to the second phalanx. This tendon is surrounded by a special mucous sheath from the lower extremity of the fore-arm to the centre of the first phalanx.

It flexes the second phalanx of the thumb.

We sometimes find a second head which comes from the inner condyle of the humerus, and which is only a greater development of its upper slip.

IXL .PRONATOR Q.UADR ATUS.

§ 1163. The pronator quadratus muscle, Cubito-radial , Ch. (JV I. pronator quadratus, s. inferior), is an almost equilateral quadrilateral muscle, being rather more long than broad, which occupies the lowest part of the inner face of the fore-arm, where it is covered by the tendons of all the long muscles. Its fibres are oblique and extend from the posterior edge and from the inner face of the ulna to the inner face and anterior edge of the radius.

This muscle rotates the radius, and the hand with it, on its axis from behind forward and from without inw T ard.

§ 1164. It is sometimes deficient, (1) as in several mammalia.

Again, it is sometimes divided into two bellies which are entirely separated, the fibres of which proceed in opposite directions and cross. (2)


ARTICLE FIFTH.

MUSCLES OF THE HAND

§ 1 165. The musclesof the hand(3) arisefrom the tendonsof the flexor profundus, from the carpus, and from the metacarpus, and are attached to the metacarpal bones and also to the phalanges. They are principally designed to approximate and separate the fingers and serve less

(1) We know of one instance.

(2) We have once seen this.

(3) Albinus, leones musculorum inanus iv., ad ealeem hist, muscul., Leyden, 1734,


136


descriptive anatomy.


to flex them. Hence they are divided into abductors, adductors, and flexors. The adductors and abductors which are attached to the two external fingers, the thumb, and the little finger, fulfill only the one or the other of these two functions, while those which move the other three fingers are both adductors and abductors ; because, in approxiting a finger toward that on one side, they necessarily separate it from that of the other side.

The abductor and adductor muscles of the fingers, except the thumb, are] called the interossei muscles, from their situation ; the flexors of the second and third and also one of the little finger are called the lumbricales , from their form.


I. LUMBRICALES.

§ 1166. The four lumbricales muscles, Palmi-phalangien, Ch., are long, rounded muscles, which arise fleshy from the lower face and the radial edge of the tendons of the flexor digitorum profundus toward the upper end of the metacarpus. They proceed at the side above and below these tendons and arrive at the fingers, where they become thin tendons, which are reflected on the radial face of the first phalanx, enlarge, and blend with the anterior edge of the tendon of the extensor muscle.

They flex the first phalanx.

§ 1167. We often find one or more of these muscles more or less completely double, and then the supernumerary head or the whole muscle is inserted in the ulnar side of the adjacent finger.

II. INTEROSSEI.

§ 1168. The interossei muscles, Metacarpo-phalangiens latéraux sus-pahnaire and the métacarpo-phalangiens Intermix, Ch., are situated between the metacarpal bones. Their anterior tendons are attached partly to the lateral faces of the posterior heads of the first phalanges, partly also to the extensors of the fingers. They are divided into two classes, the external (JVT. interossei externi , s. bicipites), and the internal (M. interossei interni , s. simplices.)

I. INTEROSSEI EXTEBNI.

§ 1169. The common characters of the external interossei muscles are : 1st. They appear on the dorsal and palniar faces of the hand. 2d. They arise from the corresponding faces of two metacarpal bones by two heads, which is inserted in a common tendon.

We number four, which are attached to the index, middle, and little fingers.

The first, which is the strongest, is situated between the thumb and the index finger. It differs from the others, not only in volume but also in the complete separation of its two heads.


MYOLOGY.


137


The anterior and stronger head arises from the upper larger part of the ulnar face of the metacarpal bone of the thumb. The posterior, which is smaller, arises from almost all the radial face of the second metacarpal bone. These two heads unite below in a common tendon, which is attached partly to the radial face of the base of the first phalanx of the index finger, and partly blends with the tendon sent by the common extensor of the same finger.

The great distance between the two heads has led some anatomists to consider them as two distinct muscles : they have termed the anterior head the adductor indicts and the posterior the first internal interosseous muscle.

It draws the second finger toward the thumb.

The other external interosseous muscles are much smaller ; their heads unite much higher even in the centre of their course.

The second arises by a smaller anterior and deeper head from the ulnar side of the second, and by a larger posterior looser head from the radial side of the third metacarpal bone. It is also attached to the radial side of the middle finger.

This muscle brings the middle finger toward the index finger.

The third, situated in the space between the third and fourth metacarpal bones, is inserted in the ulnar side of the middle finger.

It brings the middle finger toward the fourth.

The fourth is placed between the fourth and fifth metacarpal bones, and is inserted in the ulnar side of the fourth finger.

It brings the ring finger to the fifth,

II. INTEBOSSEI INTERNS.

§ 1170. The interossei intemi muscles are three in number, when we do not consider the posterior head of the first external interosseous muscle as the first internal interosseous muscle. They are attached to the second, fourth, and fifth fingers. They arise by a single head from the lateral face of the metacarpal bone of the finger to which they are attached, and are very distinct in the palm of the hand.

The first arises from the ulnar face of the second metacarpal bone, is inserted in the ulnar side of the base of the first phalanx of the indicator finger, and blends in the same place with the tendon sent by the common extensor to this finger. It separates the index finger from the thumb and draws it toward the middle finger.

The second comes from the radial side of the fourth metacarpal bone.

The third arises from the radial side of the fifth metacarpal bone.

The second is attached to the first phalanx of the fourth finger, and the third to the first phalanx of the fifth finger.

Both draw the fingers to which they are attached from the side of the thumb or from the radial edge of the hand, and consequently inward.

VOL. II.


18


138


DESCRIPTIVE ANATOMY.


The index finger has then an external and an internal interosseous muscle ; the middle finger has two external interosseous muscles ; the fourth finger an external and an internal, and finally the fifth finger an internal interosseous muscle.

§1171. The interosseous muscles rarely present anomalies. We have however found the second external interosseous muscle attached to the ulnar side of the index finger, and the first internal interosseous muscle attached not to this finger but to the radial side of the third — a variety the more interesting in the history of the inversion of the organs because it presents an exact repetition of the normal formation of the foot, and because the hand in which we found it presented also an adductor of the thumb, formed likewise in the same manner as that of the great toe.

III. MUSCLES OF THE THUMB.

§ 1172. The metacarpal bone of the thumb is surrounded by a considerable muscular mass, called the ball of the thumb (thenar), formed of four muscles, the abductor pollicis brevis, the opponens pollicis, the flexor pollicis brevis, and the adductor pollicis.

I. ABDUCTOR POLLICIS BREVIS.

§ 1173. The abductor pollicis brevis muscle, Carpo-sus-phalangien du pouce, Ch., the most superficial of the four muscles, arises from the anterior part of the inner face of the ligament of the carpus and of the os trapezium. It is generally blended by a short intermediate tendon with the tendon of the abductor longus (§1139), and extending forward along the radial edge of the metacarpal bone of the thumb, it is attached by a short tendon to the outer face of the posterior head of its first phalanx. It also usually blends more anteriorly with the tendon of the flexor pollicis brevis muscle.

It separates the thumb from the index finger and extends it a little.

II. OPPONENS POLLICIS.

§ 1174. The opponens pollicis muscle, Carpo-metacarpien du pouce, Ch., is smaller than the preceding, which it partly covers, and its form is rhomboidal. It arises below it by a broad edge and by very broad tendinous fibres from the anterior part of the inner face of the palmar ligament and from the os trapezium, then descends to the metacarpal bone of the thumb, and is attached by a short tendon to all the anterior part of its radial edge.

It draws the thumb inward and turns it on its axis ; so that it opposes its palmar face to that of the other fingers.


MYOLOGY.


139


III. FLEXOR POLLICIS BREVIS.

§ 1175. The flexor pollicis brevis muscle, Carpo-phalangien du pouce, Ch. {J\l. flexor pollicis brevis , s. mesothenar , s. antithenar ), is stronger than the two preceding. Its upper extremity, which is very much divided, arises first below and inward from the palmar ligament and the os trapezium, on the other side from the palmar face of the os trapezoides, from the os magnum, and the os pyramidale. It partly covers the preceding and is attached to the outer sesamoid bone of the thumb.

It flexes the first phalanx of the thumb.

§ 1176. The largest head, which comes from the palmar ligament, is sometimes entirely separated from the other, which is smaller and situated lower ; so that this muscle is in fact double. On the other hand, it often happens that the small head is entirely blended with the adductor pollicis muscle.

IV. ADDUCTOR POLLICIS.

§ 1177. The adductor pollicis muscle, JVIetacarpo-phalangien du pouce , Ch. (JVT. mesothenar , s. hypothenar ), is the strongest and the deepest of the four muscles of this finger. Its form is triangular, the base looking toward the ulnar edge and the summit toward the radial edge. It arises by fleshy and tendinous fibres from the palmar face of the os magnum, and in a greater or less extent from the palmar edge of the third metacarpal bone, goes forward and outward, and is attached by a short tendon to the inner sesamoid bone.

This muscle draws the thumb toward the index finger and slightly rotates it on its axis, so that it turns its palmar face toward that of the other fingers.

§ 1178. Sometimes it divides into a posterior and an anterior belly, which are completely distinct, the posterior being the larger. In this case the first arises only from the os magnum or at the same time from this bone and a small upper portion of the third metacarpal bone : as to the second, it comes from the lower part of the anterior head of the third and fourth metacarpal bones ; sometimes also from the fifth as well as from the capsular ligament of the first phalangean articulation, and goes across or a little obliquely from before backward, to the first phalanx of the thumb, where it unites with the posterior head.

This anomaly is worthy of remark, as it coincides perfectly with the normal arrangement of the adductor of the large toe.

IV. MUSCLES OF THE LITTLE FINGER.

§ 1179. The little finger is moved by three muscles, an abductor, a flexor, and an adductor.


140


DESCRIPTIVE ANATOMY.


J. ABDUCTOR MINIMI DIGITI.

§ 1180. The abductor minimi digiti muscle, Carpophalangien du petit doigt , Ch., the shortest of these three muscles, extends along the ulnar edge of the metacarpus. It arises by short tendinous fibres from tire pisiform bone, and near the first phalanx of the finger becomes a small flat tendon, which blends with the ulnar edge of the tendon of its extensor.

It separates the little finger from the others.

II. FLEXOR MINIMI DIGITI.

§ 1181. The flexor minimi digiti muscle (JVF. flexor proprius digiti quinii ) is covered by the preceding. It arises below and before it from the pisiform bone and from the unciform process of the unciform bone : it forms a short tendon forward, which is attached to the radial side of the first phalanx of the little finger.

It flexes the little finger and separates it from the others.

It is often deficient and then the preceding is more developed.

III. ADDUCTOR MINIMI DIGITI QUINTI,

§ 1182. The adductor minimi digiti muscle, Curpo-metacarpien du petit doigt , Ch. ( J\'L adductor digiti quinii) ) is thickest and shortest, and arises from the lower anterior edge and the outer face of the unciform process of the unciform bone, goes upward, and is attached to all the ulnar face of the metacarpal bone of the fifth finger.

It carries the little finger forward and draws it toward the others, causing it to rotate around its axis on the metacarpal bone. When it acts in concert with the opponens pollicis muscle, which very much resembles it, the cavity of the palm of the hand enlarges.

§ 1183. The proper muscles of the thumb and little finger are only the lumbricales or interossei muscles largely developed and divided into several fasciculi. We must consider the flexor pollicis brevis muscle as the first lumbricalis. The abductor pollicis brevis and the opponens pollicis correspond to an external ; the adductor represents an internal interosseous muscle.

The abductor and the flexor minimi digiti muscles form only one muscle, which represents the last external interosseous muscle.

The adductor minimi digiti muscle is only an enlarged internal interosseous muscle.


MYOLOOT.


141


CHAPTER II.

MUSCLES OF THE LOWER EXTREMITIES.

§ 1184. The muscles which have with the upper section of the abdominal members relations similar to those which exist between the superficial muscles of the back and of the region of the shoulder, or the broad muscles of the abdomen, have already been examined. We may then pass immediately to those which go from the first section of the bones of the lower extremities to the femur ; but we must here also commence by describing the general aponeurotic envelop.


ARTICLE FIRST.

APONEUROTIC 8HEATH OF THE LOWER EXTREMITIES.

§ 1185. Most of the muscles of the lower extremities, especially those of the thigh, leg, and sole of the foot, are enveloped by an aponeurotic expansion, which is not arranged every where in the same manner.

This expansion is called on the thigh the fascia lata , on the leg the crural aponeurosis, in the sole of the foot the plantar aponeurosis.

The first two form a whole more continuous with each other than with the plantar aponeurosis, and are also still more similar in their form, as they surround the thigh and the leg.

The fascia lata commences behind on the gluteæus maximus muscle, where it is very thin, and gradually loses itself at its upper portion. It arises forward from the iliac crest and from the Fallopian ligament. It ■extends as far as the knee. It adheres very intimately by the upper and external part of its anterior edge to the lower edge of the tendon of the obliquus externus abdominis muscle, to which it is much more loosely attached on its inner side.

It is thickest at the outer part and thinnest at the inner part of the thigh. It is half a line thick in every part and above even a line in the first region, while it hardly equals the twelfth of a line in the second. In general it is evidently formed of two layers of fibres : the internal is stronger and its fibres are longitudinal ; the external is weaker and its fibres are oblique downward, inward, and backward, and are more insulated, and gradually approach each other from below upward.

From the inner face of this aponeurosis arise septa which extend between most of the muscles of the thigh which they separate from each other ; we readily distinguish in most of these septa transverse and oblique fibres.


142


DESCRIPTIVE ANATOMY.


The fascia lata presents oblique fibres in every part In many places, especially at the inner portion of its circumference, these fibres are extended over a layer which is not evidently fibrous, especially forward, but at the outer part this layer is manifestly formed of longitudinal fibres, and at the same time its inner face presents in different parts more insulated oblique fibres, so that here the aponeurosis evidently consists of three layers.

The outer part of the crural aponeurosis is also much thicker, and formed in this part of two layers ; the fibres of the internal are longitudinal, those of the external, which is weaker, are oblique.

At the upper part of the aponeurosis the direction of the oblique fibres is inversely that of the oblique fibres of the fascia lata, that is, they proceed forward, downward, and inward.

At the lower part of the crural aponeurosis they have an opposite direction, and at the same time other fibres are developed on the inner side of the aponeurosis, which are oblique from behind forward and from above downward.

These outer and inner fibres cross on the anterior face of the articulation of the foot, and as they increase in strength in this part they there form the crucial ligament ( Lig . cruciaturn ), composed of two fasciculi, which cross each other in the centre. One of these fasciculi descends from the outer malleolus, goes downward and inward, and is attached to the tibial side of the first metatarsal bone. The second arises from the internal malleolus, and goes to the tuberosity of the fifth metatarsal bone.

Below, they are both continuous with the thin aponeurosis of the back of the foot, which covers the tendon of the extensor digitorum longus and the belly of the extensor communis digitorum pedis, and is lost near the anterior extremity of the metatarsus.

This aponeurosis at the back of the foot is often much stronger toward the posterior end of the first metatarsal bone in this place,where it passes over the tendon of the extensor proprius pollicis pedis,, than in the rest of its extent, and it is formed of very evident transverse fibres, which are attached internally to the inner side of the metatarsus, and outside to a special fasciculus of the extensor brevis digitorum pedis. In this case, this portion of the aponeurosis of the foot is provided with a proper tensor muscle.

II. TENSOR VAGINÆ FEMORIS.

§ 1186 . The aponeurosis of the fascia lata, like most of the aponeurotic expansions which surround the muscles, has a proper muscle called the tensor vaginic femoris muscle, llio-aponeurosi-f amoral , Ch. (M. tensor fasciœ latœ).

This muscle is situated at the anterior edge of the upper part of the lateral face of the thigh. It arises by a short but very strong tendon from the outer face of the anterior and superior spine of the ilium.


MYOLOGY.


143


Thence it goes downward and outward, gradually enlarges, and is continuous by very short tendinous fibres, towards the summit of the middle third of the thigh, with the fascia lata, which is united with its outer face more firmly than with any other muscle.


ARTICLE SECOND.

MUSCLES OF THE PELVIS.

§ 1187. The muscles of the pelvis arise partly from its outer face, partly from its inner face, and partly from the lumbar portion of the vertebral column ; they are attached to the upper part of the femur which they extend, flex, and turn around its axis.

I. EXTENSORS OF THE THIGH.

§ 1188. The thigh is extended by three muscles called the glutÅ“i, situated over each other ; and they cover the outer face of the iliac bones, and descend outward, downward, and forward toward the femur.

I. GLUT2EUS MAXIMUS.

§ 1189. The gluiœus maximus muscle, Sacro-femoral, Ch., is the largest of all the muscles of the body, and is nearly a regular rhomboid. It arises by its posterior and inner edge from the posterior part of the outer lip of the crest of the ilium, from the lower part of the posterior face of the sacrum, from the sacro-sciatic ligament, and from the sciatic tuberosity. It arises by these différent points by short tendinous fibres, goes from within outward and from above downward, forming a very strong and thick muscle, composed of distinct and large fasciculi which are loosely connected with each other. It is attached by a broad and very strong tendon which is continuous below with the lateral part of the fascia lata to the lower part of the large trochanter, and to the linea aspera which descend from this tubercle.

Several mucous bursae are found on the inner face of the lower tendon of this muscle. The largest and at the same time the uppermost is situated between it and the outer face of the large trochanter. Farther backward and downward we find another which is also large but a little smaller, between it the upper extremity of the vastus externus muscle and the lower end of the tensor vaginae femoris muscle. Finally, between this muscle and the femur, farther backward and downward, are two which are smaller.

The glutæus maximus extends the thigh, brings it toward the vertebral column, rotates it a little outward, and approximates it to that of the side opposite. When it acts from below upward it draws the iliac bones downward, inward, and forward.


144


DESCRIPTIVE ANATOMY.


II. GLUTÆUS MEDIUS.

§ 1190. The glutÅ“us médius muscle, Grand ilio-trochanierien, Ch., is a large muscle, but smaller and closer than the preceding, and has a triangular form. It is covered at its posterior and lower part by the glutæus maximus, and forward by the fascia lata only, with which it is intimately connected. It arises from the outer lip of the crest of the ilium, and from the upper and anterior part of the outer face of the iliac bones which is situated between the iliac crest and the curved line. Its posterior fibres are oblique from behind forward and from without inward ; the anterior go from above downward. It proceeds towards the large trochanter, and is attached to its outer face by a broad, short, and very strong tendon, which blends with that of the glutæus maximus muscle.

A small mucous bursa exists between the upper face of this muscle, the pyrifarmis, the gemellus superior, and the inner face of the large trochanter.

The glutæus médius muscle raises the femur, separates it from that of the opposite side, and inclines the pelvis as much as possible towards its side.

Its posterior part turns the thigh outward, and its anterior turns it inward.


III. GLUTÆUS MINIMUS.

§ 1191. The glutœus miniums muscle, Petit ilio-trochanterien, Ch., has the same form as the preceding, while it is much smaller and is entirely covered by it. It arises directly below it by its upper face and anterior edge from the curved line, and from the anterior and lower part of the outer face of the iliac bones. It is attached by a short and strong tendon to the upper edge of the upper part of the inner face of the large trochanter.

A small synovial capsule exists forward between it and the large trochanter.

Its action is the same as that of the preceding.

II. MUSCLES WHICH ROTATE THE THIGH OUTWARDLY.

§ 1192. The thigh is turned outward by six muscles, the pyriformis, the obturator internus, the obturator externus, the two gemelli, and the quadrat us femoris.

I. PYRIFORMIS.

§ 1193. The pyriformis muscle, Sucro-lrochanterien , Ch. (JVT. pyriformis, pyrimidalis, iliacus externus), is a small muscle of an oblong


MYOLOGY.


145


triangular form coming from the cavity of the abdomen, where it arises by three or four digitations from the sacrum. It arises from the anterior face of this bone, between the third and fourth, the second and third, and the first and second pairs of the anterior foramina of the sacrum, , and from the inner face of the posterior and lower spine of the ilium, and from the upper part of the posterior edge of the iliac fossa. It descends through this last behind the upper part of the descending branch of the ischium, goes outward and forward, and is attached by a rounded, strong, and proportionally broad tendon to the summit and upper part of the inner face of the large trochanter.

There is a small mucous bursa between its tendon and the gemellus superior muscle.

It rotates the thigh outward, separates it from that of the side opposite, and raises it a little.

§ 1194. It sometimes divides into an upper and a lower portion, between which the glutæal nerve passes. (1)

II. OBTURATOR INTERNUS.

§ 1195. The obturator internus muscle, Sous-pubio-trochanterien interne , Ch. (AT. obturator internus , s. marsupialis, marsupialis internus ), arises from the inner face of the obturator foramen by radiating fibres, which suddenly change their direction on leaving the pelvis and turn at a right angle on the posterior face of the descending branch of the ischium, covered before by this part of the bone, and behind by the sacro-sciatic ligament. It then proceeds outward and forward, and is attached by a strong tendon to the central part of the inner face of the great trochanter, far below the tendon of the pyriformis muscle.

The arrangement of this tendon is then very peculiar. It begins within the pelvis, a short distance from the descending branch .of the ischium, but extends to about the centre of the space between the ischium and the trochanter. It does not appear except on the anterior and inner face of the muscle, where it consists of five very regular and very distinct fasciculi, two of which form the upper and lower edge of the muscle. The outer extremity of the middle belly extends between them by four triangular fasciculi, and then immediately unite in a strong tendon near the centre of the space between the ischium and the great trochanter.

We find an oblong synovial capsule backward and outward between the tendon of this muscle, the gemelli, and the great trochanter. A second, external and rounded, situated between the ischiatic spine and the great trochanter, surrounds the inner part of the tendon.

The obturator internus muscle turns the thigh directly outward and draws it from that of the opposite side.

(1) Winslow, Expos, anat., vol. ii. p. 125.


VOL. II.


19


146


DESCRIPTIVE ANATOMY.


III. GEMELLI.

§ 1196. The gemelli muscles, Ischio-lrochanterien , Ch. {M. gemini femoris, marsupiales extend , marsupium ), are two small oblong muscles, which are very similar and placed one over the other : they are separated backward and outward by the tendon of the obturator internus muscle, also by that portion of this muscle which is situated out of the pelvis. Their thin edges touch forward.

The upper arises by a pointed extremity from the lower part of the posterior face of the ischiatic spine.

The lower arises by a broad and semilunar edge from the upper face of the sciatic tuberosity and from the outer face of the descending branch of the ischium. It gradually becomes thicker from within outward.

These two muscles are intimately connected with the obturator internus, especially in their outer portions, entirely cover it, and are attached with it to the inner face of the great trochanter.

They act in the same manner as the preceding.

§ 1197. The upper gemellus is frequently deficient(l) — a remarkable analogy with what is seen in the ape. (2)

We know of one case where both these muscles were deficient, as in bats.

IV. QUADUATUS FEMORIS.

§ 1198. The qnadratus femoris muscle, Jschio-sous- trochanterien, Ch., is oblong and composed of transverse fibres. It is broader from without inward than in any other direction, and its height much exceeds its thickness. It arises from the anterior edge of the sciatic tuberosity and from a small part of the ascending branch of the ischium, passes directly below the gemellus inferior to the posterior face of the femur, where it is attached to a square impression situated between the roots of the large and small trochanters above the posterior intertrochanterian line.

We find a synovial capsule between it and the small trochanter.

It acts like the preceding.

§1199. Sometimes it does not exist. (3) More rarely it is divided into several fasciculi, three of which have been known to exist. (4)

V. OBTURATOR EXTERNUS.

§ 1200. The obturator externus muscle, Sous-pubio-trochantericn externe, Ch., is a rounded and triangular muscle, at first thin, but aftcr (1) trantzor, p. 4.

(2) Vicq. d’Azyr, Knc. méth.syst. anat. des quadrup., p. 29.

(3) Albinus, loc. c it., p. 530. — We know of one case where the gemelli were very large.

(4) Jancke, De caps. tend, arlicul., Leipsic, 1753.


MYOLOGY.


147


wards it becomes thicker and again grows thinner. It arises by a rounded edge from the outer face of the ascending branch of the ischium and by short tendinous fibres from the two branches of the pubis and from the anterior face of the obturator membrane.

After contracting considerably in its outer portion and being covered by a broad tendon on its anterior and posterior faces, it is reflected from the anterior to the posterior face of the body, goes obliquely upward and outward directly behind the neck of the femur, and is attached by a short but very strong tendon to the fossa and to the inner face of the great trochanter, a little distance below the tendons of the obturator internus and the gemelli muscles.

It turns the thigh outward, draws it backward toward that of the opposite side, and brings the anterior face of the pelvis to its side.

III. FLEXORS OF THE THIGH.

§ 1201. There are two flexors of the thigh, the psoas magnus and the iliacus internus muscles : to these a third is usually attached, the psoas parvus muscle ; but this does not always descend to the thigh.

I. PSOAS MAGNUS.

§ 1202. The psoas magnus muscle, Prelombo-trochanterien , Ch. (J\I. psoas magnus, s. lumbaris, s. lumbaris internus ), is a considerable elongated and rounded muscle, occupying the inner and anterior part of the lumbar region directly on the side of the bodies of the lumbar vertebra. It extends from the upper extremity of this region downward and outward to the inner face of the femur.

It arises by an external and posterior and an internal and anterior range of short, flat, and triangular slips from the five lumbar vertebra and the last dorsal.

The anterior slips come from the lateral faces of the short ligaments and the intervertebral ligaments ; the posterior arise from the lower and anterior parts of the transverse processes of the lumbar vertebra.

The belly of this muscle descends outward, covers the inner part of the iliacus internus, becomes rounded as it descends, and forms before the sacro-iliac articulation, rather outward than inward, a strong tendon which emerges from the abdomen below the crural arch behind the femoral vessels, and is attached to the anterior face of the small trochanter.

The psoas magnus muscle bends the thigh and turns it a little inward, bends the trunk and turns it a little toward its side.

§ 1203. Between this muscle and the iliacus internus we sometimes find another smaller, which arises from one or more transverse processes of the upper lumbar vertebra, proceeds on the outside of the psoas magnus muscle, and is attached to the small trochanter and


148


descriptive anatomy.


sometimes to the tendon of the last. The crural nerve usually passes between it and the psoas magnus muscle.(l) This anomaly reminds us of the multiplication of the psoas magnus muscle in several apes. (2)

This and not the next muscle, as some anatomists assert, is the muscle which sometimes exists abnormally.(3)

II. PSOAS PARVUS.

§ 1204. The psoas parvus muscle, Prelombo-pubien, Ch., has an oblong square form, and arises from the lateral face of the first lumbar vertebra, and from the intervertebral ligament between it and the last dorsal vertebra, and sometimes from the twelfth dorsal vertebra. It arises generally by one but sometimes by two slips, which come either from the two vertebrae or only from the first lumbar.

Tt soon after becomes a flat and very long tendon, situated on the outside of the psoas magnus muscle, crosses it to go inward, and is attached in that part where the body of the pubis and ilium unite.

Below, the tendon becomes an aponeurosis, which covers the lower part of the psoas magnus and of the iliacus, is attached to the crural arch, and blends with the fascia lata.

This muscle bends the vertebral column forward and increases the force of the two muscles situated above it, furnishing them with a point of support.

§ 1205. It is sometimes deficient, but this is rare.

III. ILIACUS INTERNUS.

§ 1206. The iliacus internus muscle, Iliaco-troehanterien, Ch. (JVF. iliacus, s. iliacus internus ), is a broad and considerable muscle, which fills all the upper part of the inner face of the iliac bones, whence it descends to the inner part of the thigh. It arises by a semicircular and convex edge and by short tendinous fibres from the inner lip of the iliac bone, and also by fleshy fibres from the inner face of this bone to near the anterior and inferior iliac spine, goes inward and forward, becomes in its course considerably narrower and thicker, and is attached a little above the crural arch to the outside of the tendon of the psoas magnus muscle, by which it is fixed to the anterior face of the small trochanter.

We find a considerable mucous bursa between the common tendon of the psoas magnus and the iliacus internus muscle and the capsular ligament of the coxo-femoral articulation. There is another, which is smaller, between it and the small trochanter.

This muscle bends the thigh and carries it inward. It draws the pelvis and with it the trunk downward and forward.

(1) We have seen it several times. — Albinus, p. 315.

(2) Valentine, Amph. zoot., p. 151.

(3) Kelch, Bcytrœge zur path, anat., p. 22.


MYOLOGY.


149


ARTICLE THIRD.

MUSCLES OF THE THIGH.

§ 1207. Among the muscles which form the mass of the thigh some serve to move it and others act on the leg. Not only the first but also some of the second arise from the bones of the pelvis.

The muscles of the first class are the adductors of the thigh ; those of the second are the adductors, the flexors, and the extensors of the leg.

I. ADDUCTORS OF THE THIGH.

§ 1208. The two lower limbs are drawn toward each other by the adductors ( adductor es ), which form almost all the internal and posterior part of the muscular mass of the thigh. Three of these muscles in particular have been termed the adductors. They have been considered as forming only a single muscle, called the triceps muscle (JVf. femoris triceps ), but wrongly, as they are not united by a common tendon. The fourth has been described as a separate muscle, called the pectinœus , although it might be considered as a fourth head of the common adductor, as well as the other three.

I, PECTINÆUS.

§ 1209. The pectinozus muscle, Sous-pubio-femoral, Ch. ( JW.pecti nœus, s. pectinalis), a flat, long, quadrangular muscle, arises by its upper thin and horizontal edge from the crest of the horizontal branch of the pubis, on which its upper and anterior face passes. It goes from above downward, from within outward, and is attached by a perpendicular edge to the upper end of the inner lip of the rough line of the femur.

We find a small synovial capsule below the small trochanter, betwmen this muscle and the femur.

It draws the thigh toward that of the opposite side, raises it and carries it forward, turns it a little inward, and slightly inclines the pelvis outward and downward.

§ 1210. We sometimes find a second pectinæus, which is smaller, which blends below with the tendon of the other, and is attached above to the inner part of the upper edge of the obturator foramen.(l)

§ 1211. The three adductors, properly so called, are distinguished into the long, the short, and the great adductor.

II. ADDUCTOR LONGUS.

§ 1212. The adductor longus muscle, Pubio-femoral , Ch. (M. adductor femoris longus , caput primum tricipitis ), has the form of an ob (1) Winslow, Expos, anat., vol. i. p. 117.


150


DESCRITTIVB ANATOMY.


long triangle. It is the second of the three adductors in size and the longest of all. It arises by a short, narrow, but very strong tendon from the inner part of the anterior face of the horizontal branch of the pubis, from the spine of the pubis, and from the anterior part of the symphysis pubis. Thence it goes outward and downward, in a direction more oblique than the preceding, becomes broader and at the same time thinner, and is attached by a tendinous and interrupted edge to the third quarter of the posterior lip of the rough line of the femur. Its lower end usually unites to the vastus internus muscle.

Its action is nearly the same as that of the pectinæus.

§ 1213. It is sometimes divided into two. And again, it descends much lower, by a thin tendon united to that of the adductor magnus : so too in some mammalia and in birds the pectinæus or the other portions of the adductor muscle descend very low.

III. ADDUCTOR BREVIS.

§ 1214. The adductor brevis muscle, Sous-pubio-fcmoral, Ch., (JW. adductor femoris brevis, s. adductor secundus, s. caput alterum tricipitis), is rather a broad triangular muscle. It arises at the side of the tendon of the gracilis muscle, but much higher and more externally than it, and is closely united with its upper extremity. Its upper end, situated directly below the adductor longus and formed of very short tendinous fibres, arises from the inner part of the outer face of the horizontal branch of the pubis. It is much broader and much shorter than the preceding, goes less obliquely outward than it, and is attached to the posterior face of the small trochanter and also to the upper third of the inner lip of the rough line of the femur, by several strong tendinous slips, which succeed each other from above downward.

At its lower extremity it is connected more or less intimately with the pectinæus and the adductor magnus muscles.

It acts like the preceding.

§ 1215. It is often partially or wholly divided into two slips, which forms a remarkable analogy between man and the ape.

IV. ADDUCTOR MAGNUS.

§ 1216. The adductor magnus muscle, Ischio-femoral , Ch. (M. adductor femoris magnus, s. caput tricipitis tertium), is the largest of the three proper adductor muscles ; it also has a triangular form, the base of which rests in the thigh, and the apex looks toward the pelvis. It arises from the anterior face of the descending branch of the pubis, and is intimately connected in this part with the outer face of the lower part of the tendon of the gracilis muscle. It arises also from the ascending branch of the ischium and from the lower edge of the sciatic tuberosity.

Its upper and anterior fasciculi go directly downward and outward. The posterior and inferior on the contrary, which are attached to the


MYOLOGY.


151


sciatic tuberosity, go from below upward, around and behind the latter, so that the muscle seems at its upper part to have been twisted on itself, and is much thicker there than in the rest of its coarse.

Before the extremity of the portion inserted in the sciatic tuberosity, the upper edge, which is loose and fissured in a semilunar form, goes toward the femur, where it is attached to the posterior lip of the linea aspera, behind the pectinæus and the other two adductors, always descending deeper than they. The lower tendon is very strong, particularly at its lower part, and extends to the posterior face of the inner condyle of the femur.

About the latter fourth of the thigh this tendon is perforated by the superficial vessels of the leg, which pass from its anterior to its posterior face. It unites below to the vastus internus muscle.

T his muscle draws the thigh inward, carries it forward, turns its anterior face a little outward, flexes the pelvis forward, and directs its anterior face to the side.

§ 1217. We sometimes find it divided into two portions, as in apes.

II. MUSCLES OF THE THIGH WHICH MOVE THE LEG.

§ 1218. The muscles situated on the thigh forming its mass, and which move the leg, are distinguished into adductors, extensors, and flexors.

I. ADDUCTORS OF THE LEG.

§ 1219. Those nearest the surface are the adductors, of these there are two, the sartorius and the gracilis.

A. SARTORIUS.

§ 1220. The sartorius muscle, Uio-pretibial, Cli., the longest of all the muscles of the body, is very thin, and has an elongated square form. The short tendon by which it arises descends lower on its external than on its internal edge. It is inserted directly at the side of the tensor vaginæ femoris muscle, more inward and forward, on the anterior and upper spine of the iliac bone. Thence it passes onward and inward, above the lower part of the adductor iongus and adductor magnus muscles. In this manner it attains the anterior face of the thigh, where its lower portion goes to the inner face of the same part. Thence it proceeds directly forward and at the side of the gracilis, and soon becomes rounder and narrower, and forms a short rounded tendon which, passing behind and below the inner condyle of the femur, comes to the inner face of the leg. In this place it rests directly on the upper part of the inner face of the tibia, it becomes broader, and is at .'ached by its anterior edge to the inner face of this bone, near its sp ! ' -, and is contiguous below with the aponeurotic expansion of the leg.


152


DESCRIPTIVE ANATOMY.


This muscle flexes the knee, and when this articulation is bent it turns the tibia inward, so that the end of the foot approaches the other. When it acts in an opposite direction it draws the haunch a little forward and turns it inward.

§ 1221. We have met with one subject in which the sartorius muscle did not exist.

Sometimes, on the contrary, there are two which may happen in several different ways.(l) The normal muscle usually appears curved inward, and the additional muscle terminates sooner below, where it is attached either to the tendon of the first or to the femur.

Sometimes the fibres of the sartorius muscle are interrupted by a considerable intermediate tendon which is firmly united to the fascia lata. (2)

B. GRACILIS.

§ 1222. The gracilis muscle, Sous-pubio-pretibial , Ch. (JM. gracilis, s. rectus internus), is a thin muscle of an oblong triangular form which arises by abroad base which forms its upper edge, from the anterior face of the lower portion of the descending branch of the pubis, and from the upper part of the ascending branch of the ischium. Thence one of its edges turns forward and the other backward, one of its faces outward and the other inward ; it goes to the inside of the thigh, and above its latter sixth, becomes a thin and rounded tendon, which proceeds directly behind the lower part and the tendon of the sartorius, and turns with it on the inner condyle of the femur. • It is at first covered by it, and is then situated below it, and blended with it in its anterior and inferior part, and is finally inserted a little lower down, in the upper part of the inner face of the tibia.

It bends the knee, turns the leg inward, and draws the anterior face of the iliac bones from the side to which it is attached.

II. EXTENSORS OF THE LEG.

§ 1223. The leg has four extensors which may very properly be considered as one muscle with four heads, since they are attached to a common tendon. They are situated directly below the fascia lata aponeurosis on the anterior face, and on the sides of the thigh, and form most of its muscular mass. A considerable mucous bursa exists between them and the aponeurosis of the thigh. They are termed the rectus femoris, the vastus internus, the vastus externus, and the cruræus muscles.

A. RECHTS FEMORIS.

§ 1224. The rectus femoris muscle, Jlio-rotulien, Ch. {M. rectus femoris, s. extensor cruris médius superficialis), is a strong elongated

(1) Huber, Act. n. c., vol. x. p. 114.— Rosenmüller, loc. cit., p. 7.— Gantzer, p. 14. '

(1) Kelch, loc. cit., p. 42, p. xxxv.


MYOLOGY.


153


pointed muscle situated on the anterior face of the thigh, directly under the fascia lata aponeurosis in most of its length, except its upper part, where it is covered by the sartorius muscle.

It arises by two points from the iliac bone by a very strong but short tendon. In fact, this tendon is divided above into two heads, an upper and a lower or external tendon.

The upper head, which goes directly downward, comes from the anterior and inferior spine of the ilium. The lower, which is curved in a semicircle, arises from the upper part of the edge of the cotyloid cavity. These two heads soon unite to give rise to the upper common tendon. This tendon soon disappears on the posterior part of the muscle, but becomes much broader on the anterior, and descends to its centre, gradually becoming thinner.

The central fleshy portion is composed of an outer and an inner layer of fibres, which unite at an acute angle on the median line, so that the arrangement of these fleshy fasciculi resembles in some measure a roof.

The fibres are much longer, and ascend much straighter the nearer they are to its lower extremity. They are attached on both sides to a prolongation of the upper tendon, the direction of which is from before backward, which descends into the substance of the muscle from its anterior face, and gradually diminishes from above downward. It however continues perceptible to near the lower end of the fleshy belly, that is, much lower than the broad and anterior part of the upper tendon descends on its outer face. It is nowhere connected with the posterior and inferior tendon.

The lower tendon is much longer but is weaker than the upper. It ascends on the posterior face of the muscle, much higher than the upper, descends on the anterior, so that the fleshy belly is situated for several inches before and behind between two tendinous expansions. It begins to be visible forward only towards the lower third of the thigh, and is seen first on the two sides of the fleshy belly, which gradually contracts. It is entirely loose after quitting the last fifth of the thigh. When approaching the patella below, it becomes broader, and is attached to the upper edge of this bone, and is intimately united with the tendons of the other extensors.

This muscle extends the leg when the thigh is fixed, and the thigh when the leg is fixed ; in the latter case it also bends the pelvis a little and turns its anterior face obliquely to the opposite side.

B. VASTUS EXTERNUS.

§ 1225. The vastus externus muscle, ( JVL . extensor cruris vastus, s. externus), ( 1) the largest of all the extensors of the leg, although much shorter than the preceding, forms almost solely the muscular mass on the outside of the thigh ; at the same time it extends very much


(1) This and the next two muscles are termed the Trifemoro-rotulien by Chaussier.

Vol. II. 20


154


DESCRIPTIVE ANATOMY.


backward and forward. It is considerably thick, but it is broader from before backward than from within outward.

It arises by a slightly concave edge which inclines from before backward, from within outward, and from above downward, from the lower part of the anterior and outer face of the great trochanter. The upper half of its posterior edge, situated along the rough line of the the femur, comes from the inner face of the outer wall of the fascia lata aponeurosis. From all these points it gradually descends forward, becomes narrower, and is finally attached, by an inferior tendon, to the upper and outer edge of the patella. The inner part of this tendon is covered some distance above its insertion by the tendon of the rectus femoris muscle, to which it is even slightly united, although it is easily separated from it as far as where it is inserted in the patella.

The muscular fasciculi go directly downward. The upper tendon extends below the centre of the muscle on its outer face, and the lower only to the centre of its inner face.

The vastus externus muscle extends the knee,- and most generally raises the leg at the same time, and turns it a little outward.

C. VASTUS INTERNUS.

§ 1226. The vaslus interims muscle (JVf. extensor cruris , s. vastus interims ) is a little shorter and much weaker than the preceding, with which it is blended outwardly in a small portion of its upper extremity. It arises by its upper edge, which descends obliquely inward, from the anterior intertrochanterian line ; by a small part of its lower edge, from a part of the anterior face of the femur situated below this fine ; and by the upper part of its posterior edge, from the upper part of the anterior lip of the linea aspera. Its lower tendon is attached to the inner part of the upper edge, and to the inner edge of the patella. The inner part of this tendon is covered below by that of the vastus externus which passes obliquely over it, and is attached to the patella before it ; it adheres to this tendon, but is easily separated from it.

The upper tendon of this muscle descends over almost the whole of the inner and loose face on the posterior half of the muscle, while the lower disappears already below the centre of its outer face, principally at its upper part.

This muscle extends the leg and turns it a little inward.

D. CRURÆUS.

§ 1227. The crurczus muscle, (JVT. cruralis, s. crurœvs , s. femorceus) the shortest of the four extensors of the leg, is also nearly as strong as the preceding. It arises by its posterior and inner face, directly below this last, from the larger part of the anterior and the outer face of the femur, excepting a small portion above, and from its lower third. The posterior edge comes from the outer lip of the linea aspera. This


MYOLOGY.


155


muscle covers also most of the anterior and outer faces of the femur. It is attached by its lower tendon behind the vastus internus and the vastus externus to the upper edge of the patella, and usually also at its lower and outer part, by short fibres, to the synovial capsule, and to the outer edge of the patella.

This lower and outer part is generally separated from the others, particularly from their tendon.

The upper edge of this muscle is attached to the bones without any appearance of a tendon. The lower tendon, the loose portion of which is longer than that of the two preceding, begins on the contrary from the middle of the anterior and loose face.

The cruræus muscle is mostly covered above by the vastus externus and the vastus internus ; it is entirely covered below by the rectus muscle, excepting however its outer and lower lateral face, where it is concealed by the vastus internus muscle. Its lower part also is intimately connected with the two vasti, especially the externus.

A capsular ligament exists between its tendon, that of the vastus externus, the capsular ligament and the patella ; this frequently opens into the femoro-tibial articulation.

It extends the knee.

§ 1228. The common tendon of these four muscles, after enveloping the patella, goes to attach itself to the tuberosities of the tibia, where we find a considerable synovial capsule between it and the bone.

E. 6UBCRÃœEALIS.

§ 1229. The subcruralis muscle is a small triangular muscle, which always exists and is entirely covered by the lower part of the preceding. It arises from the lower fourth of the anterior face of the femur, and is attached to the upper part of the anterior wall of the synovial capsule of the knee. It draws this capsule in the motion of extending the leg, and also prevents it from being injured.

III. FLEXORS OF THE LEG.

§ 1230. The flexors of the leg are situated on the posterior face of the thigh. We number three, two internal and an external ; but the latter arises by two heads. All arise at the side of each other from the sciatic tuberosity, and are attached posteriorly to the bones of the leg. They consequently bend the knee or draw the posterior faces of the thigh and of the leg towards each other. They also extend the coxo-femoral articulation when the leg is extended.

I. INTERNAL FLEXORS.

§ 1231. The two inner or tibial flexors arise from the sciatic tuberosity and are inserted in the upper end of the tibia. They are called the semimembranosus and the seimtendinosus.


156


DESCHirTIVE ANATOMY.


’ A. SEMITENDINOSUS.

§ 1232. The semitendinosus muscle, Ischio-pretibial, Ch. (JVf. semitendinosus , s. seminervosus ), is an elongated muscle broader and thicker above than below, partially covering the following, because it is extended more below it and nearer the surface. It arises from the inner part of the posterior face of the sciatic tuberosity by a tendon which is very distinct outwardly, while its summit adheres very intimately to the inner edge of that of the long head of the biceps femoris muscle. This muscle is the most internal of the three flexors, and goes directly downward. Its lower tendon commences on its inner edge, a little below the centre of the fleshy belly ; from about the last fourth of the thigh it forms a very strong rounded cord, which passes behind the inner condyle of the femur to arrive at the tibia, and is attached, after enlarging and becoming thinner, to the inner face, directly below the gracilis muscle. It blends with the lower edge of the tendon of this latter muscle, and generally divides below into an upper and a lower slip.

We find a mucous bursa directly near its insertion, between its upper tendon and that of the semimembranosus and the long head of the biceps. There is also another, and sometimes two or three, even between its lower tendon ; that of the sartorius, that of the gracilis, and the internal lateral ligament of the knee.

This muscle bends the leg and turns it a little inward ; when it acts in an opposite direction it draws the pelvis and the trunk backward, and bends them with the thigh in the same direction.

B. SEMIMEMBRANOSUS.

§ 1233. The semimembranosus muscle, Ischio-poplili-tibial, Ch. (AT. semimembranosus ), follows a direction to a certain exent directly opposite to that of the preceding. Of the three flexors this arises farther forward, upward, and outward from the outer part of the sciatic tuberosity by a very long, strong, broad, and perfectly distinct tendon, which gradually enlarges and becomes thinner as it descends to the centre of the thigh and to the end of the fleshy belly, to which it is united by an edge oblique from within outward. This belly is elongated, rounded, thicker, but shorter than that of the semitendinosus, and is formed of an internal and an external layer of fibres which are turned upward towards each other, and are attached by radiations to the upper tendon. This latter exists only on the outer face of the upper part of the muscle ; but from its centre to its lower end, where it appears externally as a narrow band, it penetrates deeply inward to the centre of its substance. The lower tendon, which proceeds nearly to the centre of the muscle on its anterior face and on its inner edge, passes on the outer face of the inner condyle of the femur, between it and the semitendinosus


MÏ0L0GT.


157


musclej and is inserted to the inner part of the inner condyle of the tibia, after passing freely a short distance.

A mucous bursa exists between the upper tendon and the quadratus femoris or the adductor magnus. Sometimes there are two. Another is found between the lower tendon, the upper internal head of the gastrocnemius and the capsular ligament of the knee. This bursa often encloses another which is smaller, and adheres very intimately to the tendon of the semimembranosus muscle.

The action of this muscle is the same as that of the preceding.

II. BICEPS FEMORIS.

§ 1234. The biceps femoris muscle, Ischio-femoro-peronier, Ch. (JVJT. flexor cruris externus , s .fibularis, s. biceps femoris ), arises above by two separate heads, which are attached below by a common tendon.

The long head arises from the posterior face of the sciatic tuberosity by a short but firm tendon, which is inserted between the two preceding muscles. A short distance from its upper extremity this tendon begins to receive the fasciculi of the fleshy belly, and descends along its inner edge. The belly descends at first in a straight line, behind and at the side of the upper part of the semimembranosus muscle ; but it then goes outward, passes over the adductor magnus, and thus arrives at the outside of the thigh.

The short head is much smaller, and its form is an oblong square. It arises by very short tendinous fibres from the central two fourths of the outer lip of the linea aspera, directly at the side of the adductor magnus, goes obliquely downward, and is attached tothe inner face of the lower tendon of the long head, from the lower fourth of the thigh to near its lower end.

The common inferior tendon, which goes nearly to the centre of the large belly, on its posterior face, descends on the outer face of the outer condyle of the femur, and is inserted at -the top of the head of the fibula, where there is a mucous bursa between it and the external lateral ligament of the knee.

The biceps femoris muscle bends the knee, turns the leg a little outward, extends the pelvis, and inclines it slightly downward and backward.

§ 1235. Sometimes the short head does not exist, a remarkable analogy with animals, in most of which it is deficient. But in other subjects we find a third, which is thinner, and comes sometimes from the sciatic tuberosity, and is attached below the common tendon of the muscle,(l) and sometimes arises from the upper part of the long head, descends on the calf of the leg, and is joined by the lower end to the tendo Achillis ;(2) this deserves to be remarked because the biceps femoris muscle descends very low in the mammalia.

(1) Gantzer, loc. cit., p. 15. — Scenamering', Muskelehre, p. 276.

(2) Kelch, loc. cit., p. 42, no. xxxvi.


158


DESCRIPTIVE ANATOMY.


When this anomaly exists the biceps femoris resembles the normal structure of the biceps flexor cubiti, even as the latter, when it presents a third supernumerary head, represents the anomaly, of which the other sometimes gives an instance.


ARTICLE FOURTH.

MUSCLES OF THE LEG.

§ 1236. The muscles of the leg occupy its posterior, external, and anterior faces ; but they leave the internal loose, so that on this side the tibia is covered only by the skin. Most of them are attached, by their upper extremities, to the bones of the leg, and by their lowrnr, to those of the feet as far as the toes. Some, however, come from the lower part of the thigh, their lower extremities are inserted in the bones of the leg.

I. POSTERIOR MUSCLES.

§ 1 237. The posterior muscles of the leg form two layers, a superficial and a deep layer.

I. SUPERFICIAL LAYER.

§ 1238. The superficial layer of the posterior muscles of the leg is composed of two muscles, the triceps suræ and the plantaris.

A. TRICEPS SUBS.

§ 1239. The triceps suræ muscle {JM. triceps suræ , s. gemelli cum soleo) is extremely strong, and forms most of the muscular mass of the leg ; it deserves to be considered as a separate muscle with three heads, since these heads, although entirely separated above, are all attached below to a common tendon.

Two of these heads are in pairs and the third is single. The first two called for this reason the gastrocnemii muscles, Bi-femoro-calcaniens , Ch. (JM. gemelli suræ), are situated at the side of each other. They arise by a short, broad, but thin tendon, which terminates above by a semicircular convex edge from the femur, above the upper edge of the posterior face of its inner and outer condyle.

These two bellies are triangular and much narrower above than below. Above there is an interval of about four inches, which is filled by an abundant and very loose cellular tissue and also by the vessels and the nerves of the leg. Their fibres converge from above downward and meet the common tendon a little above the centre of the whole length of the muscle. The upper tendon, which is expanded along


MYOLOGY.


159


the external edge and the posterior face, gradually becomes thinner and descends almost to the lower extremity of the fleshy belly. The latter terminates below in a rounded edge ; so that the two bellies unite and form a waved line, very concave in its central part. The inner belly is much stronger and descends much lower than the outer. The lower tendon, in which the two fleshy bellies are inserted, arises far above their anterior face, that which corresponds to the posterior face of the bones of the leg, from the union of the two bellies to the centre of their common lower edge : it forms a broad canal, through which • pass the branches of the nerves and vessels which descend on the posterior face of the loose portion of the common tendon.

The third belly, called also the solans muscle, Tibio-calcanien, Ch., is much stronger than the two preceding. It is situated below and before them.

It arises by its upper edge, which is fleshy, serrated, and oblique downward and inward, from the posterior part of the head of the fibula, from the lower edge of the poplitæus muscle, and from the posterior edge of the tibia. Its lower edge and a part of its anterior face arise for a considerable distance above from the posterior face and below from the inner edge of the tibia. Finally, its outer edge comes from the upper part of the posterior face and from the outer edge of the fibula.

Its posterior and upper fasciculi go directly downward. The anterior and inferior of the two sides meet each other below and are attached to the anterior face of the common tendon, covering its anterior face to some inches above its insertion, gradually becoming thinner and narrower, so that this belly consequently occupies nearly all the leg, and descends very much lower than its centre.

The tendons by which the two lateral edges of this muscle arise from the fibula and the tibia gradually enlarge, descend on the anterior edge and on the posterior face, and do not stop except at some’inches above the lower end of this fleshy belly. Hence most of the latter is enclosed between two aponeurotic expansions.

The common inferior tendon, called the Achilles tendon ( tendo Achillis ), from its power, is slightly covered above and behind by the two posterior bellies and before by the third belly. A little above the lower edge of the posterior bellies it divides into an anterior and a posterior tendinous layer. The latter reascends on the anterior face of the gastrocnemius in the manner mentioned above : the other covers the posterior face almost to the upper edge, gradually becoming thinner.

The tendon, considered as a whole, contracts very much from above downward, and also becomes thicker, and is attached by a very narrow edge to the upper part of the posterior face of the tubercle of the calcanéum, between which and its anterior face we find a considerable mucous bursa above its insertion.

The triceps extends the foot in raising the heel : hence why it acts principally in standing on the toes and other similar circumstances.


160


DESCRIPTIVE ANATOMY.


When the foot is fixed, the two upper heads bend the knee and r draw the thigh backward and downward. The lower head, when it contracts toward the heel, extends the foot, because it carries the leg downward.

This muscle corresponds to the supinators and to the pronator quadratus of the fore-arm : the two superficial heads represent the supinators and the deep head is analogous to the pronator.

B. PLANTABIS.

§ 1240. The plantaris muscle, Petit femoro-calcanien, Ch., arises by a short tendon from the posterior face of the external condyle of the femur, from the external head of the gastrocnemius muscle, to which it is united, and from the posterior wall of the synovial capsule. Proceeding directly behind the capsule, it goes inward and downward and even becomes a long, thin, and flat tendon, which descends along the inner edge of the tendo Achillis, unites with it below, and disappears in the cellular tissue on the inner face of the calcanéum to arrive at the tendinous expansion of the sole of the foot.

This muscle has no very manifest action. We see in it only a rudiment of that which is much more developed in some mammalia and an imperfect imitation of the palmaris brevis of the hand.

§ 1241. It is often deficient and much more frequently than the palmaris.(l)

II. DEEP LAYER.

§ 1242. The deep layer of the posterior muscles of the leg is composed of the poplitæus, the tibialis posticus, the flexor longus digitorum communis, and the flexor longus pollicis proprius.

A. POPLITÆUS.

§ 1243. The poplitæus muscle, Femoro-popliti-tibial, Ch. (J\I. poplitœus , s. sub poplitæus), is a triangular muscle, which arises from the inferior and posterior part of the outer face of the external condyle of the femur. It is formed of oblique fibres, becomes broader from without inward, and is attached to the upper part of the posterior face of the tibia. It is intimately connected, especially at its upper and outer part, with the posterior wall of the synovial capsule of the knee. We find a mucous bursa between it and the external condyle of the femur on one side, the external semilunar cartilage and the capsular ligament on the other.

(1) Our observations authorize us to assert that Gantzer mistakes in stating that the plantaris is more constant than the palmaris (toe. cit., p. 4).


MYOLOGY.


161


This muscle corresponds to the pronator teres of the fore-arm.

It turns the leg a little inward, draws the outer semilunar cartilage outward and backward, and contributes to bend the knee.

§ 1244. Sometimes it is double.(l)

S. TIBIALIS POSTICUS.

§ 1245. The tibialis posticus muscle, Tibio-sous-tarsien, Ch. (AI. tibialis , s. tibiÅ“us posticus , s. nauticus ), arises between the extensor digitorum communis longus and the flexor longus pollicis pedis (§ 1248). It is the longest of the three muscles of the deep-seated lajmr and is penniform. It arises in its whole length from most of the posterior face of the interosseous ligament and from the inner face of the fibula ; some fibres of its upper part arise also from the outer part of the posterior face of the tibia.

Even as in the two long flexors of the toes, the two layers of fibres are attached to a very strong tendon, which descends inward and forward, is contained within the posterior and fibro-cartilaginous groove of the internal malleolus, thence passes into an analogous groove hollowed along the upper part of the inner face of the astragalus, and thus goes to the inner and lower face of the sole of the foot, opposite thd anterior part of the inner face of the astragalus. Its tendon incloses a rounded sesamoid bone and divides into two slips : the internal is shorter, the inferior is longer.

The first is single and is attached to the inner edge of the scaphoid bone. The second divides into several bands, which are inserted in the lower face of the scaphoid, the cuboid, and the three cuneiform bones, at the same time that they blend with the aponeurotic expansion of the sole of the foot and with the tendon of the peroneus longus.

The tendon of this muscle is surrounded with a mucous sheath where it arrives at the sole of the foot.

This muscle corresponds to the radialis internus muscle (§ 1149).

It extends the foot, turns its inner edge a little upward, and the sole inward ; it also extends the thigh and draws it backward.

C. FLEXOR LONGUS DIGITORUM COMMUNIS.

§ 1246. The flexor longus digitorum communis muscle, Tibio-plialangettien , Ch., (AI. flexor digitorum communis longus , s. perforons, s. profundus ), is a thin, elongated, and penniform muscle ; it arises from the summit of the anterior face of the tibia, except its upper part, which is covered by the poplitæus. The fasciculi, by which it arises, and which converge downward are inserted in a strong tendon below, which ascends almost to the upper extremity of the muscle and proceeds along the inner edge. This tendon approaches the surface, descends on the


(1) Fabricius, De motu loculi animalium, in Op., p. 359.

Vol. II. 21


162


DESCRIPTIVE ANATOMY.


posterior face of the tibia, goes to the inner face of the tarsus, and enters a fibro-cartilaginous furrow which exists along the upper part of the inner face of the astragalus, and is there kept in its position by a tendinous sheath, and thus goes forward. After leaving this point it turns outward, is covered by the posterior head of the abductor pollicis pedis muscle, on which it continues to go forward, and soon divides into fouibands, which go in their turn on the flexor digitorum brevis, which is consequently covered by it.

At the place where the tendon of the flexor longus muscle passes on the flexor brevis, and before it divides into four bands, we see a small muscle attached to its external and inferior part. The form of this muscle is an oblong square. It may be called the small or accessory head of the flexor longus communis {accessorius perf or antis).

This small head, which is covered on all sides by the flexor communis digitorum brevis, arises by two slips, the posterior or external, which is longer and stronger and comes from the external anterior tuberosity of the calcanéum, and the anterior or internal, which is smaller and arises from the superficial calcaneo-cuboid ligament (§ 982). Its fibres are oblique. It goes forward and inward, and not only is it fitted by its inner edge to the tendon of the flexor digitorum longus, but contributes much by its anterior tendons to form those of this muscle.

The small head principally forms almost the whole tendon of the second toe. Most usually this tendon is not at all derived from that of the slip of the common flexor, but only from the short head and from the tendon of the extensor longus proprius pollicis, with which the centre of the flexor communis communicates near the anterior extremity of the calcanéum.

The tendons of this muscle have the same relation to those of the short flexor as those of the flexor digitorum sublimis have with those of the flexor profundus. They are situated upon them, perforate them above the second phalanx of the toes, enlarge a little, and are attached to the posterior part of the lower face of the third phalanges.

It is surrounded by a mucous sheath in the place where its tendon passes at the side of the fibula and of the calcanéum. A second envelops this tendon and that of the flexor longus pollicis proprius at the posterior extremity of the sole of the foot.

The tendon it gives to each toe and that of the flexor minimi digiti proprius are surrounded with a proper mucous sheath.

This muscle bends the third phalanx of the toes and brings the leg backward.

§ 1247. Sometimes it is furnished with a fifth tendon, which replaces the fourth of the flexor digitorum brevis, which is then deficient. This tendon proceeds along the inner edge of the fourth tendon of the flexor longus, and divides to allow the latter to pass, and consequently presents the same arrangement as the flexor sublimis.(l) This formation


(1) Brugnone, loc. cit., p. 176.


MYOLOGY.


163


evidently resembles that of the apes, in which the tendons of the flexor sublimis and flexor profundus are so blended that they are distinguished from each other with difficulty.

D. FLEXOR LONQUS POLLICIS FKOPHIUS.

§ 1248. The flexor longus pollicis proprius muscle, Peroneo-sousphalangettien du pouce, Ch. (JVI. flexor hallucis longus), is shorter but much stronger than the preceding. It arises by an internal and an external layer of fibres, which converge downward and proceed by fleshy fibres from almost all the lower half of the posterior face and from the outer edge of the fibula, excepting only its lowest portion. These two orders of fibres are inserted in a strong lower tendon, which mostly remains concealed in the midst of the muscular substance and becomes entirely loose only when its fleshy fibres cease. This tendon goes obliquely from without inward and from behind forward, and thus comes on the inside of the tarsus, whence it goes forward along a fibrocartilaginous groove, which exists at the upper part of the inner face of the calcanéum, directly below the upper edge of this bone, and where it is retained by a special sheath. It is covered by the outer slip of the posterior head of the abductor pollicis pedis muscle and directly by the tendon of the flexor communis digitorum longus which is nearer the surface, and is consequently situated beneath it. It crosses the direction of the latter and sends to it a very strong tendon, which unites principally to that of the second toe.

We may justly say that the tendon of the flexor longus pollicis proprius muscle divides into two slips where it passes under the abductor pollicis pedis, an external for the second toe and an internal for the large toe. The latter is the strongest ; it goes inward and forward directly at the side of the abductor pollicis pedis, is situated outward before it, and is partly covered by it. At the anterior end of thé metatarsal bone of the large toe it enlarges a little, at the same time becomes thinner, and is attached to the posterior part of the lower face of the second phalanx of the large toe.

This muscle corresponds to the flexor longus digitorum communis in its course and in its attachment to the anterior phalanx of its toe.

There is in fact a short flexor of the large toe ; but this muscle has no perforated tendon which is attached to the posterior phalanx. On the contrary, we sometimes see an arrangement analogous to that of the tendons of the flexor brevis perforatus. In fact a strong but narrower tendon, which however gradually enlarges as it advances, extends from the head of the first metatarsal bone to the posterior end of the second phalanx, over the tendon of the flexor longus : this tendon is firmly attached in its whole extent and breadth of its upper face to the lower face of the phalanges, by a fold of the synovial capsule : it contains a single and transverse sesamoid bone : immediately behind its anterior extremity and below the articulation of the first phalanx with


164


DESCRIPTIVE ANAT0MV.


the second, it is finally attached to the lower face of the first phalanx, directly behind the tendon of the flexor longus.

This tendon which has no muscle, is not found in the other toes ; so that decidedly we should consider it as a rudiment of the flexor longus communis perforatus : it is however but an imperfect rudiment, since it is never perforated, which depends probably on the absence of the second phalanx of the large toe.

The tendon of this muscle is enveloped with a mucous bursa in the canal of the astragalus and os calcis. A second covers its tendon and that of the flexor longus at the posterior part of the sole of the foot. A third incloses its tendon along the metatarsal bone of the first toe.

It flexes the large and small toe.

§ 1249. We sometimes find at the lower part of the posterior face of the leg a small supernumerary muscle, which does not always present exactly the same arrangement. Sometimes it ascends from the calcanéum and from the tendo Achillis, and is attached to the aponeurotic expansion of the leg, acting as its tensor muscle ;(1) so that we may then consider it as a fourth head of the triceps. It sometimes arises from the lower part of the fibula, goes downward, and is then lost around the articulation of the foot. It is sometimes attached to a special bone found in this place, (2) or to the lower face of the calcanéum, or finally to the small head of the flexor longus digitorum communis. (3)

The second anomaly is very probably a repetition of the pronator quadratus of the upper extremity, but it is developed lower toward the foot, in accordance with the same law as that to which the other muscles are subjected, especially the flexors and extensors of the toes.

The first corresponds probably to the palmaris brevis ; the arrangement of the muscle in the upper and lower extremity differ in the same way as the palmaris brevis and the plantaris, as the latter does not arrive at the aponeurotic expansion of the sole of the foot.

II. EXTERNAL MUSCLES.

§ 1250. The external muscles of the leg are the peroneus longus and the peroneus brevis. They extend from the fibula to the outer edge and to the lower face of the foot.


I. PERONEUS LONGUS.

§ 1251. The peroneus longus muscle, Peroneo-sous-tarsien, Ch. (JM. 'peroneus longus, s. primus, s. posticus ), arises from the upper and smaller half of the anterior face, and by fibres which proceed obliquely from above downward and converge. Its upper tendon arises from the outer edge of the fibula and covers the upper and posterior part of this bone.

(1) Mayer in Heymann, loc. cit ., p. 15.

(2) Rosenmüller, loc. cit., p. 8.

(3) Gantzer, loc. cit., p. 15-17.


JMYOLOGY.


165


The lower tendon, which is very long, very strong, flat, and entirely loose from the lower third of the leg, conceals itself partially above this point between the muscular fibres ; so that it entirely disappears externally toward the bottom of the upper third of the leg. But it appears again within the muscle, near its upper extremity, as a semicircular band, which gradually diminishes and to which the fleshy fasciculi are attached outward and inward.

This tendon goes behind and on the outside of that of the peroneus brevis, along the outer and posterior face of the leg, and descends behind the external malleolus across a ligament formed of oblique fibres, within which is a sheath which sends prolongations to it. Arrived at the foot, the tendon winds forward and downward, 'around the outer edge of the cuboid bone, and thus comes on the sole of the foot, where it penetrates ; thence it goes inward, covered by all the muscles of this region and directly by the calcaneo-cuboid ligament, which keeps it in place : then gradually enlarging, it is attached to the lower face of the cuboid bone and also to the lower face of the posterior head of the fifth, also of the fourth and third, and particularly of the second metatarsal bones : it sometimes also reaches the first metatarsal bone and the first cuneiform bone before dividing.

At the place where the friction of the tendon is the greatest, especially opposite the external malleolus, the tuberosity of the calcanéum, and the cuboid bone, sometimes also in its plantar portion, we find sesamoid bones or cartilages, the third of which is the largest, while the first is very small and often scarcely perceptible.

There is also a considerable mucous bursa where the tendon of the muscle descends on the outer malleolus and astragalus : this bursa envelops it and also the tendon of the following muscle. We find another below, which extends to the plantar face.

The peroneus longus muscle extends the tibio-tarsal articulation and chaws the foot backward and the leg downward : it also turns the foot, making its outer edge the upper and the plantar face look upward.

It corresponds to the flexor carpi ulnaris of the fore-arm.

II. PEEONEUS EEEVIS.

§ 1252. The peroneus brevis muscle, Grand peroneo-sus-metatarsien, Ch. (JV[. peroneus, s.fibidaris brevis, s. anticus, s. secundus, s. médius, s. semifibulÅ“us ), is an elongated muscle, which terminates above in a point and is formed of two layers of fibres ; those of the anterior layer go from before backward and those of the posterior go from behind forward, These two layers converge toward the base : they arise from the second fourth of the anterior face and from the posterior edge of the fibula to near the outer malleolus.

The lower tendon, which is long, strong, and flat, extends within the muscle, and like that of the preceding ascends almost to its upper extremity. It becomes visible externally sooner than that of the pero

166


DESCRIPTIVE ANATOMY.


neus longus, and descends between the fibres of the muscle to arrive

at its outer face.

Once disengaged it goes before that of the peroneus longus, behind the outer malleolus, and is retained in the groove which exists there by a ligament, common to it and the preceding muscle. This ligament, called the retinaculum musculorum peronÅ“orum, extends from the anterior to the posterior edge of the groove like a bridge. The tendon having thus reached the upper face of the foot goes forward, enlarging along its anterior edge. Near the base of the fifth metatarsal bone it usually divides into two slips, the outer of which is attached to the tuberosity of this bone while the inner is longer, subdivided likewise into two parts, one of which is attached to the centre of the upper face of its body ; the second is inserted partly in the outer edge of the fourth tendon of the extensor and partly on the posterior face of the fourth external interosseous muscle.

Besides the common mucous bursa (§ 1229) the tendon of this muscle has a special bursa situated lower on the outer edge of the foot, and which surrounds it.

The peroneus brevis muscle acts like the preceding ; it flexes the tibio-tarsal articulation, consequently carries the foot upward, and depresses the leg ; it also turns the sole of the foot outward and its outer edge upward, but less so than the peroneus longus.

It corresponds to the extensor carpi ulnaris, and paitially also to the extensor brevis minimi digiti.

§ 1253. It is sometimes double.

III. ANTERIOR MUSCLES.

§ 1254. On the anterior faco of the leg we find one after another the extensor longus digitorum communis, the extensor longus hallucis proprius, and the tibialis anticus.

I. EXTENSOR LONGUS DIGITORUM COMMUNIS.

§ 1255. The extensor longus digitorum communis muscle, Peroneosus-p halange men commun , Ch. ( AI. extensor digitorum communis longus ), is a very long muscle, occupying almost all the leg. Its fibres descend obliquely from behind forward. It arises above from the outer face of the head of the tibia, and, in the rest of its course, from the anterior face of the interosseous ligament, and also from the anterior edge of the fibula. It is attached to the tendon which commences near its upper extremity and which descends on its anterior edge.

This tendon generally divides below the crucial ligament of the foot into five slips, which separate from each other. The outer is the shortest, and is inserted into the posterior extremity of the upper face of the fifth, and sometimes also of the fourth, metatarsal bone. This slip is sometimes connected with a special fleshy belly entirely distinct


MYOLOGY.


167


from the extensor longus, but which most generally forms only the lower part, and which is called the small or the peroneus iertius muscle. It is not unfrequently deficient, and is then replaced to a certain extent by the inner part of the tendon of the peroneus brevis muscle : it also frequently forms a small special tendon which is sometimes attached forward to the metatarsal bone, and sometimes unites either to the fourth external interosseous muscle or to the tendon sent by the common extensor to the fifth toe. The four other slips go obliquely forward and outward ; they are attached to the dorsal faces of the second, third, fourth, and fifth toes. Arrived at the base of the posterior phalanges they become broader and a little thinner, and give off also, the fourth outwardly, the other three inwardly, a thin triangular prolongation, formed of perpendicular fibres, which go downward, and are attached partly to the base of the first phalanx, and are partly blended with the tendon of the interosseous muscles.

This tendon sometimes assumes the nature of cartilage when passing over the synovial capsule of the first phalangean articulation. On the articulation between the second and third it enlarges or divides more or less completely into two lateral slips, which converge forward, and after muting are attached to the upper face of the third phalanx, directly before its posterior edge.

We find an oblong mucous bursa on the articulation of the foot, between the tendon of this muscle and the capsular ligament.

The extensor digitorum communis longus raises the four smaller toes, extends them, and with the peroneus brevis muscle, bends the tibiotarsal joint, and thus raises the foot or draws the leg forward and downward.

This muscle and the preceding act principally in standing on the toes, because they fix the leg.

The extensor digitorum communis longus corresponds to the common extensor of the fingers. The proper extensor of the little finger is represented by the peroneus tertius, and when that is deficient by a part of the peroneus brevis.

This analogy becomes still more evident when the portion of the flexor longus belonging to the little toe, and the peroneus tertius muscle, are entirely separated from the rest of the muscle.(l)

II. EXTENSOR LONGUS HALLUCIS EROPRIUS.

§ 1256. The extensor longus hallucis proprius muscle, Peroneo susphalangettien du pouce , Ch., is a thin and semipenniform muscle, which arises, by fleshy fibres, from the lower two thirds of the inner face of the fibula, and from the anterior face of the interosseous ligament. It also receives below some fibres from the outer face of the tibia.

Its fasciculi are attached to a tendon which proceeds along the anterior edge of the muscle, gradually becomes broader, passes across a particular groove of the crucial ligament of the back of the foot, goes


(1) Brugnone, loc. cit . — We have seen it several times.


168


DESCRIPTIVE ANATOMY.


inward and forward along the inner edge of the tarsus, and is attached to the upper face of the unguæal phalanx of the first toe.

On the back of the tibio-tarsal articulation the tendon of this muscle is inclosed in a special mucous sheath.

It raises all the first toe.

§ 1257. This muscle is often more or less completely double. In this case we sometimes find another which is smaller, and which arises more externally from the fibula, and from the anterior face of the interosseous ligament, goes to the large toe, and unites to the tendon of this muscle, or is attached to the first metatarsal bone, or finally loses itself in the cellular tissue. Sometimes and most generally another smaller tendon is detached, even in the leg, from the inner edge of the normal tendon, which is inserted in the tibial side of the two phalanges. These anomalies are important because they approximate the formation of the proper extensor of the large toe to that of the proper extensor of the thumb ; so too on the other hand, the deficiency of the short extensor of the thumb, or its blending with the large, approximates the formation of the hand to that of the foot.

III. TIBIALIS ANTICUS.

§ 1258. The tibialis anticus muscle, Tibio-sus-tarsien, Ch. (JVT. tibialis, s. tibiczus anticus, s. catena: musculus, s. hippicus), is the strongest of the three anterior muscles of the leg ; it arises directly at the side of the peroneus longus muscle, and is covered in this place by a broad tendon, which expands on its anterior face from the lower face of the outer part of the head of the tibia, and still lower from the outer face of this bone, nearly to its lower third, so that its fibres gradually come only from the most posterior portion, and even the inner edge of this face in all its course. At the same time it receives some which arise from the periosteum. All these fibres, which go obliquely Torward, are attached to an anterior tendon, which is loose only in a very small point of its extent downward, but which extend within the muscle even beyond its centre. This tendon, which is very strong, descends obliquely inward, passes on the anterior face of the tibio-tarsal articulation, comes upon the inner edge of the foot, where it is retained by a ligamentous band, oblique downward and backward, which extends from the scaphoid to the first cuneiform bone, and is finally attached by two short slips to the inner part of the lower face of -the large cuneiform bone, and also to the base of the metatarsal bone of the large toe.

Opposite the articulation of the foot its tendon is enveloped in a mucous sheath.

It raises the foot, turns it on its axis, so that its sole looks inward and its inner edge upward.

It corresponds to the radiales muscles of the hand.


MYOLOGY.


169


ARTICLE FIFTH.

MUSCLES OF THE FOOT.

§ 1259. The muscles of the foot arise from the tarsus and metatarsus, and are all attached to the phalanges of the toes. They are situated on the back of the foot, on its sole, on its internal and external edges. Some are common to several toes, others belong exclusively to some of them, namely to the large and small toes. The latter are only repetitions of those which are divided between several of them.

I. MUSCLES OF THE BACK OF THE FOOT.

§ 1260. Besides the tendons of the extensor digitorum communis longus and of the two peronei muscles, we find also on the back of the foot the extensor communis digitorum brevis.

EXTENSOR COMMUNIS DIGITORUM BREVIS.

§ 1261. The extensor communis digitorum brevis muscle, Calcaneosus-phalangettien commun, Ch. ( JW, . extensor digitorum pedis communis brevis, s. pediceus externus ), is a flat muscle, formed of four elongated and rounded bellies, which arises from the back of the anterior process of the calcanéum, goes forward and inward, its bellies separating from each other, and is attached -by four tendons to the four inner toes. These tendons in their course on the metatarsus cross those of the extensor communis digitorum longus, but on the toes they are situated on the outside of them. The outer three are very intimately blended, by their internal edge, with the outer edge of the tendons of the extensor longus, and consequently form their outer half ; hut the most internal, that which goes to the great toe, does not unite to the corresponding tendon of the flexor longus, but is attached below it to the posterior edge of the back of the first phalanx of the large toe.

This muscle extends the four inner toes and directs them a little outward.

§ 1262. Often and even most generally its inner belly is separated much more from the others than the latter are from each other. Very frequently it forms an entirely distinct muscle, which deserves to be noted because of the more striking resemblance established between the upper and lower extremities by this peculiarity. Sometimes the other bellies and even all are entirely detached from each other, a curious analogy with what exists in birds. Again, the extensor brevis often presents supernumerary bellies. Most commonly a small fleshy fasciculus exists between the internal and what is commonly called the second ; its tendon is attached either to the second metatarsal bone or to the tibial face of the second toe. This accessory muscle, men Vol. II. 22


170


DESCRIPTIVE ANATOMY.


tioned by Albinus,(l) and which we have often seen, is curious, as it must evidently be considered as a repetition of the indicator muscle.

The second belly is also sometimes divided at its anterior extremity into two fasciculi, or sends two tendons to the second toe.

The tendons of the third and fourth bellies are often divided, so that there is for the third toe an extensor muscle or at least a tendon ; this arrangement resembles the doubling of the proper extensor of the index finger in the hand for a proper extensor of the third finger.

After this anomaly the one most frequently found consists in the presence of a small special belly for the fifth toe. We have also seen this several times, and it is interesting as an analogy either with the apes(2) or with the extensor proprius minimi digiti.

II. MUSCLES OF THE SOLE OF THE FOOT.

§ 1203. Most of the muscles of this part of the lower extremity are found in the sole of the foot.(3) In fact, besides the short head of the extensor digitorum communis already described (§ 1245), we find the flexor communis digitorum brevis, the adductor and flexor of the large and little toes, the adductor hallucis, the lumbricales, and the interossei muscles.

The adductor hallucis occupies the inner edge of the foot and that of the little toe the outer edge. A great part however of these muscles project likewise in the sole, so that it is best to study them at the same time as the other muscles of the toes, to which they belong, and to consider them as the lower muscles of the foot.

We shall describe first the common muscles, next the special muscles : first, however, their common aponeurosis.

I. PLANTAR APONEUnOSIS.

§ 1264. The plantar aponeurosis (aponeurosis plantaris) is a very firm tendinous layer, formed of longitudinal fibres, which arises from the lower face of the tuberosity of the calcanéum, directly under the skin, with which it is intimately connected. Thence it goes forward, where it enlarges very much. Arrived at the anterior edge of the metatarsus it divides into five slips, which correspond to the five toes, and which are attached to each other by transverse fibres.

This aponeurosis protects and fixes the muscles of the sole of the foot, and at the same time increases the surfaces of insertion of several.


(1) Hist, muse ., p. 602.

(2) Meckel, Beytrâge zur vergleichenden Anatomie, vol. ii. part i.

(2) A. F. Walther, Tractationes de articules , ligamentis et musculis incessu dirigendis supplemcnlvm tahulamquc novam plantœ humani pedis exhibens, Leipsic, 1731.— D. C. de Courcelles, Icônes musculorum plantœ pedis, sorumque descriptio, Au-isterdam, 1760.


MYOLOGY.


171


II. COMMON MUSCLES OF THE SOLE OF THE FOOT.

a. Flexor dig-itorum pedis communis brevis.

§ 1265. The flexor communis digitorum brevis muscle, Calcaneosous-phalanginicn commun , Ch. (JV/. flexor digitorum pedis communis brevis , s. perforahis , s. sublimis, s. pediœus intermis ), is elongated, quadrilateral, thicker behind, and broader but thinner before. It arises by very strong tendinous fibres, which extend on a considerable portion of its lower face from the lower face of the tuberosity of the calcanéum, and by fleshy fibres by almost all its lower face, from the upper face of the plantar aponeurosis, to which its posterior tendon also adheres. Posteriorly it is very intimately united internally with the outer edge of the adductor pollicis, and above with the short head of the extensor communis digitorum longus. Nearly in the centre of the sole of the foot it divides into four very short fleshy fasciculi, which soon become as many single tendons. The latter are attached to the second, third, fourth, and fifth toes. They cover those of the extensor longus and are much smaller. They are arranged in the same manner anteriorly as those of the extensor digitorum sublimis. In fact a rhomboidal fissure begins a little before the posterior extremity of the first phalanx, which extends to before the centre of this bone. The tendons of the extensor communis digitorum profundus pass through these fissures.

The two halves of the tendon which pass through this division unite for a short extent ; then again separate, enlarge and diverge from before backward, and are separately attached by straight edges to the centre of the lower face of the second phalanx.

Each tendon of this muscle is attached with the corresponding tendon of the flexor longus, to the lower face of the toes by synovial and fibrous ligaments, exactly like those which retain the tendons of the flexor sublimis and profundus of the fingers.

This muscle flexes the first and second phalanges of the four outer toes.

§ 1266. The fourth tendon is sometimes deficient, and then it is often but not always replaced by a tendon of the flexor longus. In some subjects there seems to be an antagonism between the short extensor and the short flexor of the toes ; for we have sometimes found in this case the number of tendons of the second is greater than usual.

Sometimes also another portion of the muscle is deficient ; it is usually the most internal or the most external. It is then replaced by other fasciculi which come from the flexor of the large and that of the little toe, which reminds us of the insulation of the internal head of this muscle hi apes, and the disappearance of the short common flexor as a separate muscle in all the other mammalia and in all birds.


172


DESCRIPTIVE ANATOMY.


b. Lumbricales.

§ 1267. The lumbricales muscles, Planti-sous-phalangiens , Ch., correspond to those of the hand in number, form, and situation. They arise by fleshy fibres from the tendons of the flexor digitorum longus, and are attached, partly by short tendons, to the posterior head of the first phalanx of the four outer toes, and partly by thin tendinous expansions, to the tendons of the extensor digitorum longus.

c. Interossei.

§ 1268. We find in the foot as in the hand seven interossei muscles, Æetatarso-phalangiens latéraux , Ch. (JVf. interossei), which fill the intervals between the metatarsal bones. They arise from the posterior part and from the lateral faces of these bones, and their anterior tendons blend below with those of the extensor communis.

We distinguish them into external and internal. The first are four and the second three in number.

a. External interossei.

§ 1269. The upper and external or dorsal interossei muscles (JM. interossei externi , s. superiores, s. dorsales) are situated directly below the extensor communis digitorum brevis, in the first, second, third, and fourth interosseous spaces.

The first, which is the most internal, differs from the other three in its form and arrangement. In fact it comes only from the tibial side of the second metatarsal bone and is attached forward by a short, broad, and flat tendon to the inside of the first phalanx of the second toe.

It is however almost always divided into tw r o heads, the upper of which is longer and much thinner than the lower.

The second, third, and fourth have two heads each, which are inserted by short tendons on the outer or fibular side of the first phalanx of the second, third, and fourth toes.

The outer head is much larger, arises from the posterior part of the inner face of the metatarsal bone, which is placed directly on the outside of the toe to which the tendon is attached, and descends as deeply as the internal, on the side of the sole of the foot. The inner is the smallest, and arises from the posterior part of the outer face of the metatarsal bone of the toe in which its tendon is inserted, and descends a little lower than the preceding. The fibres of these two heads unite at a very acute angle and are implanted in a common tendon.

The first external interosseous muscle brings the first toe inward ; the second, third, and fourth carry the toes to which they are attached outward.


MYOLOGY.


173


b. Internal interossei.

§ 1270. The internal, inferior , or plantar interossei muscles (JVf. interossei interni , s. inferiores , s. plantares) are smaller than the external and have only one head. They arise from almost all the posterior part of the inner or tibial face of the third, fourth, and fifth metatarsal bones, and are attached by a considerable tendon to the inner face of the first phalanx of the third, fourth, and fifth toes. This tendon is closely united to the capsule of the metatarso-phalangean articulation, and sends a prolongation to that of the extensor communis.

These muscles direct the third, fourth, and fifth toes inward toward the large toe.


III. PROPER MUSCLES OP THE TOES.

§ 1271. We may consider as proper muscles those of the large and small toes.

a. Muscles of the large toes, a. Abductor haltucis.

§ 1272. The abductor hallucis muscle, JWetatarso-sous-phalangien du premier orteil , Ch., is the strongest short muscle of this toe. It arises by several slips from the inside of the tarsus and the metatarsus, and is attached to the inside of the large toe. To simplify the description, we may refer these several slips to two heads.

The posterior head, which is the larger, arises by two bands, of which the inferior is longer, from the lower part of the inner side of the tuberosity of the calcanéum, and the upper, which is shorter, from the upper and projecting part of the inner face of the body of the calcanéum.

The anterior head, which is the smaller, arises by three or four distinct slips from the inner and anterior face of the astragalus, scaphoid, the first cuneiform, and first metatarsal bone. The posterior tendon of these two fasciculi covers them from their origin to near their anterior extremity below. The anterior, which is much stronger, begins near the centre of the posterior belly and is situated on its inner side ; so that the fibres of the two bellies which go forward and inward are inserted at acute angles.

This last tendon, after it disappears from the surface, extends very far within the muscle, whence it goes backward and divides into several very considerable slips. Anteriorly, it is sometimes attached by two slips to the lower and inner face of the head of the first metatarsal bone, to the inner face of the capsular ligament of the first metatarso-phalangean articulation, and principally to the inner and lower


174


DESCRIPTIVE ANATOMS'.


part of the base of the first phalanx of the large toe, where it adheres intimately to the flexor digitorum brevis.

This muscle brings the large toe inward and flexes it a little.

b. Flexor brevis pollicis pedis.

§ 1273. The flexor brevis pollicis pedis , Tarso-sous-phalangien du premier orteil, Ch. {JS1. flexor hallucis proprius brevis), is much shorter than the abductor. It arises behind from the tendinous sheath of the peroneus longus, intimately united to the long'head of the adductor of the large toe. Most generally its posterior extremity maybe divided into an external and an internal belly. Thence it goes inward and forward. It is attached by a short tendon, more or less divided, to the posterior part of the lower side of the base of the first phalanx of the large toe. This tendon is generally united to that of the adductor outward ; it contains anteriorly, below the two parts of the head of the first metatarsal bone, two sesamoid bones placed one at the side of the other.

This muscle flexes the first phalanx of the large toe.


c. Adductor pollicis pedis.

§ 1274. The adductor pollicis pedis muscle, Calcaneo-sous-phalangien du premier orteil , Ch. (JM. adductor hallucis), is a considerable muscle which has two bellies.

The posterior is much stronger than the other and is placed above and outside of the flexor brevis pollicis pedis. It arises from the lower side of the base of the third and fourth and also often of the second metatarsal bone, and from the sheath of the peroneus longus, above the flexor brevis pollicis pedis. Before, on its outer and lower face, are strong tendinous expansions, which unite to give rise to the anterior tendon. This latter is united to the external tendon of the flexor brevis (§ 1212), and is attached to the outer face of the base of the first metatarsal bone.

The anterior head is much smaller and weaker than the posterior, and arises from the lower and inner face of the capsular ligament, between the metatarsal bone and the first phalanx of the fourth and fifth toes, sometimes also from the anterior part of the fifth metatarsal bone.

It goes obliquely forward and inward, directly below the anterior end of the interossei muscles, between these and the tendons of the flexor communis digitorum profundus. It is attached by a thin and short tendon to that of the abductor of the great toe.


MYOI.OGY.


175


b. Muscles of the little toe. a. Abductor minimi digit!.

§ 1275. The abductor minimi digiti muscle, Calcaneo-sous-phalangenien du petit orteil , Ch. (JVf. abductor digiti quinti), is the longer of the two muscles of this appendage, has two bellies like the abductor pollicis pedis ; the posterior belly is greater.

The posterior belly is covered below and behind by a strong aponeurosis, and arises from the posterior and from a little of the anterior part of the lower face of the tuberosity of the calcanéum.

The anterior belly comes from the lower edge of the tuberosity of the fifth toe.

Both are attached outwardly to a broad and strong tendon, which extends far back into the substance of the muscle and which is attached to the outer part of the lower face of the base of the first phalanx.

b. Flexor minimi digiti brevis.

§ 1276. The flexor minimi digiti brevis muscle, Tar so-sous-p hal angien du petit orteil , Ch. (AI. flexor digiti quinti proprius brevis), is much smaller than the preceding. It arises from the inner part of the lower side of the base of the fifth metatarsal bone and from all the lower face of its body. It may almost always be divided into an outer and inner belly. Most frequently also it is attached by two distinct tendons to the inner part of the lower side of the base of the first phalanx.

§ 1277. The muscles of the large and small toes may be referred to the other muscles of the foot, as we have seen those of the thumb and little finger could be to the other muscles of the hand. The abductor pollicis pedis is the first external interosseous muscle, and the posterior belly of the abductor the first internal interosseous muscle. The anterior belly of the latter represents the first lumbricalis. The flexor brevis digitorum pedis muscle corresponds to the flexor digitorum communis. The abductor minimi digiti is the last external interosseous muscle. Finally, the flexor minimi digiti brevis may be considered as belonging to the flexor digitorum communis, because of the slight development of the fourth tendon of the latter in most subjects.

COMPARISON OF THE MUSCLES OF THE DIFFERENT REGIONS OF THE

BODY.

§ 1278. We have already compared the muscles of the different regions of the body with each other in different directions, while describing each one particularly. They also conform to the law that the analogy betweeen the upper and lower halves of the body is more marked than that between the anterior and posterior. In fact we observe, 1st, that many muscles which succeed from above downward


176


DESCRIPTIVE ANATOMY.


arc repetitions of one another, as is evident with those between the vertebrae or between these bones and the head ; 2d, the muscles of the limbs correspond very evidently, and the differences they present, like those between the bones and the ligaments, depend on the greater solidity of the lower limbs and the greater mobility of the upper, either when considered as a whole and in their relations with the trunk, or when viewed in detail and in regard to the relations of their different parts with each other. An abnormal arrangement of the muscles belonging to the two extremities frequently renders their similitude more perfect and more evident than it is generally ; and if we do not err, of all the organic systems, the muscular most frequently presents anomalies in the configuration, which cause an unusual similitude between the anterior and posterior faces of the body and also between its upper and lower portions.

In this respect we often find an anterior sternal muscle, which determines a resemblance between man and animals, and the existence of which is so curious in another respect ; and we not unfrequently find a short head of the biceps flexor cubiti and a short extensor of the middle finger.

So too the muscles of the lower limbs are frequently repetitions of those of the upper. The latter however seem to us more disposed to present assimilating anomalies in their configuration, which probably depends on a general law, amply supported by the vascular system, viz. that anomalies in the pelvic members are more frequent than in the pectoral extremities.

GENERAL REMARKS ON THE MOTIONS OF THE HUMAN BODY.

§ 1279. Having described successively the different organs of locomotion, we must now briefly examine the principal motions(l) which result from their joint action.

We must first, endeavor to prove that the erect •posture on the lower limbs is natural to man.


A. ERECT POSTURE.

I. OSSEOUS SYSTEM.

§ 1280. We may also point out in this place the conditions which arise from the other organic systems, not yet described, and which refer to the general form of the body, because the osseous system serves as the basis for all the others.

In considering the body from below upward, we discover successively in the osseous system all the conditions which render the erect posture natural to man.

(1) F. Roulin, Recherches théoriques et expérimentales sur le mécanisme des mouvements et des att itudes dans l'homme ; in the Journ. de physiol. e.rp., vol. i. p. 2C9, 301, vol. ii. p. 45, 156, 283.


MYOLOGY.


177


1. In the lower extremities.

§ 1281. 1st. The predominance of the bones of the lower over those of the upper extremities.

2d. It is only in the erect posture that the articular surfaces of all the bones are exactly fitted to each other.

3d. The breadth of the foot.

4th. The size of the tarsus and metatarsus in proportion to the toes.

5th. The number and size of the sesamoid bones.

6th. The union of the bones of the leg with the tarsus at a right angle.

7th. The length and the obliquity of the neck of the femur.

8th. The breadth, concavity, and lowness of the iliac bones.

2. In the trunk.

§ 1282. 1st. The lowness, breadth, and curve of the sacrum, and also the curving inward of the coccyx, upon which and also on the arrangement of the iliac bones the peculiar shape of the human pelvis depends, which seems well adapted only for the erect posture.

2d. The breadth and lowness of the vertebrae.

3d. The considerable curve of the ribs, whence results the breadth and convexity of the thorax.

3. In the head.

§ 1283. 1st. The anterior, posterior, and horizontal position of the condyles and foramen magnum of the os occipitis.

2d. The direction of the cavities of the orbits and nose forward in the erect posture and downward in that on the four limbs.

4. In the upper limbs.

§ 1284. 1st. The shortness and feebleness of these members in proportion to the lower.

2d. The forced position of the bones of the fore-arm and of the radiocarpal articulation in walking on all fours,

3d. The mobility of the radius.

4th. The concavity and breadth of the bones of the metacarpus and of the phalanges. These latter circumstances indicate that the bones of the upper extremities are intended to grasp external objects, while the corresponding parts of the lower limbs prove they are designed to support the body.


VOL. II.


23


178


DESCRIPTIVE ANATOMY.


II. LIGAMENTOUS SYSTEM.

§ 1285. The peculiarities of the ligamentous system are as follow :

1st. The ligaments of the lower extremities are stronger than those of the upper, and this strength increases progressively from below upward.

2d. The looseness of the cervical ligament, although the head is very much developed, in regard to the occipital foramen which is situated farther forward.

III. MUSCULAR SYSTEM.

, § 1286. The muscular system also furnishes several strong argu ments :

1st. The greater power of the muscles of the lower extremities.

2d. The extreme force and the arrangement of some of them, viz.

a. The thickness of the peronei muscles in the leg, the lower head of which always draws the leg backward arid extends it, whiie the upper two prevent the body from falling forward.

b. The arrangement of the flexors of the leg compared with that of the flexors of the fore-arm ; for one of the three long flexors of the first of these limbs is manifestly developed only in part ; so that the number of the corresponding muscles in the fore-arm is much greater than in the leg.

c. The thickness of the glutæi muscles, particularly the glutæus maximus.

d. The multiplication of the muscles of the fore-arm to execute the peculiar motions of the bones of the fore-arm : so likewise the difference between the number and development of the special muscles of the thumb and little finger and those of the large and small toes.

e. The deeper situation of several of the muscles' of the fore-arm in the upper extremity, and the foot only in the lower : such are particularly the flexor brevis and the extensor communis brevis.

f. The slight extent of the insertion of the flexors of the leg, which favors the extension of this limb and prevents the continued forced flexion it experiences in quadrupeds.

g. The smallness of the small muscles of the head, which, in connection with the looseness of the cervical ligament and the anterior position of the occipital foramen, forms a very striking character, especially when we regard the great development of these parts in quadruped the head of which is however smaller than that of man.

§ 1287. All these circumstances united prove sufficiently that the erect posture on the lower limbs is natural to man.

We must next examine how the erect posture is preserved in a state of repose, and how the body when erect exercises the motion of progression, or of standing and of â– walking, treating of the modifications of each.


MYOLOGY.


179


B. OF STANDING.

§ 1288. The trunk and the lower limbs act in standing. The part taken by the trunk consists,

1st. In the support of the head by the vertebral column.

2d. In the action of the very strong long muscles of the back which fill the channels between the vertebrae and the ribs. They prevent the body from falling forward, to which it is in some measure disposed from the portion of the pectoral and abdominal viscera before the vertebral column. In fact, they are much more developed in their lower part than at their summit. In this part also we feel fatigue and pain most sensibly after standing a long time and especially after leaning forward.

Tire trunk is supported by the lower extremities. Whenever the position changes the pelvis presents a broad point of support for its weight, and that of the head which is sustained by the vertebral column. The articulation of the ossa femoris with the iliac bones in front of their union with the spine increases the extent of this base of support.

In standing, the weight of the body passes from this base to the thigh, next to the leg, and finally to the foot, so that the body rests upon the latter.

In the usual p ition on the two feet, besides the peculiarities relative to the lower ex. . amities and which we have mentioned above, their separation caused by the breadth of the pelvis and the length of the neck of the thigh bones is very advantageous, as it increases the extent of the base of support which falls between the soles of the feet ; thus the attitude becomes unsteady and less firm when the breadth is diminished by approximating the feet.

Standing, inasmuch as it depends on the lower limbs, results’ from the action of all the muscles which arise from the trunk, and from the different sections of these members. These muscles contract from above downward, and thus move the divisions immediately above them, and act in a direction the inverse of that which results in progression, since they approximate the least movable point to that which is most movable. Thus the most active are, 1st, the gliitæi, which draw the trunk backward ; 2d, the three flexors of the leg, which prevent the pelvis from inclining forward ; 3d, the extensors of the thigh, excepting the rectus, which prevent the limb from falling backward ; 4th, the lower head of the triceps, suree, which keeps the leg on the foot in a direction intermediate between flexion and extension.

The other muscles, which confine the action of those we have mentioned, have little or no action, and this action is counteracted by that of the others.

Standing on one foot, where the whole weight of the body rests on one of the lower extremities, is practicable, especially by the length of the


180


DESCRIPTIVE ANATOMY.


neck of the femur and the breadth of the sole of the foot. This posture of the body is preserved by the action of the muscles on the outside of the lower limbs, by the broad abdominal muscles, and by the quadratus lumborum, which act from below upward, preventing the body from falling to the opposite side, where it is unsupported.

In standing on the toes there is no change except in the relations of the bones of the leg and the action of its muscles. The toes are extended as much as possible on the metatarsal bones and the foot on the leg, and the weight of the body then rests wholly on the toes and also on the sesamoid bones of the foot, which are numerous and large. This position is caused principally by the simultaneous action of the muscles situated on the anterior and posterior faces of the leg and foot ; the tibialis anticus, the peronei, especially the peroneus brevis, the extensors of the toes anteriorly, and the triceps suræ posteriorly, are the principal agents.

At the same time the toes are forcibly pressed against the ground by the action of their flexors, hence they are - more firmly fixed and afford a more solid point of attachment to their muscles.

C. OF WALKING.

§ 1289. Walking is produced by the displacement of the lower extremities, which move alternately either forward, backward, or laterally, so that a distance exists between them, and consequently the rest of the body is supported by only one of them. Each motion, by which a limb is raised from the ground, separated from the other, and is replaced on the ground, is a step.

This motion, in whatever direction it is performed, depends principally on the displacement of the femoral articulation, which is flexed in walking forward or sideways, and, on the contrary, extended in walking backward.

When we walk forward or backward the knee-joint is generally slightly bent, which serves to raise the foot still more. The metatarsophalangean joint is most generally forcibly extended, articular when the lower limb which is to be moved is behind the other; In walking, the flexion of the haunch carries one of the two limbs more or less before the other ; when left to itself, and the coxo-femoral articulation is not bent, the foot falls again to the ground and the step is finished. If we take long steps the pelvis also turns more or less around the limb which remains fixed as around an axis ; hence the limb which moves, and the corresponding side of the body, are carried farther forward. This effect is caused partly by the flexion of the other sections of this limb and partly by the extension of the metatarso-phalangean articulation.

It is merely necessary to mention these motions to know the muscles which perform them.


MYOLOGY.


181


Running is a quick walk, most generally withlarge steps, which differs from the ordinary walk not only by its rapidity, but also because all the lower face of the foot rests on the ground.

Jumping is a sudden movement by which the body rises into the air. In order to perform it all the joints of the lower limbs are flexed and then suddenly extended ; from the shock which the body experiences from the soil against which it strikes it is carried upward until its weight exceeds the motion communicated to it, and causes it to return to the earth.

The leap in a straight line is always shorter than the oblique leap because the weight of the body presents more resistance in the first case than in the second.

In kneeling the articulation of the foot is flexed by the anterior muscles of the leg, which act from above downward, and the articulation of the knee is changed in the same manner by the action of the upper heads of the triceps suræ muscle.

In stooping the gastrocnemii muscles of the leg exercise all their power ; at the same time the coxo-femoral articulation is flexed more or less forcibly in order to lean the body forward, and to prevent its centre of gravity from falling behind its base of support, and in this manner to prevent its fall.

§ 1290. The motions of the trunk{ 1) are very limited. This is proved by the vertebrae and also by the pieces of the sternum, which are firmly united. Thus the motions of the trunk in every direction depend but slightly on the displacement of the bones which form it, but almost entirely on the lower limbs, and those in the coxo-femoral articulation, are performed by the muscles which extend from the thigh and leg to the vertebral column and to the iliac bones. The mobility of the ribs is much greater ; the changes in their situation produce the continual alternate changes which take place in the capacity of the chest, and which result in inspiration and expiration. The examination of these changes and of those which occur in the capacity of the abdominal cavity will be more in place after describing the pectoral and abdominal viscera than here.

§ 1291. The head moves on the vertebral column ; it bends forward, is extended backward, inclines to the side, and turns on its axis.

The last two motions take place almost entirely between the second and first vertebræ, the last of which only accompanies the head. The other two occur between the head and the atlas, and not between the atlas and axis, because the odontoid process and the transverse portion of the crucial ligament almost entirely prevent every displacement in this direction between the first and second vertebræ.

Luxation cannot take place in flexion and extension on account of the firmness of the attachments ; but it easily supervenes in the rota (1) Winslow, Sur les mouvemens de la tête, du cou et du reste de l’épine du dos , in the Mém. de Paris, 1730, p. 492-503.


182


DESCRIPTIVE ANATCMY.


tion of the first vertebra and of the head on the axis, when this motion is performed quickly.

The cervical portion of the vertebral column must always be fixed in order that these different motions ma_y be executed.

§ 1292. The b upper limbs are much more movable than the lower both in regard to the trunk and their different sections, which doubtless depends on the arrangement of these bones and the ligaments. The motion of rotation on the axis particularly is much easier in the first than in the second. The greater mobility of the upper limbs, considered as a whole, is also increased by the difference remarked in the mode of articulation, of the first section of the bones of the two extremities, for the iliac bones are almost motionless on each other and on the vertebral column, while the clavicle and scapula on the contrary are very movable both on each other, and on the trunk.

Hence the motions of the upper limbs are not performed solely in the scapulo humeral joint as those of the lower extremities are in the coxo-femoral articulation, but take place at the same time in the scapulo- and sterno-clavicular articulations ; hence they are not only more free, but also keep the bones together in the different motions they perform. Hence the bones are much less firm, but they require less strength, since the upper extremities are rarely obliged to sustain such heavy loads as happens for instance in creeping, walking, or standing on the hands.

If we except the fingers and toes, mobility diminishes from the periphery of the limbs to their centres.

A great difference between the partial motions of the two limbs consists in the power of turning the radius on its axis and around the ulna while the leg cannot move around the thigh, except as a whole, the fibula being immovable on the tibia. The leg is capable only of flexion and extension, while the fore-arm can execute also the motions of pronation and of supination.Q I.)

Although in the two latter motions the radius is the principal part displaced, the ulna is not however motionless ; for it is slightly extended in pronation and a little flexed in supination.

(1) Winslow, Obs. anat. svr la rotation , la pronatiop, la supination et d'antres moiivcmens en rond, in the Mérn. de Paris, ÎV27, p. 25-33, — Vicq ci’Azyr, Œuvres, vol. V. p. 343-351.


ANGEIOLOGY.


183


BOOK IV.


ANGEIOLOGY.

§ 1293. The vascular system(l) is composed of a central part, the heart , whence all the blood departs and where all this fluid returns ; of vessels which carry it away, the arteries ; and of vessels which

(1) We have already mentioned (vol, i. p. 280) the most important works on the general conditions of the structure and external form of the vascular system in the normal and abnormal state. We shall now mention the principal descriptive treatises. They are,

I. Foe the whole system. — J. C. A. Mayer, Anatomische Beschreibung der Blutgefässe des menschlichen Körpers , Berlin, 1777, 1778. — F. A. Walter, Angiologisckes Handbuch, Berlin, 1789.

II. Foe the heart, — 1st. Complete description of this organ in all its parts, both in the normal and the abnormal state ; Senac, Traité de la structure du cÅ“ur, de son action et de ses maladies, Paris, 1747, 1778. — 2d. Complete description of it in the normal state ; R. Lower, Tractatus de corde, item de motu calore et transfusione sanguinis, London, 1669. — J. N. Pechlin, De fabrica et usu cordis, Kiel, 1676. — Winslow, Sur les fibres du cÅ“ur et sur ses valvules, avec la manière de le préparer pour le démontrer, in the Mémoires de Paris, 1711, p. 196, 201.— Vieussens, Traité de la structure et des causes du mouvement natural du cÅ“ur, Toulouse, 1711. — Santorini, Obs. anat ., Venice, 1724, ch. viii., Deiis quee in thoracemsunt . — Lieutaud, Obs. anat. sur le cÅ“ur, in the Mém. de Paris, 1752, 1754. — 3d. Development of the heart; Meckel, Sur l'histoire du développment du cÅ“ur et des poumons dans les mammifères, in the journal complém. du Diet, des sc. médic., vol. i. p. 259. — Rolando, Sur la formation du cÅ“ur et des vaisseaux artériels , veineux et capillaires, same journal, vol. xv. p. 323, vol. 16. p. 34. — Prévost et Dumas, Développment du cÅ“ur et formation du sang, in the Annales des sciences naturelles, vol. iii. p. 46. — 4th. Structure of the heart in respect to. the arrangement of its fibres ; C. F. Wolff, Dissertationes de ordine fibrarum muscularium cordis, in the Act. Acad. Petropol., 1780-1781, in the Nova act., vol. L-viii. — J. F. Vaust, Recherches sur la structure et les mouvemens du cÅ“ur, Liege, 1821. — S. N. Gerdy, Mémoire sur l'organisation du cÅ“ur, in the Journ. compl. du Diet, des sc. méd., vol. x. p. 97. — 5th. Pathological state ; A Burns, Observations on some of the most frequent and important diseases of the heart, London, 1809. — Pelletan, Mémoires sur quelques maladies et vices de conformation du cÅ“ur, in the Clinique chirurgicale, Paris, 1810, vol. iii. — Testa, Delle malattie del cuore, loro cagioni, specie, cura, Bologna, 1810, 1813.' — Corvisart, Essai sur les maladies et les lésions organiques du cÅ“ur et des gros vaisseaux, Paris, 1818. — Kreysig, Ucber die Herzkrankheiten, Berlin, 1814, 1817. — Laennec, De l'auscultation médiate , or Traité du diagnostic des maladies des poumons et du cÅ“ur, Paris, 1819, p. 195-445. — Bertin, Traité des maladies du cÅ“ur et des gros vaisscu. v, Paris, 1824.

III. For the arteries. — H aller, Icônes anatomicœ, Gottingen, 1745, 1756. — A. Murray, Descriptio arteriarum corp. humani tabulis redacta, Upsal, 1783, 1798. — J. F. S. Posewitz, Physiologie der Pulsadern des menschlichen Körpers, Leipsic, 1795. — J. Barclay, A description of the arteries of the human body, Edinburgh, 1818, 8vo. — Tiedmann, Tabulae arteriarum corporis humani, Carlsruhe, 1822, 1824. — Hodgson, Diseases of the arteries and veins.

IV. For the veins. — B esides the tables of Loder see Breschet, Sur le système veineux, now publishing.

V. For the Lymphatics. — T he works mentioned in the first volume contain also a description of this system.


184


DESCRIPTIVE ANATOMY.


return it, the veins and the lymphatics. The last mentioned carry a fluid different from the blood, they are the annexes or appendages of the venous system.

SECTION I.

OF THE HEART.

CHAPTER I.

GENERAL REMARKS.

§ 1294. The heart (cor) is a hollow muscle irregularly conical or pyramidal, situated in the centre of the chest, between the two lungs, and inclosed in a special envelop called the pericardium. Its vessels are numerous, but it has few nerves : it is formed of several cavities, some of which are separated, while others communicate together. Its tissue is formed of fibres united in superimposed layers, and is connected on one side with the large venous trunks of the lungs and body, and on the other with the large arterial trunks of both. Each of these characters deserves to be specially considered.

I. FORM.

§ 1295. The shape of the heart is that of a cone or an irregular pyramid. We distinguish in it a broad and thick base (basis) and a summit (apex), which is generally blunt and bifurcated, an upper and anterior face which is concave, and an inferior and posterior which is smaller and flatter ; two edges, a posterior which is thick and pointed, the anterior is smaller, shorter, thin, and sharp.

The base of the heart is formed, properly speaking, by that part of the organ directly connected with the veins : we may then term it the venous portion of the heart (pars cordis venosa). However we generally apply the term base of the heart to the upper region of the arterial portion. The venous portion is formed of two auricles. It is separated from the next by a large groove, called the groove of the base , the auricuto-ventricular groove , or circular groove ( sulcus baseos , s. alrio-ventricularis, s. circularis). Its form is an oblong square and its breadth exceeds its height.

The succeding portion, which is situated before the auriculo-ventricular groove, is directly connected with the large arterial trunks. We may then term it the arterial portion of the heart (pars arteriosa cordis). It is formed by the two ventricles. It terminates in a blunt summit, which is usually more or less evidently grooved. This groove is sometimes very large.


ANGEIOLOGY.


185


The longitudinal groove (sulcus cordis longitudinales superior et inferior) exists on both faces of the heart, from its base to its summit, and consequently in all its length.

The principal branches of the nutricious vessels of the organ are situated in these grooves : they communicate on the side of the base by a groove, which descends perpendicularly between the two auricles, and on the summit by the depression observed in this place. They mark the course of the septum within the heart (septum cordis).

§ 1396. The septum passes also across the venous portion of the heart or the auricles as well as its arterial portion or the ventricles. It separates completely these two synonymous parts, and consequently divides the heart into a right or an anterior and a posterior or left half. That part which passes between the auricles is called the septum atriorum, and that between the ventricles is called the septum ventricidorum. The right part of the heart is called the pulmonary heart (cor pulmonale), because the pulmonary artery arises from it, or the heart of the black blood, from the color of this fluid within it. The left is termed the aortal heart (cor aorticum ), because the aorta arises from it, or the heart of red blood, from the color of the blood within it. We employ sometimes also the terms of first ventricle, to designate the anterior, and second ventricle, to mark the posterior ; but these are less convenient.

II. WEIGHT AND SIZE.

§ 1297. The weight of the heart in a fully grown man is about ten ounces ; whence it is to that of the whole body as 1 is to 200.

Its length, measured from the centre of the auricles, is between five and six inches its mean length is five and a half inches, four of which are for the ventricles and one and a half for the auricles. The breadth of the ventricles united is generally three inches at their base and that of the auricles is three and a half inches. (1 )

III. SITUATION.

§ 1298. The heart is placed obliquely from right to left, from behind forward, and from above downward ; so that its base is nearly opposite

(1) A knowledge of the perfectly normal proportions of the heart in the healthy state is very important to the physician, since without it he can establish no certain diagnosis of the diseases of the central organ of the circulation. We cannot do better than to quote the following passage of Laennec on this subject : “ The heart, in cluding the auricles, should be equal to, a little less, or a little larger than the first of the subject. The walls of the left ventricle should be a little more than twice as thick as the walls of the right ventricle ; they should not collapse on cutting into the ventricle. The right ventricle, a little larger than the left, presenting- smaller fleshy pillars, although its parietes are thinner, ought to collapse after the incision.” (De V auscultation médiate, vol. ii. p. 270.) “Reason teaches and observation proves, that in a well formed subject the ca\ ities of the heart are nearly equal ; butas the parietes of the auricles are very thin and those of the ventricles are much thicker, it follows that the auricles form only one third of the whole volume of the organ or the half of that of the ventricles.” ( lb .) ~ F. T.

VOL. II.


24


1S6


DESCRIPTIVE ANATOMY.


the eighth dorsal vertebra, from which it is separated by the esophagus and aorta, and its summit corresponds to the cartilage of the sixth rib, or to the interval, which separates it from the next. Its lower face, which is flattened, corresponds to the upper face of the central tendon of the diaphragm, and the upper to the central and left portion of the anterior wall of the chest.

IV. TEXTURE.

§ 1299. The heart is formed of several layers of muscular fibres, situated between two thin, smooth, and polished membranes, the inner and outer membranes of the heart. The latter is the inner layer of the pericardium.

The outer surface of the heart is smooth and uniform in relation to the inner, even when we have removed the outer membrane.

The inner surface is very uneven and reticulated, which arises from its being formed of numerous rounded, flat, and distinct muscles, which intercross continually and which are called fleshy •pillars ( trabeculœ carneœ). The mnscular substance of the heart is generally harder, more solid, and more elastic than that of other muscles.

As the arrangement of these fibres(l) differs wholly in the venous portion from what it is in the arterial portion, as it is not exactly the same in the right and left portions, and as it finally differs according to the subject, all that can be said generally may be reduced to the following corollaries :(2)

1st. The directions of the layers are more or less opposite. But in the recent state, far from being entirely separated from each other, they intercross differently ; so that all those of one portion of the heart constantly contract uniformly and diminish the cavity they circumscribe in every direction.

The union of the different layers takes place partly by more or less manifest muscular fibres.

2d. The fibres which form the layers are united in fasciculi of various sizes, which vary more or less in their origin and their direction, and which are often separated by greater or less spaces. These fasciculi are sometimes rounded and sometimes flattened, — a difference which seems to depend on determinate laws, since it is constant in the different regions of the heart. For instance the right and left ventricles

(1) Wolff, De online fibrarum muscularium cordis, diss. vii. De stratis fibrarum in Universum. In nov. act. petrop., vol. iii., 1785, p. 227-249. — Gerdy, loc. cit., p. 101. — Vaust, loc. cit., p. 102, etc.

(2) Gerdy has established a law, that all the fibres, whatever is their extent, situa tion, and direction, form webs, which are convex toward the point of the heart, and which are nearly superficial at one extremity and deep at the other ; so that for instance the external or internal fibres are the same reversed, and having passed through the thickness of the ventricle. The extremities of these muscular webs are constantly inserted in the base of the heart, around the different auricular'and arterial orifices of the ventricles, either directly or by tendons attached to the auriculoventricular valves (loc. cit., p. 101). F. T.


ANGEIOLOGY.


1S7


are not similar in this respect nor in regard to the arrangement of their fibres, and the same is true of other parts also. Thus the inner layers are generally rounded and form fleshy pillars. The auricular appendages of the auricles are formed of rounded fasciculi, and the auricles of flattened fasciculi.

From this arrangement we may deduce that the firmest parts are formed of rounded fasciculi. But the fibres and the fasciculi formed by them are united by intermediate fibres, which may be distinguished with facility.

The fibres and fasciculi are every wdrere interlaced with each other, conformably withall the in voluntary muscles. They are united principally in two ways : sometimes the ends of the fibres and fasciculi join, and sometimes they are united by intermediate filaments, which arise from their lateral portions.

In the first case, either the fasciculi go to meet each other and the extremities of those which continue together intermix like the teeth of a saw, as is the case with the digitations of several adjacent muscles, or some fibres are attached obliquely to others at acute angles, as the fibres of the penniform muscles are implanted in their tendons, and finally, as is the case most generally, the fibres or fasciculi which go side by side unite at very acute angles.

The lateral union takes place principally between the insulated fibres and the small fasciculi of fibres, especially in the outer layer. Sometimes it is irregular ; so that those fibres which are evidently separated in the rest of their course are placed one against another in a part of this same course, whence the reticulated structure is more or less evident. It is sometimes regular, and we see oblique fibres going from each side, which unite. The redness and determinate form of the intermediate filaments always demonstrate that they are not formed of cellular tissue but of real muscular substance.

The mode in which the filaments are united also presents determinate differences in the different regions of the heart.

3d. In the ventricles, the external layers go obliquely downward, backward, and from right to left. The direction of the central is opposite, and the most internal, which form the fleshy pillars, extend longitudinally from the summit to the base.

On the contrary, the transverse direction predominates in the auricles. The external layer, which is the strongest, proceeds in this direction, while the internal, which forms only insulated fasciculi, has a longitudinal direction.

4th. All the external layers are not equally extended. Generally the external layers are those only which cover all the surface of the ventricles ; the central are smaller and occupy only a third of the heart. If we except the most internal, that which forms the fleshy pillars, they diminish in direct ratio to their depth. They disappear first at the summit of the organ, and in reascending from this point to the base of the ventricles, they are deeper and deeper ; so that the deepest


ISS


DESCRIPTIVE ANATOMY.


arc found only at the base. Hence this part of the heart is the thickest.

We observe also occasional spaces between the layers, which extend the whole length or all the breadth of the ventricles.

5th. The outer layers differ from the central ones, inasmuch as they are stronger and their fibres are more intimately united together.

Thus the fibres and the fasciculi of the inner layers are more easily demonstrated. But the external forcibly embrace and compress these latter ; so that they contribute essentially to the firmness of the heart.

6th. The fibres of the two portions of the heart are not continuous, at least not all of them, with each other, so that the same layers are reflected on the two ; but the fibres of the two ventricles terminate in the septum. The upper and lower faces of the heart are not arranged in precisely the same manner : the separation is seen with more difficulty in the first than in the second. We remark also three different arrangements in the upper face. In fact, either we cannot distinguish the least trace of separation and the fibres are uninteruptedly continuous with each other, or two fibres are in fact applied one on the other, but a species of suture serves as a line of demarkation between them, or finally they mingle with each other by digitations.

Wolff states that on the lower face, the fibres of the two ventricles are separated by a distinct and very broad band, formed of longitudinal fibres, and which diminishes insensibly from the base to the summit, to which these fibres are attached on the two sides. But we have usually found but a slight, and often no trace of this arrangement.

7th. The upper extremities of the fibres of the heart are attached to a fibro-cartilaginous tissue,(l) formed

a. Of two oblong, rounded projections or tubercles, usually three or four lines long, little less than a line thick, seen on both sides of the orifice of the aorta.

b. Of a thin band, which surrounds the posterior part of the circumference of the aorta and unites the two tubercles.

c. Of four filaments, placed in the circular groove on the base of the heart, two on the right and two on the left, an anterior and posterior on each side. Below these four filaments the two anterior arise from the tubercles. The right anterior goes into the anterior and upper part of the circular groove ; the left into the upper and posterior part. The posterior two arise by a very short common trunk, which is only a few lines long, from the band which unites the two tubercles, near that of the right side, and proceed in an opposite direction to the lower part of the circumference of the circular groove.

These anterior and posterior filaments are situated at the venous orifices of the ventricles. They do not surround the base of the heart

(1) C. D. F. Wolff, Dc or dine fibr arum muscularium cordis , Diss. ii., de textu cartilagine ocordis , sivc dcfilis cartilagineo-osseis corumque in basi cordis distribution. In Act. Petropol., 1781, vol. i. p. 211. — Gerdy, loc. cit., du tissu albugine cardiaque , p. 97.


A NGEIOLOGY,


189


and form a complete ring, but terminate near the edges of each orifice and gradually lose themselves in the cellular tis'sue.

This cartilaginous tissue is surrounded entirely by a thin, firm, but loose sheath, a real perichondrium. It is covered more externally by the outer membrane of the heart and internally by its inner membrane.

The external muscular or superficial fibres arise principally from the cartilaginous tubercles and filaments, and from the cellular tissue between the extremities of the latter ; so that the fibres, which come from the tubercles and from the origin of the filaments, adhere to them very intimately, while the others are united only by a cellular sheath which surrounds them.


v. vessels. (1)

§ 1300. The blood-vessels of the heart are proportionally very large and are called the coronary vessels ( vasa coronaria cordis). The coronary arteries and veins resemble each other in many respects :

1st. These vessels (the arteries) arise directly from the beginning of the trunks of the vessels of the body, or they (the veins) open directly into the heart.

2d. They turn around the base of the heart in the circular groove, whence they send toward the summit large branches which arise at almost right angles : these go to the ventricles and proceed along the heart, while the others are smaller and follow an opposite direction, proceeding to the auricles.

3d. The large trunks and the large branches extend on the outer face of the organ and ramify internally.

4th. The veins have valves at the places where they open but not in their course. There are two arteries of nearly equal calibers, while we find only a single large coronary vein, which is constant ; but beside this last we observe several, which are smaller, which open 'directly into the heart, but not constantly, except into the right part of the organ, and particularly into the right auricle : they do not open, even, except into the septum, and they do not empty their blood into the left part of the heart, (2) as some anatomists have pretended, and among others Vieussens(3) and Thebesius.(4) In fact, Abernethy has very recently supported this latter opinion, viz. that the venous blood of the heart mixes with the arterial blood which nourishes the body, without passing through the lungs ; he has only modified it by saying, that these orifices of the coronary veins in the left portion of the organ serve principally to prevent repletion of the right portion in those cases where the passage of the blood through the lungs is obstructed ; because,

(1) Haller, De vasis cordis propriis, Gottingen. 1737. — Iterates observationes, 1739. — Geisler, Commentatio de sanguinis per vasa coronaria cordimotu, Leipsic, 1743.

(2) Sabatier, Sur les veines de Thebesius ; in the Traité d’anat., vol. iii.

(3) Nouvelles découvertes sur le cœur, Montpelier, 1706. — Traité du cœur, 1715.

(4) De circula sanguinis in corde, Leipsic, 1708. — De circulo sanguinis per cor , Leipsic, 1759.


190


DESCRIPTIVE ANATOMY,


having injected the cardiac arteries and veins in a subject whose lungs were diseased, he has seen the fluid penetrate into the left ventricle by broad openings. But as generally injections, even when very fine, transude on all the inner face, although no venous orifices are perceptible on the left side, we have reason to admit that the openings existing in the cases observed by Abernethy were produced accidentally, either during life or after death, by obstacles to the course of the injection, on account of the feeble resistance of the tunics of the veins weakened by disease, and considerably distended, both by the blood accumulated in these vessels and by the injected mass.

VI. NERVES.

§ 1301. The nerves(l) of the heart are proportionally smaller than those of the voluntary muscles. They arise from the upper and lower cervical ganglions of the great sympathetic nerve, from the cervical portion of the nerve between these two ganglions, or from the central ganglion sometimes found in this place. Some arise directly from the nerve, others from the plexuses formed by the filaments which come from the ganglions and by others sent off by the pneumo- gastric nerve.

The relations of the nerves of the heart with its muscular substance have been the subjects of dispute. Some anatomists, Behrends(2) among others, deny that this substance, and consequently that the heart, possesses nerves, which they pretend are distributed only to the cardiac vessels. Others on the contrary, as Scarpa, Munniks,(3) and Zeirenner,(4) maintain that they really go to the heart as well as to all other muscles.

The partisans of the first hypothesis adduce the following arguments :

1st. Anatomical examination, whence it results that the cardiac nerves, which we cannot follow except to the third ramification of the coronary arteries, do not enter the substance of the heart but go only to the arteries. (5)

2d. The origin of the cardiac nerves ; they arise from the great sympathetic nerve, the ramifications of which go only to the arteries. (6)


(1) J. F.. Neubauer, Descriptif) nervorum cardiacorum, Frankfort and Leipsic, 1772. He has figured the nerves of the right side. — E. P. Andersch, De nervis ; in the Nov. comm. GÅ“tt ., vol. ii., and Königsberg, 1797. He has represented those of the left side. These figures have been copied in Haase, Cerebri nervorumque corporis humant repetita, Leipsic, 1781. — A. Scarpa, TabulÅ“ neurologicæ ad illuslrandum historiam anatomicam cardiacorum nervorum cerebri , glossopharyngÅ“i et pharyngæi ex octavo cerebri, Pavia, 1794.

(2) J. Behrends, Diss. qua demonstratur cor nervis carere, additâ disquisitione de vi nervorum arteriös cingentium, Mayence, 1792.— A. T. N. Zerrenner, An cor nervis careat iisque carere possit? Erford, 1794.

(3) Observationes varice. Diss. auat. med., Groningue, 1805, 1-17.

(4) Zerrenner, An cor nervis careat iisque carere possit ? Erford, 1794.

(5) Behrends, loc. cit , p. 5, 8.

(6) Id., ibid., p. 8.


ANGEIOLOGY.


191


3d. The smallness of those nerves which is in direct ratio with the thinness of the fibrous coat of the arteries,(l) and which contrasts on the contrary with this law, that the number and size of the nerves correspond to the power and frequency of the motions of the muscles.^)

4 th. The insensibility of the heart, the motions of which are independent of the nervous system, since it beats regularly although removed from the body, (3) and the excitement of the nerves, whether mechanically or dynamically, by means of galvanic electricity, do not alter its motions, (4) and its pulsations are not deranged when the nervous system is paralyzed as in apoplexy. (5)

5th. The integrity of the motions of the heart, notwithstanding the administration of opium. (6)

But all these arguments can be refuted with greater or less facili'y. In fact :

1st. The manner in which the cardiac nerves are distributed and their proportion both to the muscular substance and to the vessels, do not differ essentially from what is seen in the same respects in the voluntary muscles. (7) Here also the nerves and the ramifications of the vessels are very compactly situated in regard to each other, and we do not see the nerves unite to the muscular substance. Besides the cardiac nerves are closely connected with the vessels only in their largest branches, and not at all in many animals.

2d. The muscular substance of the heart is only a greater development of the fibrous membrane of the vascular system, so that the distribution of the branches of the great sympathetic nerve within it does not present an aberration from the type of this nerve.

3d. The cardiac nerves possess more medullary substance than those of the voluntary muscles. They arise from the ganglions of the great sympathetic nerve, and through them from ail the _ spinal marrow. Their action is probably favored by the mutual contact of the blood and of the inner face of the heart ; very probably also the size of the nerves which go to the voluntary muscles relates to their functions which is to conduct the influence of the will.

4th. The facts cited in the fourth paragraph are explained partly by the smallness and partly by the texture especially the softness and gelatinous nature of the cardiac nerves, and from the circumstance that they arise from the ganglions. Besides they are correct only to a certain extent, since the motions of the heart are not entirely independent of the nervous system. The passions have a marked influence on the number and strength of its pulsations. Impressions of

(1) Behrcnds, loc. cit., p. 8, 9.

(2) Id., ibid., p. 10.

(3) Id., ibid., p. 11.

(4) Id., ibid., p. 20.

(5) Id., ibid., p. 12.

(6) Id., ibid., p. 11.

(7) Scarpa, loc. cit., § 13. — Munniks, loc. cit., p. 6.


192


DESCRIPTIVE ANATOMY.


every kind on the nervous system modify its motions more or less sensibly.(l)

In fact several observers, particularly Valli, Volta, Klein, (2) and Bichat, have doubted the influence of electricity on the motions of the heart; but the observations of Fowler, Schmuck, Pfaff,(3) Rossi, (4) Giulio,(5) Humboldt, (6) Munniks,(7) and Nysten, and our own also, prove it to be real.

The non-affection of the heart in paralysis of the brain proves nothing' in regard to the relations between the nerves and this organ, since the irritability of the voluntary muscles is not altered in apoplexy. This apparent difference depends only on that between the excitants of the voluntary and involuntary muscles. In fact the excitant of the first is the influence of the brain, and that of the second the substance contained in their cavity, which in the present case is the blood. The motions of the heart continue also in cerebral paralysis, while those of the other muscles are not performed ; the activity of these last seems extinct while it is only no longer seen.

5th. The observations of Haller, of Fontana, of Whytt,(8) and of Alexander, (9) prove that the heart, like the voluntary muscles, is sensible to the influence of opium, whether the narcotic acts directly upon it, or is placed in contact with the nervous system or with any organ whatever. These observations and experiments prove that the relation between the heart and the nerves is perfectly like that between the nerves and muscles generally, and more, because the effect of opium upon the heart is much more evident when this substance is placed in relation with the nervous substance than when applied directly to the heart.


VII. VENOUS PORTION.

§ 1302. The characters of the venous for lion of the heart, (10) the auricles, are,

1st. The muscular substance of its parietes is so thin that the two membranes of the heart touch in several places.

2d. Its form is irregularly quadrilateral.

(1) See on this subject Legallois, Experiences sur le principe de la vie, Paris, 1812, . — Wilson Philip, in the Phil. Trans ., 1815, part i. p. 65-97 ; part ii. p. 224-246. — Ici. An experimental inquiry into the laws of the vital functions, London, 1818.

(2) In Pfaflf, Vcber thicrischc Electricitât und Reizbarkeit, p. 119.

(3) In PfaflF, loc. cit., p. 140.

(4) Mém. de Turin , vol. vi.

(5) Voig’ht, Magazin , vol. v. p. 161.

(6) Ueber die gereizte Muskel-und Nervenfaser , vol. i. p. 340-349.

(7) Loc. cit., p. 115.

(8) In Pfaffj loc. cit., p. 140.

(9) Memoirs of the Manchester society, vol. i. p. 98.

(10) Ruysch, Epist. anat. problemala décima de auricularum. cordis earumque fibrarum molricium structura, Amsterdam, 1725. — A. F. Walther, De structura cordis auricularum, Leipsic.


ANGEIOLOGY.


193


3d. It is composed of a part into which the veins open directly the cavity of the auricle , the sac (sinus), and another upper and anterior, the auricular appendix (auricula), which projects above the sac.

The exact limits of these two parts cannot be pointed out, or rather anatomists do not distinguish them according to the same principles on the right and left sides. On the left side the appendix is readily distinguished from the sac, because it suddenly forms a very rounded projection, which is much narrower, and has thicker walls on the upper anteiior and left angle. On the right side, on the contrary, this name is applied to a part, the walls of which are very thick, which is formed on the left by the confluence of the two venæ eavæ, terminates above in a blunt summit, and which is not sensibly separated from the rest, while, if we remained true to the analogy, this term should be applied only to the small appendix which terminates the auricle above, and which is elevated on the left along the vena cava superior.

4th. It is directly continuous with the venous trunks which open into it.

VIII. ARTERIAL PORTION.

§ 1302. The characters of the arterial portion of the heart, the 'ventricles, are,

1st. Their parietes are thicker, so that the internal and the external membranes are every where separated from each other by a muscular substance. The thickness of the parietes of each portion of the heart is then in direct ratio with the extent passed through by the blood it sends forward.

2d. The arterial portion is considerably larger and broader than the venous portion.

3d. Its external form is elongated, rounded, and pyramidal, and determines, properly speaking, the form of the whole heart.

4 th. At its upper extremity are two openings, the venous and the arterial, which establish the communication, the first between the ventricle and the auricle, and the second between the ventricle and the artery w hich arises from it. The venous orifice is almost perpendicular ; its direction is from before backward and from right to left ; the arterial is almost horizontal and is situated a little above the former farther inward and nearer the septum.

Both are rounded j the venous is broader than the arterial. Its form is elliptical, while the latter is nearly circular.

Neither the venous nor the arterial opening is perfectly loose ; both have valves. The valves placed at the arterial opening are very similar in their arrangement to those found in the common veins they are however much larger and are usually three in number. Thenconvex and attached edge looks toward the heart while the loose edge, which has two concavities and which is thicker than the rest of the membrane, is turned toward the cavity of the artery. In the centre

Vol. II. 25


194


DESCRIPTIVE ANATOMY.


of the latter we observe a fibro-cartilaginous tubercle ( nod-ulus ). The blood which comes from the ventricle pushes them toward the circumference of the artery and against its parietes. On the contrary the blood which tends from its specific gravity to return from the artery into the ventricle separates them from these same parietes, their loose edges then touch, and they form a horizontal septum between the cavity of the artery and the ventricle, which prevents the reflux of the blood into the latter. The tubercles complete this septum and close the space in the centre of the artery between the three valves.

The valves of the venous orifice differ from those of the arterial opening, and from all other valves, since they are attached much more firmly, hence they close more completely the opening around which they are placed. A narrow cartilaginous ring, which is not however perfect, exists on all the circumference of the venous opening ; this sometimes ossifies in advanced age, especially in the left portion of the heart, and is situated deeply between the muscular fibres of the ventricle and those of the auricle.

This is the cartilaginous tissue already described as the origin of the external muscular fibres of the heart. The venous valve is attached to this tissue by its posterior edge, but its opposite and uneven edge, unlike that of all the other valves, is not loose ; many flat and solid tendinous filaments, which extend from the base to the summit of the heart, arise from the valve, on which they are often united or pass over it and go to the opposite part of the circumference of the heart, soon unite into larger cords, and are attached to the parietes of the heart, and principally to its fleshy pillars. As the latter shorten when the heart' contracts, the different parts of the valves then approach each other and the opening is forcibly closed. It is necessary that the loose edge of these valves should be thus attached since they must resist not only the weight of the blood like the other valves, but also the action of the muscular parietes of the heart, which forcibly push forward the arterial blood.

5th. The arterial portion of the heart is divided into an upper and lower half, which are separated by the upper part of the valve of the venous orifice at the upper and posterior parts of the ventricles, and which blend together at the summit of the heart, so that the ventricles, although resembling externally an elongated cone, form in fact two arched canals, convex forward, and the greatest convexity of which corresponds to the summit, and are more extensive in this part than in any other.

6th. The reticulated structure of the ventricles is much more distinct than that of the auricles. Some of the fleshy pillars form rounded, elongated projections, terminating in blunt summits (musculi papillares ), which go toward the base of the heart, and from the extremity of which several tendinous filaments proceed to attach themselves to the loose edges of the venous valves. Farther, those fleshy pillars which are attached by their two extremities, as well as those which have


r


ANGEIOLOGY.


195


one end loose, communicate with each other at intervals by tendinous fibres. The direction of the principal fasciculi is longitudinal, the smaller which unite the preceding are oblique. Near the summit the reticulated texture is more and more developed, and the parietes become thinner in the same proportion.

IX. RIGHT AND LEFT PORTIONS.

§ 1303. 1st. The right half of the heart is considerably thinner than the left. This difference is very striking between the two ventricles, where the relation is generally as one to four or to five. Even then we find, as between the auricles and the ventricles generally, that the power of the parietes is in direct ratio with the space passed through by the blood winch comes from them. The greater thickness of the walls of the left ventricle determines the form of the whole arterial portion of the heart. The right wall formed only by the septum is convex, and the left appears fitted to it like a sling.

2d. The substance of the right side, especially that of the ventricle, is softer and looser than that of the left side.

3d. The right side is broader than the left after death.(l) This difference also is most marked between the two ventricles, but it is not yet determined if it exists constantly during life or supervenes only after death.

Many anatomists, particularly Lower, (2) Santorini, (3) Weiss, (4) Lieutaud,(5) and Sabatier, (6) have adopted the latter opinion, while most others favor the first.

This hypothesis has been supported sometimes by the result of measurement, and sometimes by the fact that the left ventricle is as much longer as the right is broader, and sometimes by experiments and observations, from which it has been concluded that the right side appears broader after death, only because it is more distended by the blood which remains stagnant in the lungs from their inaction, while previously the passage of the blood from the left ventricle was not obstructed ; whence the left ventricle seems to be narrower compared to the right, in proportion to the less quantity of pulmonary blood received by it through the pulmonary veins. In men and animals who have died suddenly from the injury of the large vessels, or of those which communicate with the right portion of the heart, when consequently this cause of the distention of the right ven (1) Helvétius, Sur l’inégalité de capacité qui se trouve entre les organes destinés à la circulation du sang , dans le corps de l’homme, et sur les changemens qui arrivent au sang enpassant par le poumon, in the Mêm. de Paris, 1718, p. 222-281.

(2) Loc. cit., p. 34.

(3) Loc. cit., p. 144, 145.

(4) De dextro cordis ventriculo postmortem ampliore, Altdorf, 1745.

(5) Essais anat., p. 230, 231.

(6) Sur /’inégale capacité des cavités du coeur et des vassieaux pulmonaires, in the Mém de Paris.

(7) Lieutaud has brought forward this argument.


196


DESCRIPTIVE ANATOMY.


tricle did not exist, the capacity of the two portions has been exactly or nearly the same.(l) Finally, when the left ventricle is placed in the same condition by means of a ligature as is the right ventricle at the time of death; while on the contrary the blood is removed from the latter by cutting the pulmonary artery, or the vena cava, we find that the relation between the two ventricles is the inverse of that which commonly exists, that is, that the right ventricle is narrower than the left.(2)

The vein's appear much larger than the arteries after death, undoubtedly from the same cause.

To these experiments we may add that we sometimes find the right ventricle narrower than the left from the effect of disease, such as ossification or some other malady of the valves of the aorta, in which case the difference must be explained precisely in the same manner. We have before us several preparations in which, beside a considerable dilatation of the left ventricle arising from this cause, there is at the same time a great contraction of the right ventricle, proving that the results drawn from these facts cannot be opposed, by saying that the dilatation of the right cavity of the heart in the usual state of things should extend also to the left portion from the influence which it exercises on the veins and arteries of the body, and consequently that the right half is really larger during life since the left is itself distended. Since the cause of the greater distention of the right portion, that is, the more difficult passage of blood through the lungs, supervenes only at the moment of death, the opinion that the right ventricle is also more capacious during life cannot be sustained. (3)

That the cause above mentioned is that which increases the capacity of the light portion of the heart at the period of death only, is proved by the fact that the difference between the two portions of the organs varies with the cause of death, and that it increases in a direct ratio with the increase of the obstacle to the circulation of the blood in the lungs. Thus, in those animals killed by drowning, hanging, and suffocation, Colman has found the right ventricle generally twice the size^of the left, although its proportions commonly mentioned are much smaller.(4) In fact, Haller asserts that in one subject he found it three times as large as the left, (5) but the usual estimates are much less than this. Gordon says the relation is sometimes as 5 : 4,(6) Lieberkühn as 3 : 2,(7) Portal as 7 : 5,(8) Helvetius(9) and Legallois,(10)

(1) Weiss, loc. cit. — Sabatier, loc. cit.

(2) Sabatier, loc. cit.

(3) Haller, Elem. phys., vol. ii. p. 134.

(4) On suspended respiration from drowning, hanging , and suffocation, London, 1791.

(5) Loc. cit., p. 133.

(6) System of human anat., vol. i. p. 38.

(7) Hamberger, Physiologie , p. 708.

(8) Mem. de Paris, 1770, p. 245.

(9) Loc. cit.

(10) Did. des sc. méd. vol. v. p. 440.


ANGEIOLOGY.


197


as 6 : 5, Brown Langrish as 11 : 10.(1) Gordon lias found the two ventricles nearly equal in some cases, (2) and Portal asserts that their capacity is the same in young people. (3)

These differences in the estimates of authors furnish a new argument against the common opinion, since we should presume that they depend on greater or less accidental obstacles to the pulmonary circulation.

We cannot however deny but that the capacitj^ of the right portion of the heart is a little greater than that of the left, because the blood brought by the vena cava has received the fluid contained in the thoracic canal. It is also proved by the difference relative to the age in the degree of disproportion, this being, directly after birth, less than at a more advanced period of life. (4)

Legallois has also found the right portion of the heart a little broader than the left in every kind of death, both after strangulation and from the loss of blood.(5) The facts related prove only that the right portion of the heart can contract as much as, and even more than the left, in certain circumstances, and that the left is also susceptible of becoming larger than the light, but not that the capacity of the latter exceeds that of the former during life.

4th. The fibres of the right side, especially those of the ventricle, are not arranged in the same manner as those of the left side.

a. The thinness of the right ventricle is attended also with fewer fibrous layers, a fact already pointed out by Senac,(6) but which Wolff has indicated more precisely in saying that the right ventricle is formed of three layers only, while that of the left side presents six, counting the fleshy fasciculi of its internal face. (7) We have not however been able to find this number of laj'ers. Usually we have observed on each side only three distinct layers, two oblique, and one internal longitudinal.

b. The fibres of the right ventricle are flatter and thinner than those of the left. Thus the former form flattened fasciculi, and the second rounded and thicker fasciculi. The latter ramify more ; they are separated by fat, and have spaces between them, while we can hardly distinguish the former from each other except by the direction of their fibres.

e. The fibres of the right ventricle are more oblique and annular, while those of the left are more longitudinal.

d. The layers of the right ventricle, although thinner, are much more distinct than those of the left ventricle ; besides the latter are still

(1) De part.corp hum. fabric., vol. ii. p. 133.

(2) Loc. cit., p. 33.

(3) Doc. cit.

(4) Portal, loc. cit.

(5) TV. du cœur, vol. i. p. 200.

(6) De stratis ßbrarum cordis in Universum, in the Nov. act. Petrop. vol. iii. an 1785, p. 234-238.

(7) Loc. cit., p. 234.


198


DESCRIPTIVE ANATOMY.


more similar in regard to direction, which doubtless contributes to make the left ventricle firmer, bat proves at the same time that we should exercise some judgment in determining the number and direction of these layers. Such at least is the positive result of our researches. This also is the opinion of Wolff himself, who has studied the arrangement of the heart with too much exactness.

5th. The primitive form of the heart, that of a canal curved on itself, is more evident in the left ventricle than in the right.

6th. The nerves of the left side are larger and more numerous than those of the right side.


CHAPTER II.

SPECIAL REMARKS ON THE HEART.

§ 1304. We usually describe first the right half of the heart ; and in order to follow the direction of the circulation of the blood, we begin with the right auricle.

I. RIGHT AURICLE.

§ 1305. The right auricle ( atrium anterius , s. venarum car arum , s. der truin'), forms that portion of the base of the heart situated farthest on the right and forward.

Its form is almost square ; the vena cava superior descends obliquely from right to left, and from behind forward, towards its upper and right angle, and the vena cava inferior ascends in a contrary direction towards its lower and right angle. Notwithstanding this difference in the direction of the two venæ cavæ, we must admit that they unite and form a single trunk in the cavity of the auricle, for they unite on the right forward and backward, and the absence of the left side of their circumference is only apparent, since this side in fact exists, but is dilated to produce the muscular part of the auricle. The upper and left angle of the latter extends into a small blunt appendage, formed like a rounded square, which is observed before the lower paît of the aorta. The lower and left angle is rounded.

We observe transverse fibres on all the circumference of this auricle, directly below the inner membrane of the heart, which, becoming thinner and separating from each other above and below, are prolonged for a small distance around the superior and inferior venæ cavæ. They are thinner where they surround the point of union of the two venæ cavæ forward, and are extended more uniformly, and are smoother on the right side, both on thsir outer and on their inner face.

But the left part of the posterior face of the anterior and unattached wall of the right auricle, which is the most extensive, is uneven internally. This unevenness depends on much larger and transverse fasci

ANGEIOLOGY.


199


culi, which are united by other smaller oblique fasciculi, so as to present a reticulated appearance. These fasciculi, with which the transverse fibres of the auricle are united, appear between two longitudinal smooth bands which proceed only along its internal face. One of these tw'o bands, the left, descends a short distance from the anterior part of the venous orifice of the left ventricle ; the other, the right, situated almost in the centre of the anterior wall, a little however to the right, descends toward the left side, along the union of the two venæ cavæ. These fleshy fasciculi have been called the pectinÅ“al muscles (AT. pectinati ) .

The posterior wall of the right auricle forms the anterior face of the interventricular septum. We discover in it several remarkable parts, some of which belong to the history of the development of the heart.

On the right side and toward the centre is the fossa ovalis ( fossa ovalis , s. valvula foraminis ovalis, s. vestigium foraminis ovalis), an oblong and rounded depression, which varies much in size. This fossa is very distinct from the posterior wall of the auricle at its upper part, a little less so on its sides, especially on the right, and is generally blended with it below, particularly on the right side. The more extensive it is, the less evident are the limits which separate it from the other parts of the posterior wall. It however not unfrequently presents a similar arrangement even when it is very small.

Most generally it exactly fills the space between the edges of the projection which surrounds it, and it is very tense, but not unfrequently it is much larger, and forms a valve, the loose edge of which corresponds to the left auricle. We almost always observe a greater or less depression above, between its extremity and the upper part of the projection which surrounds it. Very often also we see in this place one or more openings by which the cavity of the two auricles communicate. This arrangement is not constant, and it is entirely independent of the extent either of the valve or of the depression, although it occurs particularly when the valve is very broad. Even when the openings are large and numerous, they seldom descend below the central part of the projection which surrounds the depression, so that the septum of the auricles is complete in regard to the separation of the blood contained in the two cavities.

This place, especially in its upper part, is the thinnest portion of the septum and of the auricle generally. W T e however always observe muscular fibres between the two layers of the internal membrane of the heart, that of the right and that of the left auricle.

The projection which surrounds this depression is formed of reticulated muscular fibres. It is called the ring or the isthmus of Vieussens ( annulus , s. isthmus Vieussenii). Its right portion separates the right and left halves of the septum. Although it does not project at its lower part, it is however complete in this place also.

We observe in its circumference several openings of the cardiac veins, called the foramina of Thebesius ( foramina Thebesii). At the


200


DESCRIPTIVE ANATOMY.


lower end of the inferior edge of the ring a circular fold of the inner membrane of the right auricle commences, this is called the Eustachian valve ) or the anterior valve of the foramen ovale ( valvula Eustachii , s. foraminis ovalis anterior). { 1) This fold extends more or less to the right, along the anterior part of the orifice of the vena cava ascendens into the right auricle, so that its lower edge is concave and attached while the upper is convex and loose within the right auricle. It imperfectly separates below the right and left halves of the right auricle.

This valve varies much in regard to size, form, and texture. It is usually more perfect and proportionally larger in the fetus than at any time after birth. In the adult it is often entirely changed, at least at its upper part, into a reticular tissue, and in many cases some filaments only trace the valve, and these frequently do not exist. It usually contains some muscular fibres, but it is often only a simple fold of the internal membrane.

An intimate relation generally exists between the Eustachian valve and the fossa ovalis, the former being more developed in proportion as the septum formed by the latter between the two auricles is less perfect, and vice versa ; but to this rule there are numerous exceptions.

The valve acts principally in the fetus. At this period of life it conducts the blood of the vena cava superior toward the opening of the septum or the foramen ovale. Hence the relation between it and the valve of this opening.

In the adult it may prevent to a slight degree the reflux of the blood from the vena cava superior, and from the right auricle generally into the vena cava inferior. Directly at the left side of the left branch of the isthmus of Vieussens, between this branch and the venous orifice of the right ventricle, there is a large and rounded opening, the orifiee of the large coronary vein of the heart ( orificium venae coronariÅ“ cordis magnÅ“).{ 2) This opening is sometimes divided more or less distinctly into several, and generally is more or less perfectly closed by a valvular fold, which arises at its lower part. This fold, called the valve of Thebesius ( valvula Thebesii), has its upper and .concave edge unattached, while its lower and convex edge adheres. Sometimes it does not exist in other cases it is replaced by one or more imperfect transverse bands ; finally, in some subjects there are several, even as many as six, situated one behind another.

(1) Winslow, Description d'une valvule singulière de la veine cave inferieure , à l'occasion de laquelle on propose un sentiment nouveau sur la fameuse question du, trou ovale , in the Mém. de Paris -, 1717, p. 272. Eclaircissement sur un Mèm.de 1-717, Ibid. 1725. — Haller, De valvulâ Euslacliii, Gottingen, 1737. — L. Crell, De valvulâ venœ cavœ Eustachianä, Wittenberg-, 1737.- — Brencle), De valvulâ Eustachianâ inter venam inferiorem dextramque cordis auriculam positâ, Wittenberg, 1738. — Haller, De valvulâ Eustachii prog.r. ii. Gottingen, 1748. — J. M. Diebolt, De foramine ovali, Strasburg, 1771. — J. F. Lobstein, De valvulâ Eustachii , Strasburg, 1771. — C. F. Wolff, De foramine ovali cjusque usu in dirigendo sanguinis motu observationes novœ, in the N. C. Pctrop, vol. xx. p. 357. — H. L. Leveling, De valvulâ Eustachii et foramine ovali, in the Obs. anal, rar f asc. i. 1786.

(2) Wolff, De orificio venÅ“ coronariÅ“ magnee ; in the Act. P elrop. 1777, p. 234-257.


ANCEIOLOGY.


201


II. RIGHT VENTRICLE.

§ 1306. The anterior , pulmonary, or right ventricle ( ventriculus anterior, s. dexter , s. pulmonalis ) is composed of an upper and lower portion, which are separated bj the upper part of the venous valve. The former unites directly to the right auricle, the latter to the pulmonary artery, and its walls are thinner than those of the former. It terminates in a conical extremity, which projects upward and backward above the left ventricle and the septum of the heart. The pulmonary artery arises from this part.

The internal or posterior wall is formed by the septum of the heart and is slightly convex ; the anterior is still more so. The posterior wall is smoother than the anterior at its upper portion and very often entirely so below the arterial opening. The net-woik formed by the projecting muscular fasciculi is much more complete toward its summit than toward its base.

The anterior wall of the pulmonary ventricle is thinnest above toward the septum and thickest below also near the septum. Its thickness when the heart is strong and not very much distended is more than two lines, but less than this in the latter point. The two parts are scarcely a line thick even in those hearts which are neither very much distended nor small.

The quantity of blood in the right ventricle after death varies from one ounce and a half to three ounces.

§ 1307. The venous valve of the right auricle arises from the circumference of its venous orifice. It is called the tricuspid valve ( val vida triglochis , tricuspis ), because, although it forms a single membrane, it is higher in three points than in the short spaces between them, and thus three slips are formed.

Of these, one, which is the largest, arises from the external and anterior part of the circumference of the venous orifice. The other two are smaller and arise from the inner and posterior part of this circumference, one over the other ; so that consequently there is an external and larger slip, and two internal, an upper and a lower slip.

The last two are separated from each other by a space not so deep as those between them and the external. It is then more correct to admit only two slips, an anterior and external and a posterior and internal.

The first is much higher than the second.

The tendinous filaments of the upper extremity of the anterior or external slip are attached to this upper part of the septum. They are few in number. We usually find in the space only one or at most two short muscles, to which are attached those filaments farthest to the left ; the others are inserted in its smooth wall. Most of those filaments which come from the central and lower parts of the edge of


VOL. II.


26


202


DESCRIPTIVE ANATOMY.


this slip are attached to the summits of five or six of the fleshy pillars coming from the middle and lower parts of the anterior wall.

The filaments which arise from the posterior slips are mostly attached to the smooth folds of the septum, except a few, which are inserted in two or three small fleshy pillars, all of which except the lowest come from the septum.

The arterial orifice generally extends about three fourths of an inch higher than the venous. The sigmoid valves are thin. Their tubercles ( noduli Morgagnii ) are slight swellings, which however are often well marked in the young fetus.

III. LEFT AURICLE.

§ 1308 . The left, posterior, or pulmonary auricle (atrium sinistrum , s. posterius, s. venarum puhnonalium, s. aorticum) is of an oblong square form, considerably more broad than high.

It is separated below and posteriorly from the left ventricle by a circular groove, upward and to the right from the right ventricle by a similar depression. The pulmonary artery, the aorta, and the vena cava superior are also found upward and outward, between it and the right ventricle ; so that the external part of its right and left extremities is alone visible.

Its upper left angle rises into an auricular appendage ( auricula sinis tra ), which goes forward to the left and upward, directly behind the pulmonary artery, separating very much from the rest of the auricle. This appendage, which is narrower, longer, and on the whole larger than that of the right auricle, is circumscribed by rougher edges. It curves three or four times and finally terminates in a sharp summit, below and before the pulmonary artery.

The posterior wall of the lower part, the sinus of the auricle (sinus venarum puhnonalium), receives where it is continuous with the lateral parietes the four pulmonary veins, two on each side, the upper being larger than the lower. One of the two veins of the same side opens directly above the other, while between those of the two opposite sides is the whole breadth of the auricle ; so that the two pairs occupy the whole height of the posterior wall.

The parietes of the whole auricle are muscular and formed principally of transverse fibres. They are smooth with the exception of the appendage. We observe in its whole length an anterior and a posterior series of very prominent transverse fasciculi, united by other smaller and oblique fasciculi, which proceed between two longitudinal bands, situated one on the right the other on the left.

The anterior wall is formed by the septum of the auricles and is also, like the posterior face of the septum, irregular in another respect. In fact we there observe a constant semicircular valve, which is however more or less developed. This valve leaves the upper edge of the transparent point which corresponds to the fossa ovalis of the right auricle (§ 1305 ). It is turned upward and toward the left. Its lower edge


ANGEIOLOGY.


203


is convex and attached, and its upper edge is loose in a greater or less extent. Sometimes there is only a slight projection in its place.

This valve extends behind the interauricular septum. Its lower edge is attached to the posterior face of the centre of the isthmus of Vieussens, and the space between it and this isthmus forms a small cavity ( sinus septi ), which terminates below in a cul-de-sac. This is only the upper part of the valve of the foramen ovale (§ 1305), which in the normal state always ascends on the posterior face of the isthmus. Of this we are readily convinced when it does not adhere to the isthmus in the centre ; for then the continuity is totally uninterrupted.

IV. LEFT VENTRICLE.

§ 1309. The left ventricle (venir i cuius sinister ) posterior, s. aorticus ) is the strongest of all parts of the heart and forms its figure. Its posterior wall and its anterior wall which forms the posterior face of the septum, are convex externally and concave internally : so that its whole form is oval. The internal face of the posterior wall is very much reticulated ; the anterior wall is smooth at its upper part and reticulated in the lower, but less so than the posterior wall. The fleshy pillars are rounded.

The thickness of the parietes is less toward the summit and greater at the base than in all other parts. In the adult it is five or six lines thick at the base and only three at the summit.

The capacity of the left ventricle varies in the adult from eight to twenty drachms.

§ 1310. Before the round venous orifice we find the mitral valve ( valvula mitralis), composed of an upper and a lower slip. The upper arises directly below or rather before the ring of the sigmoid valve of the aorta, and is attached by slips to three or four fleshy pillars, which all come from the internal face of the posterior wall of the ventricle, some above, others below, and among which we distinguish two particularly, an upper and a lower, which are much larger than the others. The inferior and external slip, which is much narrower, is attached by tendinous filaments to a short but very thick fleshy pillar.

All these fleshy pillars arise from the posterior wall of the left ventricle ; so that those of the upper slip arise near the summit of the heart, and cover those of the lower, so that we cannot perceive the lower slip until we have removed the upper or have detached it from its fleshy pillars.

The orifice of the artery is situated directly over that of the vein. Its sigmoid valves are thick and are generally supplied with tubercles ( noduli Arantii ), which are very distinct.


204


DESCRIPTIVE ANATOMY.


V. SEPTUM.

§ 1311,. In the normal state the septum of the heart completely separates its two halves, even when the valve of the foramen ovale is not united with the isthmus of Yieussens at its upper part. In the venous portion of the heart it is much thinner than the auricles, which it separates, and is much lower, as they project above it. It is not muscular in every part, and generally there are no muscular fibres in the upper part, of the old valve of the foramen ovale.

In the arterial portion, on the contrary, the septum is very muscular and is formed almost entirely by the fibres of the left ventricle. It projects considerably into the right ventricle, while in its posterior face, which forms the anterior wall of the left ventricle, there is a deep depression. Its height equals that of the ventricles. It is triangular and terminates in a point toward the summit of the heart. It is generally from four to five lines thick, and even more than a half an inch thick in those parts where the large fascicidi project above the surface in those subjects which have large hearts. It is thickest below the orifices of the large arterial trunks, and thinnest beyond this point toward the interauricular septum. It is almost always weaker at the summit, where the layers which constitute it are less compact and more easily separated from each other,


CHAPTER III

OF THE PERICARDIUM.

§ 1312. The pericardium (pericardium) (§ 1 293) ( 1 ) is a fibro-serous membrane (§ 354), which entirely envelops the heart and the origin of the large vessels, and unites them with the adjacent parts.

The fibres which strengthen its outer layer and which are very apparent in old men, arise from the central aponeurosis of the diaphragm and extend longitudinally over the serous membrane. They are very much developed, particularly forward and upward.

Its lower face, w’hich corresponds to the lower and flat face of the heart, is intimately united to the upper face of the central aponeurosis of the diaphragm by a very short cellular tissue.

It is covered on the sides and forward by the inner walls of the pleuræ.

Behind, it is attached to the esophagus and to the root of the right lung.

(1) J. M. Hoffmann, Diss. de pericardio, Altdorf, 1690. — A. B. Heimann, De pericardio sano et morboso, Leyden, 1729. — Lanzoni, De pericardio ; in Opp. omn., Lausanne, 1738.


ANGEIOLOGY.


205


§ 1313. The pericardium incloses not merely the heart but also the origins of the large vessels, whence it is reflected on itself in every direction to arrive at the centre of the heart.

When examined from before backward and from above downward, we notice the following arrangement :

It envelops the aorta and the trunk of the pulmonary artery forward for about two and a half inches, unites these two vessels very closely, and passes uninterruptedly from one to the other ; so that the corresponding parts of their circumference are retained by a cellular tissue.

The posterior part of these vessels is not covered in the same extent by the pericardium.

From the aorta this membrane passes to the right on the vena cava superior, to about an inch above its entrance into the right auricle, descends obliquely from left to right on its anterior portion, then arrives at the right pulmonary veins, on which it descends to about half an inch from their entrance into the left auricle, then goes on the anterior part of the vena cava inferior, directly below its opening into the right auricle, and wholly surrounds it except a small part of its posterior portion. Thence it goes to the left, on all the surface of the left pulmonary veins, and finally covers the left branch of the pulmonary artery below.

From all these parts the pericardium is reflected on itself. It adheres feebly to the large vessels, but much more strongly to the auricles and ventricles.

As in all other serous membranes, the inner and reflected portion of the pericardium is thinner than the external. It closely envelops thesurface of the parts inclosed by the membranous sac, and, except in those parts where it is reflected, it is entirely separated from the outer layer, although they touch ; so that the circumference of the heart is perfectly loose and is attached only by its upper part.

CHAPTER IV.

OF THE DIFFERENCES OF THE HEART WHICH DEPEND ON THE DEVELOPMENT AND ON THE SEX.

§ 1314, The differences presented by the heart in regard to its development are considerable.(l) They relate to its volume , situation , form , and texture.

1st. Volume. The heart is much larger in proportion to the body in the early periods of life than at a more advanced period. The relation

(1) The principal works on this subject are mentioned in Danz, Grundriss der Zergliederungskunde des ungebornen Kindes in den verschiedenen Zeilen der Schwangerschaft, vol. ii. Giessen, 1793, p. 185-188. — See also Meckel, Mémoire sur le développement du cÅ“ur ; in the Journal complémentaire , vol. i. p. 259. — Rolando, Memoire sur la formation du cÅ“ur ; same journal, vol. xv. p. 323, vol. xvi. p. 34.


208


DESCRIPTIVE ANATOMY.


between it and the body is as 1 : 120 in the full grown fetus and in the early years of life, while before this period, in the second and third month of pregnancy, it is as 1 : 50.

2d. Situation. At first the heart is not oblique, but its summit looks directly forward and a little downward. It is only at the fourth month that it begins to turn slightly toward the left side.

3d. Form. The differences in its form are the most important and relate both to the circumference of the whole organ and to the mode of limiting its cavities. Observers have not decided whether there is or is not in the human fetus a period very near its origin, when the heart forms only a single cavity, composed of several compartments placed near each other. But if this period exists, it passes rapidly, since all the external parts are developed in the fetus at the end of one month.

A. OUTER CIRCUMFERENCE.

a. At first the arterial portion of the heart is much smaller in proportion to the venous. The right auricle especially remains for a long time the largest portion of this organ. The permanent relation however begins to establish itself during the last half of uterine existence.

b. The arterial portion is at first flat and rounded : soon however its breadth exceeds its length. Its summit is at first single and blunt ; but as it enlarges it bifurcates. This phenomenon depends on the fact that the right ventricle from its situation does not at first concur to form the summit of the heart ; but it gradually extends downward and remains separated from the left ventricle by a considerable depression. This groove sometimes continues during life, but almost always disappears after the middle of uterine existence.

c. The right ventricle is at first much smaller than the left : they are soon equal in size : for a certain time the right ventricle is even a little larger, but it becomes smaller during most of uterine existence ; so that it is narrower in the full grown fetus and in the young child. The greater size of the right ventricle seems to result from the obstacles which often disturb the pulmonary circulation at an advanced period of life.(l)


(1) This at least has been observed by Portal ( Sur la capacité des ventricules du cÅ“ur ; in the Mem. de. Paris, 1770, p. 244-246). In the heart of a full grown fetus the left ventricle contained seven drachms of water, while the right contained only six and a half. The capacity of the two ventricles was the same in that of a young child ; in that of an adult the right ventricle contained eighteen drachms of water, and the left only seventeen. The experiments of Legallois (Diet, des sc. méd., vol. v. p. 440,) prove that we can introduce


In an adult, In a child,


grs. of mercury

5 Into the right ventricle, 1172 ( Into the left ventricle 1068

f Into the right ventricle, 828 ! Into the left, not softened I by pressure, - - 658

1 Into the left, softened, 822


ANGEIOLOGY.


207


d. In the early periods of life the upper and pyramidal extremity of the upper part of the pulmonary ventricle is less distinct from the rest of the organ than at more advanced periods : it elevates itself also less above the left ventricle and the septum. This peculiarity is very curious, as precisely the contrary is seen in many mammalia, especially the ruminantia and the hog.


B. INTERNAL ARRANGEMENT OF THE HEART.


The principal difference presented by the heart in this respect is, that its septum is imperfect in the early periods of life, whence its right and left portions then communicate with each other.

a. The interauricular septum is perforated during all fetal existence by an opening called the foramen ovale. This foramen is much greater as the fetus is younger ; so that we may consider the septum as primitively deficient and the two auricles then form a single cavity. The foramen ovale gradually grows smaller and occupies the lower and central part of the septum. The Eustachian valve is found very early directly before it and on the right, so as to occupy all its height. Hence as it arises from the anterior part of the circumference of the vena cava inferior, it separates the right and left auricle in such a manner, that this vein empties directly into the left auricle only. On the contrary, there is no trace of the closing of the foramen ovale on the left side till the commencement of the third month. But about this period this foramen begins to be obliterated by the formation of its valve, which arises from the posterior part of the vena cava.


In a still-born child, In a seven months’ fetus,

In another about the same age,


grs. of mercury

( Into the right ventricle, 34 ! Into the left ventricle,

I not softened, - - 37

^ Into the left, softened, - 78


Into the right ventricle, 23

Into the left, not softened nor flaccid, - - 34

Into the right ventricle, 21

Into the left, softened, 54


In repeating these experiments, also with mercury, we have obtained the following results :


In a man 50 years old, In a woman 46 years old,

In a woman 40 years old,

In a man 34 years old, “ 30 “ “ 26 “ - In a boy 16 “ - In a girl 7 months old, In a new born boy which had breathed, In a still-born boy,


R. ventricle

L. ventricle

L. auricle

R auricle

oz. drs.

oz. drs.

oz. drs.

oz. drs.

30

10

25

20

40

22 4

22

15

55

40

41

35

32

15 4

21

25

32 4

28 4

25

22 4

28

20 4

20

18

41 4

21 4

37

29

2 4

1 4

1 4

1 6

1 6

2

1 6

1 2

1 4

2

together 4 ounces.


208


DESCRIPTIVE ANATOMY.


As this enlarges, the Eustachian valve diminishes and recedes from the septum, while on the contrary that of the foramen ovale approaches it. The latter also becomes narrower and more tense, especially in the latter months of pregnancy ; so that it closes the opening more exactly. The termination of the vena cava inferior in the heart suddenly changes, and this vessel empties itself no longer into the left auricle but into the right. This change is also favored by that which takes place in the situation of the heart, which varies so that its summit corresponds to the left ; the right auricle is more than usually elevated above the vena cava inferior, at the same time that the Eustachian valve is removed from the septum and is carried forward.

The valve of the foramen ovale increases from below upward along the lateral edges of this foramen. At the sixth month of pregnancy it has already arrived at its upper part ; it then passes beyond it ; so that â– the interauricular septum is entirely filled, except a small space, which is no longer an opening but a very short canal, formed forward by the upper part of the ring of the foramen ovale and backward by the upper part of the valve.

b. It is not yet well demonstrated whether the ventricles, like the auricles, form at first only a single cavity without a septum, although the development of the heart in the animal series, and the deviations of formation of this organ lead us to this opinion. We have always found a trace of the interauricular septum at the summit of the heart, even in the youngest fetuses we could examine. During the first two months however, or at least till the middle of the second, this septum presents at its upper part a foramen, at first rather large, but it gradually diminishes, and is found below the origin of the large vessels, so that the two ventricles form only one, which is imperfectly divided into two portions. This opening is obliterated at the period when the artery which arises from the ventricles becomes double, instead of single, as it was at first ; that is, when the pulmonary artery, which before was blended with the aorta, becomes a proper and distinct vessel. Its obliteration then much precedes that of the foramen ovale.

4th. Texture. The thickness of the parietes is much greater compared to the size of the cavities during the early periods of life than subsequently, and the greatest size of the heart then depends on this cause.(l)

The parietes on both sides are then equally thick. The difference which always exists afterwards, and which is scarcely perceptible even in a full grown fetus, does not begin to be developed till the second half of uterine existence.

The fibrous texture and the different layers of fibres are always more apparent at the early periods of life than at a more advanced age.

(1) Gordon is mistaken in saying- that the parietes of the heart are proportionally thinner in the early periods of life than at a more remote period ( System of human anatomy , vol. i. p. 53.)


ANGEJOLOGV.


209


5th. Color. The color of the heart is much blighter when the subject is younger.

No fat has as yet accumulated on the surface of this organ in the early periods of fetal existence ; but this is generally the case with all parts of the body.

The pericardium is then proportionally thicker than at subsequent periods, and its internal or reflected layer adheres less intimately to the heart.

C. SEXUAL DIFFERENCES,

§ 1315. The only sexual difference seen in the heart is that it is proportionally a little larger in males.


CHAPTER V.

MOTIONS OF THE HEART,

§ 1316. The circumstances in the history of the motions of the heart, or in the heart in its active state, which deserve examination, are,

1st. The changes in its form.

2d. The succession and simultaneousness of the motions in its different parts.

3d. The relation between the cavities of the heart in its different states and the blood.

4th. The number of its motions.

5th. The changes in its situation.

6th. The duration of its motions.

7th. The conditions on which they depend.

§ 1317. 1st. The heart diminishes in contraction and enlarges in dilatation in every directional )

2d. The auricles and ventricles contract and dilate alternately, so that the two auricles and the two ventricles execute the same motions at the same time. (2) The auricles in contracting send the blood into

(1) Sur le changement du figure de cœur dans le style , in the Mêm. de Paris, 1731, hist. p. 33, 40.

(2) The motions of the heart have been carefully analyzed by Laennec with the aid of the stethoscope, by which we can study them more correctly than by opening and inspecting living animals {De l'auscultation médiate, vol. ii. p. 195-227). From this analysis are deduced numerous important practical facts.

In the motions of the heart we must consider their extent, its impulse, the nature, and intensity of the sound and the rythm, according to which the different parts of the organ contract.

1st. Extent. In a healthy and moderately fleshy subject, the pulsations of the heart are heard only in the space between the cartilages of the fifth and sixth true ribs, and under the lower part of the sternum. Those of the left cavities correspond principally to the first point, and those of the right to the second. If the sternum is short, we hear the pulsations in the epigastrium also. When the subject is so fat that

Vol. IT. 27


210


DESCRIPTIVE ANATOMY.


the ventricles, which then contract on it, and throw it into the arteries at their base. A small quantity of the fluid however always returns Irom the arteries into the ventricles, from these into the auricles, and thence into the veins which open into them.

3d. The cavities of the heart are almost entirely empty when they contract. However a little blood always remains, which is attached especially to the reticulated surface of their inner face.

4th. When the ventricles contract the apex of the heart beats against the anterior wall of the chest, notwithstanding that the organ shortens. This arises principally because that the auricles are then filled, both by the blood disgorged by the veins and by that which

they cannot be felt by the hand, the space in which they can be heard by the stethoscope' is sometimes only about a square inch. In thin persons, when the chest is narrow, and even in children, they always have more extent. They may be heard in the lower third, or even in the three lower fourths, of the sternum; sometimes also, under all this bone, at the left anterior and upper part of the chest to near the clavicle, and sometimes, but less manifestly, under the right clavicle. The subject rarely enjoys perfect health when the extent of the pulsations exceeds these limits, so that they are hoard in the left side of the chest, from the axilla to the region corresponding to the stomach ; and to a similar extent on the right side, at the left posterior part of the chest ; finally, on the right posterior part, a successive progress, which would seem to be constant, and which is attended with a progressive diminution in the intensity of the sound. In this respect w r c may state as a principle, that the extent of the heart’s pulsations is directly as the feebleness and the thinness of its parietes, especially those of the auricles, and inversely as their force and thickness.

_ 2d. Impulse of the heart. In contracting, the heart gives a sensation of percussion, raising or repelling the hand, or any other part placed upon the anterior walls of the thorax. In some individuals this impulse is visible, and sometimes causes a very extensive motion, which raises the parietes of the chest, the epigastric region, and even the clothing. It is however but slightly marked when the proportions of the heart are normal, and is often imperceptible in fat people. It is perceptible only during the systole of the ventricles. If the contraction of the auricles sometimes produces a similar phenomenon, it may be distinguished from the first, inasmuch as most generally it consists only in a kind of rumbling, which is heard very deeply in the mediastium. This impulse is generally perceptible only between the cartilages of the fifth and sixth true ribs, or, at most, in the lower half of the sternum, and in some subjects, when the sternum is very short, in the epigastrium. Generally speaking, it is inversely as the extent of the pulsations, and directly, as the thickness of the ventricles.

3d. Nature of the sound. On listening attentively we distinguish during the pulsations of the heart two distinct sounds : one, duller and continued ; the other, quicker, and more distinct. The first is simultaneous with the pulsations of the arteries and marks the contraction of the ventricles; the second is caused by the contractions of the auricles. That heard at the lower part of the sternum belongs to the right cavities; that distinguished between the cartilages of;the fifth and sixth ribs depends on the left cavities. In the normal state, this noise is similar and equal on both sides; and is no where so loud as in the precordial region. It is as much stronger as the parietes of the ventricles are thinner, and as the power of impulse of the heart is less.

4th. Rythm. The duration of the sound caused by the auricles is shorter than of that produced by the ventricles ; hence, the contractions of the auricles do not continue as long as those of the ventricles. There is a well marked but short interval of rest between these two sounds. This observation proves that the heart, like all other muscles, is alternately in a state of action and of rest. We may admit, that of the twenty-four hours, the ventricles have twelve and the auricles eighteen hours of rest ; i n supposing also that the cavities of the heart arc entirely passive in their dilatation. In fact, Laennec admits that in the most general state of the whole duration of time in which the successive contractions of different parts of the heart, occur, a third at most, or even a quarter, is occupied by the systole of the auricles ; a fourth, or a little less, by absolute rest, and a little more than a half by the systole of the ventricles. F. T.


ANGEIOLOGY.


211


flows back from the ventricles, so that the latter are pushed forward : but it depends also a little on the extension of the arterial trunks at the moment when the arterial blood which is sent from the ventricles passes through them.(l) From not attending to these last two circumstances it was for a long time impossible to explain the pulsations of the heart during* its contractions, except by admitting that it lengthened in performing this motion, which is very improbable.

5th. The mean number of pulsations of the heart in the adult is seventy per minute. But it varies much according to the individual. The pulsations are generally more feeble and fewer in the female. If we except the early periods of life when the contractions of the heart are few, the number of its pulsations is much greater the nearer it is to the period of its formation.

6th. We generally consider the heart as that part in which irritatability continues the longest. But it follows from the observations of Haller, Zimmerman, and Oeder, that there are exceptions to this law ; and the observations of Fontana, Crève, (2) and Nysten,(3) with which our own agree, demonstrate that this is not true, at least to the arterial portion, since the ventricles lose their irritability before the other muscular parts of the body ; but the auricles preserve it the longest, (4) and that the right auricle remains irritable longer than the left. Haller has attempted to prove that this latter difference depends on the circumstance that the right auricle is stimulated longer by the blood within it, (5) but we have often seen it in hearts which were removed from the chest and totally destitute of blood. Nysten Iras observed it also in persons who were beheaded. We then have reason to say it depends on the greater tenacity of life in this part of the heart, and the more as the tenacity increases in animals in a direct ratio with the predominance of the venous system in them,

7th. The conditions of the action of the heart are the same as those of muscular action generally. For this then we refer to the details already mentioned in the first volume.

(1) When the ventricles contract, the point of the heart strikes the left lateral wall

of the chest, between the cartilages of the fifth and sixth ribs. The two causes mentioned by the author, the filling of the auricles and the extension of the trunks of the arteries, doubtless contribute to produce this phenomenon; but we may admit also that while the ventricles contract, their moveable point rises, and performs the motion of a pendulum on the base of the heart, which, being more fixed, serves as a point of support. F. T.

(2) Vom Metallreize , Leipsic, 1796, p. 100.

(3) Recherches dephysiol, et de chimie , Paris, 1811, p. 307.

(4) As Davy observed in experiments for another purpose. See his Researches on nitrous oxide, London, 1800, p. 352.

(5) De cordis m,otu a stimido i\ato, in the Comm. Gott., vol. i,


2 12


DESCRIPTIVE ANATOM V


CHAPTER VI.

OP THE HEART IN THE ABNORMAL STATE.

§ 1318. The anomalies of the heart are divided into two sections, according as they affect the form or the texture of this organ. We shall mention here only the first, having spoken of the latter in the first volume, when treating of the alterations in the texture of the vessels, of the muscles, and of the serous membranes.

§ 1319. The deviations in the formation of the heart embrace anomalies which may exist in number, situation, volume, and figure.

§ 1320. In regard to number, the heart may vary from the normal state in two opposite modes, that is, may be either wholly or partially deficient, or may have supernumerary parts.

The heart is entirely absent only when the upper half of the body is very imperfectly developed, and the head is then usually deficient. However, this rule presents but rarely exceptions of two kinds : for, first, the heart sometimes appears when the head does not exist ;(1) and secondly, this organ is sometimes wholly(2) or partly deficient(3) in monsters where the trunk and head are not very much deformed. We shall speak of the partial absence of the heart hereafter.

The plurality of the heart, the body being simple, is infinitely more rare, however common it may be when the body is double, but is not seen constantly even in the latter case. We know of but one instance of a perfect plurality of the heart where the body was single. We are led to this anomaly by the fissure of the ventricles and by the congenital existence of abnormal and hollow appendages to the heart. (4)

§ 1321. The anomalies in the situation of the heart are congenital or accidental. In the first case the organ exists sometimes within, and sometimes outside of the cavity of the thorax.

When found in the chest it may be,

1st. Straight, and then either perpendicular, or horizontal, or finally placed so that its summit looks upward.(5)

2d. Reversed, having its base to the left and its summit to the right, an anomaly which exists singly or which is attended with the more or less perfect inversion of the other organs. (6)

(1) We have collected all the instances of this anomaly in our Handbuch der pathologischen Anatomie, vol. i. p. 165.

(2) See our Handbuch der path. Anat,, vol. i. p. 414. Besides the cases there mentioned, two have been published since; one by Brodie {Phil. Trans. 1811), and the other by Lawrence {Méd. Chir. Trans.), vol. v.

(3) Rœderer, in the Comment. Gott., vol. iv. — Meckel, Handb. der path. Anat., vol. i. p. 421.

(4) We have collected all the cases of this anomaly in Meckel, De duplic. monstrosa, p. 53, and Handb. der path. Anat., vol. ii. p. 33-45.

(5) Meckel, Handb. der path. Anat; vol. i. p. 418. — Bertin in his work has figured a heart which was situated transversely in the cavity of the thorax.

(6) One case of this kind now before us has been figured in Meckel, De conditionibus cordis abnorm ., Halle, 1802, vol. i.


ANGEIOLOGV.


213


3d . Deeper than usual. ( 1 )

When it exists out of the chest two cases are possible.

1st. The anomaly being slight the heart hangs loosely outward, either in its usual place(2) or higher than it is generally, in the cervical iegion.(3) In this case the pericardium is usually but not always deficient. On the other hand it sometimes but very rarely happens that this membrane is not found even when the heart is situated in the chest, and then it is replaced by the pleura. (4)

2d. The anomaly existing in a greater degree which is also still more rare, the heart is found in the abdomen, (5) a deviation of formation to which the very sloping situation of this organ in the pectoral cavity leads.

The accidental anomalies in the situation of the heart depend on the accumulation of solids or liquids within the chest or the penetration of foreign bodies there, and follow no constant and fixed laws.

§ 1322. Anomalies in the volume of the heart are congenital much less frequently than accidental. They however sometimes have the character of a primitive formation, and are even hereditary in many families. The heart is then too small or too large. We often find both of these anomalies in the different parts of the same heart.

The smallness of the heart(6) is much more rare than its excess in volume. It is often carried to an extreme point although the formation of the organ is unchanged. (7)

As to the excessive size of the heart, we must distinguish the pure and simple increase in its mass, the thickening of its parietes,(8) from the thickening of its parietes with an increase in its capacity, (9) and from its simple dilatation or an increase in its capacity(lO) with or without a thinness of its parietes, since we find all these states sometimes insu (1) Meckel, Handb. der path. Anat., vol. i. p. 417.

(2) Id. Ibid. vol. i. p. 406.

(3) Id. Ibid. vol. i. p. 98, 99.

(4) See our Handb. der path. Anat., vol. i. p. 110.

(5) Deschamps has mentioned an instance of this in Sedillot, Recueil périodique, vol. xxvi. p. 275-279.

(6) We have mentioned several cases in our Handb. der path. Anatomie, vol. i. p. 470-472.

(7) Consult also, on the wasting of the heart, Laennec (De l’ausc. Med. vol. ii. p.

291), and Bertin (Des mal. du cÅ“ur, p. 387). The latter admits two kinds ; one where the walls of the heart are collapsed, the other where the same parietes, especially those of the ventricles, are, on the contrary, dilated, and at the same time become thinner ; this is the state termed passive aneurism. F. T.

(8) Different instances of the simple increase of the mass of the heart have been reported by Vetter, Aphorismen aus der pathologischen Anatomie, p. 99. — Legallois, in the Bullet, de l'Ec. de Med., 1813, 1814, p. 69. — Morgagni, Ep. anat. med., 30 to 20. — Burns.

(9) We find several cases of it in Morgagni, Epist. anat. 18 to 28, and 30. — Corvisart, Malad, du cœur. p. 61.

(10) Many instances of this anomaly are mentioned in Burns. — Morgagni, Epist. anat., 18 to 2, and 14. — Dundas, On a peculiar disease of the heart, in the Med. sure . Trans., v©l. i. p. 37.


214


DESCRIPTIVE ANATOMY.


luted and sometimes united.(l) The last two are termed aneurisms of the heart, which in the first case is called active, and passive in the second. The active aneurism is more common on the left side and the passive on the right. These two states usually coexist, the left side being dilated actively, and the right side passively, to a greater or less degree. (2) Sometimes the parietes of the left side have only become thicker, and those of the right side are on the contrary thinner, with or without dilatation at the same time. (3) However it often happens that one part or the other is diseased, each in its

(1) This distinction neglected by Corvisart who understands by the terms active aneurism and passive aneurism only a dilation of the heart with a thickening or thinness of its parietes, was made by Bertin in 1811, in a memoir presented to the Institute. Bertin admits three distinct forms of hypertrophy of the heart, that is, of its total or partial fleshy thickening : 1st, simple hypertrophy, in which the cavities of the organ preserve their natural capacity, at the same time that the parietes are more or less thickened : 2d. aneurismal hypertrophy , in which the cavities are dilated and the parietes are thickened ; this is the active aneurism of Corvisart : 3d, concentric hypertrophy, in which the thickening of the parietes is attended with a greater or less contraction of the cavities. He also distinguishes two binds of aneurismal hypertrophy ; one in which the parietes are thickened, and the other where the parietes preserve their natural thickness, so that the increase takes place in some measure according to the extent and the circumference, or according to the surface. He has also remarked, that in the hypertrophy of the ventricles the thickness often diminishes from the base to the point, but it is sometimes about the same at the point as at the base, and in some cases is more marked in its centre, and diminishes toward the point and even toward the base. It may be equal to fifteen lines, and more, although Laennec asserts that it never exceeds four or five lines. Sometimes we find in the same ventricles one portion which is dilated and thickened, and another contracted and thickened, or one part thin, while tbe other is thick. We sometimes observe a great difference between the parietes of the ventricles, especially on the right side, and the fleshy pillars, the latter being doubled or tripled in extent, while the parietes are not, or but very slightly, thickened. In other cases, the hypertrophy of the left ventricle seems to take place at the expense of the pillars, which are effaced or are hardly visible. The hypertrophy of the left ventricle is generally attended with that of the septum. We sometimes observe also a hypertrophy of the interventricular septum only. The fleshy pillars of the right ventricle have been found so thickened and intercrossed that there was hardly any cavity. Hypertrophy also often affects both ventricles at once, but not unfrequently they present an opposite state. The point of the thickened ventricle always descends lower than that of the other. The three forms of hypertrophy are observed in the auricles, but the aneurismal is the most common. The thickening is nearly equal in all the extent of the pariete3, especially in the left auricle. The muscular fasciculi of the right auricle sometimes increase in volume. Finally, in certain cases, the parietes of this auricle are so much thickened in all their parts, that they imitate those of the corresponding ventricle. Again, whatever may be the form of the hypertrophy, Bertin admits, as its immediate and proximate cause, an irritation applied to the heart, which increases the activity of the phenomena of nutrition in this organ (Des maladies du cÅ“ur, p. 282). He admits also three kinds of dilatation of the heart, or to proper aneurism : 1st, dilatation, with thickening of the parietes, or aneurismal hypertrophy ; 2d, dilatation, with thinness of the parietes ; the passive aneurism of Corvisart, which is more rare than the preceding ; 3d, dilatation of the cavities, they being of their usual thickness, or simple dilatation, which has not hitherto been regarded. To these three classes he adds a fourth, which is doubtful ; the mixed dilatation, in which the parietes of the dilated cavity are thicker in some parts and thinner in others, and of their natural thickness in the rest. (Ibid, p. 368.) Consult also, on hypertrophy of the heart, Lallemand, Observations pour servir à l’histoire des hyper sarcoses du cÅ“ur, in the Archiv, gen. de méd. vol. v. p. 520. F. T 23.— Testa. Mal. del cuore, iii. c. xv.


AXGEIOLOGI .


215


usual manner.(l) The disease does not necessarily effect an entire half. Generally, passive aneurism exists only in the right auricle, and active aneurism only hr the left ventricle, whether these two states exist alone, or whether they are both found in the same heart. Sometimes however, but rarely, the right side is entirely or partially thicker than usual, or at the same time dilated ; and then sometimes the left side is also affected and sometimes it is not : sometimes also it presents a passive aneurism, or at least its walls have become thinner. Perhaps the passive aneurism is still more rarely confined to the left ventricle, while all the other parts of the heart are in the normal state. (2)

These affections are confined to one part of the heart only, much more generally than they are extended to the whole of it. Nevertheless, if we except the active aneurism of the left side, combined with the passive aneurism of the right side, which is frequently observed, we sometimes find hearts which are affected equally in every part. (3)

The diseased cavity of the heart is most generally dilated in its whole extent. A partial dilatation in the form of a cul-de-sac rarely exists.

The substance of the heart is sometimes, but very rarely, thicker in some parts from round excrescences which project on its internal face. We know of but one instance of this arrangement, and the specimen is in our cabinet. This is still more curious, as it throws much light on the formation of the polypi of the heart, which are explained with difficulty unless we admit that one or more of these excrescences are detached from then place of origin.(4)

§ 1323. The anomalies in the form of the heart relate either to its external or to its internal arrangement, or finally to both.

They are congenital much offener than accidental.

§ 1324. The congenital anomalies in the external form are,

(1) We find instances of the active aneurism of the left ventricle in Lancisi, De rep. mort., p. 137. — Lafaye, in the Mém. de Paris, hist., p. 29.— Corvisart, Journ. de méd. vol. xi. p. 257.— We find cases of the passive aneurism of the right ventricle only in Fleury, Bull, de l'Ec. de méd., 1807, p. 124. — Morgagni, Epist. anat., m. 18 to 6.

(2) We find one case in Corvisart, p. 99.

(3) Different cases which prove this proposition, both in respect to the simple thickening of the parietes, and also to passive aneurism, are mentioned in Vetter, loc. cit., p. 99. — Burns. — Morgagni, Ep. anat., m. 18 to 2, 23, 30, ep. 53 to 9. — Corvisart, p. 61, 87. — Testa, loc. cit., vol. iii. ch. xvi. a. 7, 8, p. 361-367.

(4) Laennec relates several cases of this abnormal arrangement ( De l auscultation mediate, vol. ii. p. 344) which he terms globular excrescences of the heart, and which he compares to the excrescences of the valves. Meckel’s mode of explaining them cannot be maintained. Bertin (loc. cit., p. 444) not only admits with Corvisart, Testa, Burns, Creysig, and Laennec, that polypi, or rather fibrinous concretions, may form, during life, in the heart, as in all other portions of the sanguineous system'; but he also adopts Kreysig’s theory, and regards them as resultingfrom an effusion, which occurs after inflammation of the inner membrane of the heart. These concretions are most generally free from all adhesions, at least organic ; but sometimes also they are perfectly organized, and have numerous vessels injected in bright red or black. This important fact, of which Bouillaud has published two remarkable instances ( Obs. et cons. nouv. sur Voblitér des veines, in the Arch. gén. de méd., voi. v.


216


DESCRIPTIVE ANATOMY.


1st. The form of the heart is more rounded ; this is sometimes met with alone, but is usually attended with several other anomalies already mentioned, or which remain to be described, as prolapsus, perpendicularposition, &c.

2d. The deep fissure of the summit of the heart, to which our remarks on the preceding anomaly apply.

The accidental anomalies in the external formation are principally the solutions of continuity , which must not be confounded with those which are congenital, for the latter implicate the inner form, and they consist essentially in anomalies of the connection of the two portions of the heart.

Solutions in continuity of the heart are fissures or wounds.

Fissur es(l) occur most generally after those pathological changes which supervene in the substance of the heart itself, or in the arterial trunks. They less commonly depend on external injuries, which do not directly affect the substance of the heart, but act either on the parietes of the thoracic cavity, or on the organs within it.

1st. The changes in the substance of the heart giving rise fissures, are produced principally by inflammation , ulceration , and gangrene, {2) which soften this substance, (3) and gradually destroy it in one or more parts, so that there is finally a solution of continuity during the systole or the diastole. One can imagine that this species of fissures is equally frequent in all parts of the heart.

2d. Those on the contrary which depend on morbid changes supervening in the arterial trunks occur in some points more frequently than in others, and are probably more common in one sex than in the other.

p. 95, and 101), throws great light on the theory of the formation of polypi of the heart, inasmuch as we can no longer doubt that their organization takes place in the same manner as that of the false membranes, and depends en the same cause.

F. T.

(1) Bland, Mémoire sur le déchirement sénile, du cœur, in the Bibliothèque médicale , vol. lxviii. p. 364.— Rostan, Mémoires sur les ruptures du cœur, in the Nouveau, journal de mêdicine, vol. viii. p. 265. — A. J. L. Bayle, Observation de rupture du. cœur, in the Revue médicale, vol. iii. p. 96.— Carrier, Observation sur une double rupture des parois du ventricule gauche du cœur, in the Journ. univ. des sc. médicales, vol. xxxv. p. 358.

(2) Although, strictly speaking, gangrene of the heart is not impossible, it is at

least so rare that those observers in whom the fullest confidence can be placed have not seen it. Thus Corvisart does not hesitate to say that no well authenticated case of it exists. Most of the facts which have been reported, being stated in a faithless manner, should be reeeived only after strict examination and admitted with distrust. Such is the very wise opinion of Bertin ( Des malad, du cœur, p. 408), who thinks that these facts should be considered as acute softenings of the heart rather than real gangrenous affections. F. T.

(3) Laennec first called the attention of pathologists to softening of the heart, of

which he admits two species, one where the substance of the organ is more deeply colored, and the other where it is discolored, or rather has a whitish or yellowish tinge ( De l’auscultation, vol. ii. p. 186). He asserts that he has found this softening in all cases of fevers called essential, when he has attended to them. He does not however consider this as a character of inflammation. Bertin thinks it is caused by inflammation of the heart, which is acute when it is of a deep red or even brownish, and chronic, when the muscular tissue of the organ is discolored and becomes pale or yellowish. F. T.


ANGEIOLOGY,


21Ÿ

Thus the part of the heart most frequently ruptured is the left ventricle, and this accident is more common in the male than in the female, because the ossification of the valves and the contraction of the arterial orifice, which is a consequence of it. are observed in the left more frequently than in the right, and in the male oftener than in the female. When this occurs, the substance of the heart is thinner less frequently than it is thickened and hardened.

The normal difference between the right and left portions of the heart also accounts for the greater frequency of the fissures on the left side, since the right side is less tense and more extensive than the other.

The normal arrangement of the heart explains also why fissures occur in one part of the ventricles rather than in another.

This point is commonly the place where the arterial trunk unites to the ventricle,(l) because there is no continuity in this place between the fibres of the heart and those of the arteries.

The place where fissures occur most frequently, next to this, is the apex of the heart, as there the substance of the organ is thinnest.

Contusions of the chest or the forcible penetration of foreign bodies, as of musket-balls, also tear the heart, even when the parts surrounding this viscus are uninjured.

Besides these fissures, which are visible externally and which pass through the heart entirely, there are others which are much less frequent, and where either the tendons of the venous valves or the fleshy pillars are detached from their points of insertion. The latter almost always result from violent efforts or emotions.(2)

Wounds of the heart are or are not attended with the presence of • the wounding body. In both cases they pass through all the substance of the organ or affect only its surface. Wounds attended with the presence of the foreign body are seen principally after musket-wounds, when the ball, not having power enough to pass through the- heart, remains within it or probably insinuates itself by degrees, the wound cicatrizing behind it as it advances. In both these cases the individual has sometimes survived so severe an injury, but this is rare. (3)

(1) This assertion is not correct. Ruptures of the heart occur always, or most

generally, toward the apex and the anterior part, that is, in the thinnest part. In tins respect, Rostan has observed that the disproportion of the diameter is such, that often, when the diameter of the upper part of the ventricle is sixteen or eighteen lines, which he asserts is the greatest development which it can attain, the apex is only two lines thick. Bayle has mentioned, that of nineteen instances of rupture of the heart, fourteen existed in the left ventricle, principally its anterior face near the apex, three in the right ventricle, one in the apex, and the other in the interventricular septum. In most of the cadavers the heart was remarkably soft, and in some cases a brownish color was observed around the perforation. These two circumstances support Bertin’s opinion, who (Des maladies du cœur) thinks that the preceding erosive inflammation plays an important part in these perforations, as in those of the stomach and intestines. P. T,

(2) Corvisart, loc. cit., p. 256, De la rupture partielle du cœur.

(3) We find an instance of the first case in the Diet, des sc. méd. vol. iv. p. 217, and one of the second in Penada, Saggi sc. di Padova, vol. iii. part 2, p. 59.

Vol II 28


218


DESCRIPTIVE ANATOMY.


Penetrating, cutting, or pricking wounds are always and almost immediately mortal.(l) In order to conceive of a contrary case, we must admit that the wounding instrument penetrates gradually. (2)

§ 1325. Most of the deviations in form in the inner parts of the heart are congenital. They comprise, 1st, those which cause no derangement except in the circulation of the blood ; 2d, those which derange the formation of the blood.

§ 1326. The deviations of form in the first class consist principally in the abnormal arrangement of the several orifices of the heart.

Among these are :

1st. The abnormal narrowness of the venous orifices of the ventricles .(3) This anomaly occurs most frequently on the left side, and is not rare. The mitral valve is then always thickened, more or less hardened, and often ossified. It is very doubtful if this anomaly ever be congenital. At least it is not so generally.

2d. The abnormal narrowness of the arterial orifices of the ventricles This congenital aberration occurs most frequently on the right side, and almost always results from a contraction, often also from an adhesion of the valves.

(1) Wounds of the heart are generally mortal after a few moments, or at most some hours. Some wounded persons have been known to survive one or five, seven, thirteen, seventeen, and twenty days, after penetrating wounds. See the surgical part of tire article Cœur, by Begin, in the Diction, abrégé des sc. medic., vol. iv. p. 493.

F. T.

(2) Although it did not form apart of our author’s plan to speak of the alterations

in the texture of the heart, we think it necessary to say a word upon its hardening, the theory of which appears to be intimately connected with that of its hypertrophy, its polypi, and its softening, that is with its irritation more or less approaching to the degree usually considered as inflammation. General hardening of the heart has not yet been noticed ; but it may be more or less extensive and sometimes invade an entire half of the heart. It is often confined to the internal or external face, where it is presented under the form of incrustations. The fleshy columns and the septum may also be the exclusive seat of it. It presents several degrees. Simple hypertrophy is the first and ossification the last. There are different shades between these two extremes ; sometimes the substance of the heart, of a bright red color and almost healthy in appearance, resembles in hardness a fibro-cartilage, and resists or grates when cut : sometimes it presents a cartilaginous density and solidity : again it is still harder and sounds like horn, as Corvisart says ; sometimes it resembles earth or sand (Bertin, Des mal. du cÅ“ur, p. 401). Ossifications of the heart are not rare in man. Meckel has collected several instances in his Dissertatio de cordis conditionilus abnormibus, Halle, 1802, and in his Manual of Pathological Anatomy. It is curious that in many animals, especially in the ruminantia, there is very often a bone in the heart. This has long been known in regard to the ox and the stag. See on this subject Keuchen, Diss. de ossiculis c cor dibus animalium, Groningen, 1772. — Jaeger, lieber des Vorkommen eines Knochen im Herze des Hirsches; in th e Deutsches Archiv für die Physiologie, vol. v. p. 113. — F. S. Leuckart, Bemerkungen über den Herzknochen des Hirsches ; same journal, vol. vi. p. 136. — We think it worthy of mention, however, that Masuyer has found 1,7 of phosphoric acid, 2 of uric acid, 3 of animal matter, 5,3 of lime, in twelve grains of the ivory substance coming from the ossification of the valves of the heart, from its external face at the base of the right ventricle, and from the aorta, and also from the large branches which arise from it (Journal de la société des sciences, agriculture, et arts , de Strasbourg, 1824, No. 3). The presence of uric acid in this case is remarkable as an analogy with what is seen in arthritic concretions. F. T.

(3) Abernethy, On a diminution in consequence of disease of the area of the aperture, by which the left auricle of the heart communicates with the ventricle of the same f in the Med. chir. trans. vol. i. p. 27.


A.NGEIOLOGY,


219


od. The deficiency or adhesion of the valves, especially those of the arteries, sometimes occurs, and is not generally congenital but accidental. The absence of the valves is caused by their destruction by suppuration, and their adhesion results from inflammation and ossification.

4th. Jin excess or deficiency in the number of the valves , which is seen particularly, but yet seldom, in the pulmonary artery, and much less frequently in the aorta. We find four valves more commonly than two.

§ 1 327. The essence of the deviations in form of the second division is an abnormal communication between the systems of red and black blood. They have no influence on the formation of blood, or when they possess it, the arrangement is such that the black blood becomes less venous or the red blood less arterial. In both cases the abnormal union of both the systems of blood may take place in very different parts.

1st. The abnormal communication of the first kind depends,

a. On the insertion of one, of several, or of all the pulmonary veins in the vena cava superior. We have a case of this kind before us.

b. On the existence of an accessory pulmonary artery, which arises from the ascending aorta.(l)

2d. The abnormal communications of the second kind occur either between the auricles, or the ventricles, or in the large vascular trunks. Many or all these anomalies are not unfrequently combined in the same subject.(2)

a. The most simple form is a single heart, consisting of one muscular cavity.

b. Next follows the formation where only one auricle and one ventricle exist, whence a single vessel, the aorta, arises, from which the pulmonary artery branches off, while the pulmonary veins open into the auricle, or even, by a formation still more abnormal, into the vena cava superior.

The formation is more perfect when the heart is divided by a septum into two halves, and the aorta and the pulmonary artery arise by separate trunks, but the septum is imperfect.

c. In this case the septum of the ventricles and of the auricles is perforated and the foramen ovale is open, which is the case most frequently; or,

& Only the septum between the ventricles is perforated, a more un, frequent formation ; or,

e. Only the foramen ovale is open ; this is the most usual.

(1) We have collected all the known cases of this anomaly, in the De monstrodà duplicitate, p. 55, and in Handb. der pathol. Anat., vol. ii. p. 134.

(2) The different degrees and in general most of the species of this class of anomalies are described in our Handbuck der pathol. Anat., vol. i. p. 422-470, vol. ii. p. 133, 134. — Farre, Pathological researches, Essay 1, On malformations of the human hears, London, 1814.— J. C. Hein, De cordis deformationibus quce san g-uinem. renosum cum. arterioso ipisceri permittunt , Gottjngen, 1816.


220


DESCRIPTIVE ANATOMY.


The septum of the ventricles is perforated generally in one deter tm nate place, viz. the base ; so that sometimes the aorta, sometimes but more unfrequently the pulmonary artery, arises from both ventricles : in the latter case the aorta arises as usual, but forms only an ascending portion, and terminates in the left subclavian artery, and the descending aorta comes entirely from the pulmonary artery.

The interauricular septum is frequently developed imperfectly, that is, its formation has not followed the course mentioned above (§ 1305), but the pressure of the left auricle can then complete it ; so that the passage of the blood from this auricle into the right becomes impossible. Sometimes however, but more unfrequently, from the absolute or relative smallness or deficiency of the valve of the foramen ovale, this opening is so large, that the right and left auricles communicate freely. This. continuance of the foramen ovale is more unfrequent than the perforation of the septum, although its imperfect closure, produced in the manner stated above (§ 1305), is an anomaly still more frequent than this.

The abnormal arrangements of the large vascular trunks, which render the hematosis imperfect, are,

f. The obliteration or the considerable contraction or deficiency of the pulmonary artery, states which commonly but not always attend one of the anomalies mentioned above.

g. The continuance of the arterial canal, which seldom occurs alone, but is generally attended with one of the anomalies already described Or which remain to be mentioned.

h. The existence of a second pulmonary artery, which arises from the right ventricle and terminates in the aorta. Finally,

The transposition of the origins of the arterial or venous trunks, viz.

i. The origin of the pulmonary artery from the left and of the aorta from the right ventricle, while the venous trunks empty themselves in their proper places.(l)

k. The insertion of the veins of the body into the left portion of the heart, or into the pulmonary veins, or frequently into the pulmonary artery. This occurs in different ways. We have before us a preparation where the large coronary vein of the heart, instead of terminating in the right portion, opens into the left auricle of the heart. In another case, the vena azygos is divided near the heart into two branches, one of which goes to the right, the other to the left auricle. Sometimes the pulmonary arteries evidently anastomose with the azygos vein.

The physiological influence and importance of these anomalies are not the same.

In the first point of view, we may state it as a principle, that the first six arise because the formation of the heart is arrested at an early period of development, and because it is a repetition of the formation of the

(1) Tiedmann has described and figured a case of this anomaly in the Zeitschrift Physiologie,' ch. i. p. Ill, pi. 7, fig. 9.


ANGEIOLOGY.


22 L


heart in some of the lower classes of animals, particularly the crustaceous animals, the mollusca, and the reptiles. The others are normal in no period of life, but belong to the class of anomalies which affect the quality of the organs.

Hence also why the former are more frequent. The influence on the hematosis is much more injurious, the greater the mixture of the black and red blood : it is very slight either when the abnormal communication is merely by the small vessels ( k ), or when the communication is interrupted by the arrangement of the parts at the moment when it might be injurious : this occurs in most cases where the foramen ovale becomes open. The derangement is very great in other cases.

The effects which result from them are, frequent recurrence of asthma, extreme weakness of the voluntary muscles, great debility in the nervous system, often a defect in nutrition and development, and a blue color of the body. Death usually supervenes in the early periods of life, although in a few rare cases the patient has lived till the age of fourteen. At certain periods, especially during dentition and at the age of puberty, the symptoms recur more frequently and with greater violence. The cause of these symptoms and the essence of the derangement is, the mixture of venous with arterial blood and the distribution of this mixed blood in the body ; they arise sometimes, as for instance when the pulmonary artery is entirely closed or does not exist, or when the pulmonary artery arises from the left ventricle and the aorta from the right ventricle, because the organs of the body receive pure venous blood.

From the blue color of the skin, which depends upon the venous blood not being changed into arterial blood, (1) this disease has been termed cyanopathia ( morbus r.Å“ruleus , cyanopathia , cyanosis). ( 2)

(1) Bertin has very properly remarked that this explanation cannot be -admitted,

for three reasons : 1st, because cyanosis did not exist in cases where the right and left heart communicated ; 2d, because it did exist in other cases where this communication did exist ; 3d, because that if the blue color of the skin was produced by this deviation of formation, it ought to exist also in other parts, which is not the case. Besides, as Fouquier justly remarks, the skin of the fetus, in which only black blood circulates, is not blueish. Bertin thinks then that the blueish color of certain parts, in different individuals where the two hearts communicated, depends on the stagnation of the blood in the right cavity and in the venous system, which is in a manner gorged with it ; this explanation seems more rational, inasmuch as this anomal v in the formation of the heart is often attended with a contraction of the orifices or of the pulmonary arteries. F. T.

(2) Kwiatkowski, Diss. actiologiammorbi cærulci amplifie ans, Wilna, 1816. — Hein, Diss. de istis cordis deformationibus quÅ“ sanguinem venosum cum arterioso misccri. permittunt , Gottingen, 1816. — J. F. Meckel, Essai sur les vices de conformation du cÅ“ur qui s' apposent à la formation du sang rouge ; in th e Journ. complêm. des sc. med., vol. iii. p. 224-301. — Gintrac, Observations et recherches sur la cyanose, ou maladie blue, Paris, 1824. — Louis, Observationes suivies de quelques considerations sur la communication des cavités droites avec les cavités gauches du cÅ“ur ; in the Archives generales de médecine, vol. iii. p. 325, 485.

BESCRIPTIVE ANATOÿn.



SECTION II.

ARTERIES OP THE BODY OR OP THE SYSTEM OP THE AORTA


CHAPTER I.

GENERAL EXPLANATION OF THE SITUATION OF THE TRUNK.

§ 1328. The aorta arises most generally and with but few excep • tions by one single stem from the upper part of the left ventricle. At its origin the fibrous membrane is much thinner than in the rest of its extent ; but it is not entirely destitute of this membrane, the thinness of which is supplied by the muscular fibres of the heart, which extend some lines over the valves of the aorta, and the triangular spaces which exist between them. At its base are three sinuses, which correspond to the valves. It goes to the right, first its right side, and then the whole artery passing behind the pulmonary artery, which covers its origin : it comes afterwards on the right side of this artery, and describes a curve before the vertebral column, which is called its urch ( arcus aortÅ“). The transverse portion of this arch, the part between the right and left sides, is situated opposite the third and fourth dorsal vertebræ.

At the origin of the arch the aorta is entirely inclosed in the pericardium ; but it gradually leaves this membranous sac ; so that most of the arch is entirely loose. We observe on the left the pulmonary artery, which proceeds along the lower part of the arch of the aorta, behind it the right branch of this artery, on the right the vena cava superior, and in front the sternum.

In old age, the lower and ascending part of the arch of the aorta is more or less dilated : it does not form a perfect cylinder ; but it advances farther and projects more to the right than in early life. This change probably depends on a mechanical cause, — the continual impulse of the blood.

The central part of the arch of the aorta is situated before the lower extremity of the trachea, and the curve terminates behind the left branch of the pulmonary artery and the bronchia of the same side, in which place the direction of the artery changes and proceeds from above down â–  ward.

The ascending part of the arch is situated on the right of the vertebral column, the transverse portion directly before it and the descending portion on the left : the latter is situated in the posterior mediastinum.


ANGEIOLOGY. 22ÿ

The trunk of the aorta remains on the left of the vertebral column in all its extent.

The ascending portion of the aorta in the cavity of the thorax, called the thoracic aorta ( aorta thoracica ), is directly covered on the left by the inner wall of the left pleura, on the right by the esophagus, and forward first by the left bronchia, then by the posterior part of the pericardium.

At the diaphragm the aorta separates from the esophagus behind, passes through a special openingin this muscle ( hiatus aorticus)(§ 1072), comes into the abdomen, and is called the abdominal aorta ( aorta abdominalis). The latter descends as far as the fourth or fifth lumbar vertebra, where it divides into two branches. It is attended on the right by the vena cava inferior, rests behind on the lumbar vertebrae, and is covered both before and on the left by the peritoneum.

Above and below, it divides in an analogous but not in the same manner, since it gives off, 1st, at its two extremities, the vessels which go to the extremities ; 2d, and besides, at the upper extremity, the carotid arteries ; 3d, at the lower extremity those which supply the pelvic viscera with blood.

The vessels of the thoracic and abdominal viscera, and most of those which are distributed to the parietes of the thorax and abdomen, arise directly from the part between its two extremities.

That part of the aorta between its origin from the heart and that of the left subclavian artery (§ 1335), is called the ascending aorta ( aorta ascendens ), the remaining, the descending aorta ( aorta descendens).

§ 1329. The aorta rarely varies from this general arrangement. Nevertheless it may, in the following modes :(1)

1st. The slightest aberration is when the aorta goes backward too soon, passing immediately on the right bronchia.

Then it sometimes reaches the left side, gliding behind the esophagus and the trachea, as we have observed ;(2) sometimes it remains on the right in a greater or less extent of the vertebral column, for instance, to the base of the chest.

This anomaly may be considered as the first degree of the lateral inversion of the aorta, in which its arch curves more or less from left to right instead of describing its usual curve from right to left.

The arteries which arise from it are also modified in a similar manner ; for we sometimes find four trunks ; sometimes an innominata trunk exists on the left side and two other trunks on the right.

2d. The anomaly is greater when the trunk of the aorta tends to divide. This deviation of formation presents several degrees.

(1) O. Bernard, IHss. de arteriarum e corde prodeuntium aberrationibus , Berlin, 1818.

(2) This anomaly has been seen also by Abernethy (Phil, trans., 1793, p. 59-63)j and twice by Caillot (Bullet, de l’Ec. de Med., 1807, p. 21-28).


224


DESCRIPTIVE ANATOMY.


а. Sometimes the aorta is single at its origin ; but, some inches farther, it divides into two trunks, which pass one before, the other behind, the trachea, and afterwards unite to give rise to the descending aorta, forming in this manner a ring around the air passage. Hommell has described a curious case of this kind.

б. A greater degree of this deviation of formation exists as in the case reported by Malacarne.( 1 ) In fact the aorta is single at its origin ; but from this point even, its increased size, its oval form, and its five valves, indicate a division which occurs almost immediately. The two branches on the right and on the left give off, first the subclavian, then the external carotid, and finally the internal carotid, artery , they remain distinct from each other for about four inches, and then they unite to form the descending aorta.

This division of the largest artery of the body is curious in this respect, that it is evidently a repetition of the formation of reptiles, a class of animals in the different orders of which these anomalies constitute the normal state. It leads also to the third kind of anomaly.

3d. In this species of anomaly there is no arch. The aorta divides at its origin into two trunks, one right and ascending, which produces the subclavian and carotid arteries ; the other descends and is the pectoral and abdominal aorta. (2)

§ 1330. The aorta presents anomalies not only at its origin, but also in the rest of its course. Thus, the lower extremity of the arch is sometimes very much contracted(3) or entirely closed(4) in a slight extent ; and although the artery does not divide in this place into two large trunks, the circulation however continues by collateral vessels, which are very much enlarged.

Similar anomalies are observed also, but less frequently, in the lower part of the aorta. Thus sometimes the artery bifurcates higher than usual, to give rise to the primitive iliac arteries, which, before they divide into two large trunks, communicate by a transverse branch. (5)

CHAPTER II.

ARCH OF THE AORTA.

§ 1331. From the arch of the aorta, or from the ascending aorta, arise first, the coronary arteries of the heart ; next, at a certain distance from them, the arteries of the upper extremities and of the head, which come from its upper and transverse part.

(1) Osserv. di chirurgia, vol. ii. p. 119, tab. i. f. 1, 2. — Auctuarium obs. et. icon, ad ostcol. Padua, 1801, tab. iii.

(2) Abhandlungen der Joseph. Akademie , p. 1. tab. vi.

(3) Paris, in Desault, Journ. de. chir., vol. ii. p. 107, 110.

(4) Steidele, Sammlung chirurgischer Beobachtungen , vol. ii. p. 114, 116. — Graham, in the Alcd. chir. trans., vol. v. no. xx. — Cooper, in Farre, loc. cit., p. 14.

15) Pctsche, Sijllog. obs. anat. select ., § 77.


ANGEIOLOGV


22p


ARTICLE FIR SI'.

I. CORONARY ARTERIES OF THE HEART.

§ 1332. The coronary arteries («Æ. coronariÅ“, cardiacÅ“) arise directly above the origin of the aorta, and normally above the upper edge of the semilunar valves, so that their orifices, which correspond to the central part of these valves, are not closed when these valves are pressed against the parietesof the aorta. There are usually two, and not unfrequently three ; the third, which is generally smaller than the others, then arises, not above a special valve, but above and very near one of those to which the other two correspond. We once have found four coronary arteries, of which the two supernumerary arte* ries were much smaller than the others, and only branches prematurely detached from them.

A single coronary artery is much more rare. We have seen this anomaly which however is indicated by the less distance between the origins of the two arteries in some subjects, or in the extreme smallness of one of these vessels, the branches of which are entirely replaced by those of the other.(l) The existence of one coronary artery is curious, as it establishes a relation with the normal formation of the elephant.

But however this may be, each ventricle has a coronary artery which almost exactly corresponds to it.

§ 1333. The right , upper , or anterior coronary artery (A. coronaria anterior , s. inferior , s. dextra) is generally but a very little larger and rarely smaller than the left. It arises from the anterior part of the aorta, above the anterior valve, passes under the pulmonary artery, between the upper part of the right ventricle and the right auricle, being covered by the latter, goes forward to the right, and downward in the groove at the base of the heart, turns around the pulmonaiy auricle, and thus arrives at the lower face of the heart, and terminates in the inferior groove of its septum.

In its course it gives off at right angles, both on the right and left sides, several branches, which are often very much curved.

The right branches are smaller and are distributed to the right auricle ; the left, which are larger, go to the right ventricle, and descend longitudinally on its surface to its apex.

The longest of these descends in the inferior groove of the septum., where it anastomoses by several branches with the left coronary artery.

Other ramifications always exist, which are smaller, and are distributed on the anterior part of the left ventricle, and also commun

(1) Barclay (foe. cit., p. 6) has seen the right coronary artery so small thafPit did not extend to the left as far as the septum, and was replap^d o.a this sjde by the transverse branch of the left cöronary artery.

Vor.. IT. 29


(


JD INSCRIPTIVE ANA T O Al Y .


226

uicate with those of the left coronary artery on the flat side of tue heart.

This artery belongs principally to the right half of the heart.

§ 1334 . The left, tipper, ox posterior coronary artery (Jl. coronaria sinistra, s. superior, s. posterior ) is generally smaller than the preceding, and arises between the left auricle and the posterior side of the pulmonary artery, almost always above the left sigmoid valve. It descends on the left, between the auricle and the pulmonary artery, and having attained the groove at the base of the heart divides into two or three larger branches.

Of these one, which is anterior and longitudinal, soon separates into several considerable branches, and descends along the upper groove of the septum to the apex of the heart. In its whole course it gives off branches which anastomose with those of the right coronary artery on the upper face of the right ventricle. Some of the large branches which come from it are distributed on the upper face of the left ventricle.

The second branch, which is transverse, goes backward in the groove at the base of the heart, below the left auricle, and gives several branches, which go to the upper face of the left ventricle. The largest descend along the smooth posterior edge of the heart, some on its upper and others on its lower face.

Finally, the left coronary artery terminates by several small branches, which disappear on the lower face of the left ventricle.

These ramifications, like the preceding, anastomose with the other branches of the left coronary artery and with those of the right which meet them.


ARTICLE SECOND.

OF THE ARRANGEMENT OF THE LARGE TRUNKS WHICH ARISE FROM THE UPPER PART OF THE ARCH OF THE AORTA.

§ 1335 . From the upper transverse part of the arch of the aorta arise the trunks which carry the blood to the head, the neck, the upper and anterior .part of the chest, the upper extremities, and partly to the pericardium, the mammary glands, and the lungs.

There are usually three trunks, which arise a few lines distant from each other, the common trunk, or the innominata artery ( iruncus com munis, s. innominatus) , from whence arise the right subclavian and the right carotid arteries, the left subclavian and the left carotid arteries. The innominata artery is situated farther to the right and in front of the others ; the left carotid artery in the centre and a little farther back ; finally, the left subclavian artery most on the left and farther back than the other two.


ANGEIOLüGT.


227


After birth, the origin of the left subclavian artery sometimes but not always occupies the highest part of the arch of the aorta, while in the fetus it arises the lowest. So likewise in the fetus the innominata artery occupies the highest part of the arch of the aorta.(l) The innominata artery, in ascending from left to right, is situated in front of the trachea. It is separated from the vertebral column by the longus colli muscle, and from the sternum by the sterno-thyroideus and by the left subclavian artery at its side. It is most generally an inch long, rarely longer : sometimes however it is two inches long, and then the trunk reaches the inferior edge of the thyroid gland.

The left carotid artery arises more perpendicularly on the left side along the trachea.

The right carotid and right subclavian arteries are shorter than the synonymous arteries on the left side.

The diameter of the vessels of the two sides is the same, or at least those of the right side are but. little larger than those on the left.

The innominata artery usually arises at the side of the left carotid artery ; the left subclavian artery arises from the aorta, at some distance from the latter ; but the interval between them is not always very great.

The abovementioned arrangement is the most common ; we maythen consider it as the normal arrangement. Frequently however, at least once in eight times, (2) the number of the trunks given off from the arch of the aorta varies. This number may'’ be increased or diminished. In the former case, vessels, which are generally branches, arise directly from the arch of the aorta ; in the latter case, one of the three primitive trunks or frequently all of them are blended with each other and form but one.(3)


(1) Sabatier first pointed out this difference. (See his Memoire, sur les ehavgeniens qui arrivent aux organes de la circulation du fÅ“tus lorsqu’il a commence à respirer ; in the Mem de l’Institut ; sc. phys. et math., vol. iii. p. 342.) We are however satisfied, by numerous observations, that it is not by any means constant. Thus most anatomists have disregarded it. Portal even asserts the contrary ( loc . cit., p. 185), for he states “that the trunk of the left subclavian artery opens into the aorta a little lower than the other two trunks.”

(2) Bichat’s assertion that “the arrangement of these arteries is but slightly subject to variation” is incorrect. Haller makes almostthe same statement, and with no more foundation. Nor is Barclay more correct in asserting that “ the cases are rare where a vertebral artery, a thyroid, a thymic, a pericardiac, or an internal mammary arise from the arch.” Only the anomalies of the internal mam mary artery are rare.

(3) Besides all insulated descriptions of the anomalies in the trunks which arise from the arch of the aorta, we may consult the following works, in which this question has been specially examined, and in a more or less general relation : — BÅ“hmcr, De quatuor et quinque ram is ex arcu aorta: provenientibus, Halle, 1741. — Neubauer, Descriptio anatomica arteriÅ“ innominatÅ“ et thyroideÅ“ imÅ“, Jéna, 1772.— Huber, De arcus aortce ramis ; in the Act. Helvet., vol. viii. p. 68 102. — Walter, Sur les maladies du cÅ“ur ; in the Nouv. Mêm. de Berlin , 1785, p. 57. — Malacarne, Oss. sopra alcune arterie del corpo umano nello stalo prcternaturale e nello stato morboso ; in che Osservaz. di chirurgia, ii. Turin, 1784, p. 119. — Ryan, De quarumd. arteriarum in corp. hum. distrilnitione, Edinburgh. 1810. — Kobenvein, De vasorum d'ecicrsv ahnormi, Wittenberg. 1810,


DESCRIPTIVE aNATOaj.*.


228

§ 1336. The number of the primitive trunks is increased more frequently than diminished. Most frequently we find four trunks, one more than the normal number.

This anomaly does not always occur in the same manner.

§ 1337. Our observations on this subject are principally as follow :

1st. Most generally the left vertebral artery, which is normally a branch of the subclavian artery, arises directly from the aorta. This is the most common anomaly. (1). Notwithstanding the abnormal origin of the left vertebral artery from the arch of the aorta, the number of trunks is not increased ; because at the same time the left carotid artery passes to the right and becomes a branch of the innominata artery. This arrangement is remarkable, for it announces an effort tending to bring the anomaly to the normal type of formation.

2d. After this variety, the most common is that where the inferior thyroid artery, or a portion of it, which is always the thyroid portion, arises from the arch of the aorta. This anomaly occurs on the right side more frequently than on the left, and this vessel then arises, lik e the la-ft vertebral artery, between the innominata and the left carotid artery.

Besides these, we sometimes see coming from the arch of the aorta, in no determinate place, and most generally a little before the large trunks, and not on the same hue with them,

3d. A thymic artery (•/?. thy mica), or

4th. An internal mammary artery (Jl. mammaria interna ).

Less frequently, four trunks arise from the aorta, when the right subclavian artery comes directly from the arch of the aorta. We here find many differences.

5th. The right subclavian artery arises farthest to the right, or

(1) Bichat is also incorrect in saying that ihis anomaly is more rare than an increase in the number of the trunks of the aorta by a most inferior thyroid artery. Sabatier goes even farther, for he does not mention it at all, although he states several Other anomalies which increase the primitive trunks of the arch of the aorta (Anat., vol. iii. p. 7). Portal also is silent in regard to it and only mentions the division of the trunk of the innominata among the causes which increase the number of the arteries given off directly by the arch of the aorta (Anat. med., vol. iii. p. 155). In fact, in another place he states that the left vertebral artery arises directly from the aorta ; but he adds, contrary to what is the fact, that this arrangement is very rare. Monro does not mention it when treating of the anomalies of the trunks which arise from the arch of the aorta ( Outlines , vol. iii. p. 276, 278), although he speaks of them when treating of the varieties of the subclavian artery (loc. cit ., p. 301). Soemmerring, on the contrary, very properly seems to regard it as the most frequent anomaly, and mentions it as the first case where four arteries arise from the arch of the aorta. Boyer ( Tr. d’anat., vol. iii. p. 41) asserts, that the origins of the left vertebral and of a most inferior thyroid artery are equally common and just as frequent. It has been asserted that this anomaly was more rare in the south of Germany than that of the origin of the right subclavian artery directly from the aorta. We are satisfied from observation that this is incorrect ; and we cannot agree to it, because other anatomists of great authority, particularly Haller (le. an.fasc. vi. p. 1), Neubauer {loc. cit., p. 287), Scemmerring and Boyer (loc. cit., p. 25), assert exactly the contrary, and it is refuted by comparing tho number of known cases which njcntipn the different anomgjïes în the trunks of the arch .of the aorta..'


AN'GEIOLOGY


229


6th. This, which is much more common, anses farthest to the left, below the left subclavian artery.

Between these two formations there are several degrees ; for the right subclavian artery arises

7th. Between the right and left carotid arteries ; sometimes 8th. Between the left carotid and the left subclavian artery.

Of these five anomalies, in all of which the right subclavian artery is insulated from the right carotid, the second is undoubtedly the most frequent. When it exists, the right subclavian artery generally passes between the esophagus and the trachea, seldom before the latter, and goes to the right arm.

9th. This division of the innominata artery is sometimes attended with the transposition of both carotid arteries ; so that

10 th. First the left, then the right carotid artery, next the left subclavian artery, and finally the right subclavian artery arise ; or

11th. Both of the carotid arteries and the right subclavian artery arise in their normal places, but the origin of the left subclavian artery is farther to the right.

But the separation of the right subclavian artery from the right carotid does not necessarily increase the number of the trunks ; for then both carotids are usually blended into one trunk, an arrangement to which may be applied our remarks upon the analogous union occurring when the vertebral artery arises directly from the arch of the aorta.

§ 1338. More rarely five trunks arise directly from the arch of the aorta. When this occurs,

12th. The aorta gives off, besides the usual three trunks, the left vertebral artery, and the right internal mammary artery ; (1) or,

13th. It gives off a right inferior thyroid artery, (2) or, the innominata artery divides into the right subclavian and right carotid-artery, the former arising farthest on the right ; and besides,

14th. The left vertebral artery, (3) or the right inferior thyroid artery, (4) arises directly from the aorta ; or,

15th. The right subclavian artery arises below the left, at the same time that the trunk of the innominata is divided into the subclavian and carotid arteries, and that the left vertebral artery arises directly from it. (5) Finally, sometimes, although seldom, instead of three trunks, 16th. We have six. The aorta then gives origin to the right subclavian and carotid arteries, separately; the right vertebral artery arises between them, and the left vertebral artery springs directly from

(1) Bcehmer, loe. cit. ; in Haller, Coll, diss., vol. ii. p. 453.

(2) We have seen this anomaly twice.

(3) Loder, Nonnull, arter. variet., Jéna, 1781.

14) Patsche, in Haller, Coll, diss., vol. vi. § 44.

(5) Kotjerwein, De decursu vasorurn abnorm., Wittenberg, 1813.


230


DESCRIPTIVE ANATOMY.


the arch of the aorta, between the left carotid and subclavian ar teries. (1)

§ 1339. The number of the trunks is diminished in several modes.

I7th. The left carotid artery is a branch of the innominata, or,

18th. It arises by a common trunk with the subclavian artery of the same side ; or,

19th. The first trunk divides into the two carotid arteries, the second into the two subclavian arteries ; or,

20th. The right trunk is the right subclavian artery, the left is the common trunk of the left subclavian and the two carotid arteries.

The last anomalies are as rare, as the first is common. Our observations have proved that the latter and the distinct origin of the left vertebral artery, are the most common.

§ 1340. Sometimes, when the number of the trunks is neither increased nor diminished, their arrangement varies from the normal state. Abnormal unions and divisions then exist, of which the principal are

21st. The innominata artery is divided, but the two carotids arise by a common trunk, which is implanted in the arch of the aorta, between the two subclavian arteries.

22d. The innominata artery is divided, on the right side into the subclavian and carotid arteries ; but on the left side, both of these arteries arise by a common trunk. The preceding formation leads then to a total inversion of the origin of the vessels.

23d. The innominata artery is divided, but we find a common trunk for both carotid arteries, and 2d, one for the left, and 3d„ one [for the right subclavian artery, which then arises farther from the left side than usual, most generally below the left, and goes to the right upper extremity, passing before or behind the trachea, and most commonly the esophagus.

24th. The innominata artery also gives off, besides its usual branches, the left carotid artery ; but the left vertebral artery then arises directly from the arch of the aorta, between the other two trunks.

§ 1341 . Finally, the least possible anomaly is where only the relative situations of the larger trunks which come from the arch of the aorta are changed : they are,

1st. The trunks arise uncommonly near each other. The left carotid artery then most generally approaches the innominata. This anomaly makes the transition to the union of the two carotids into one. Again, but more rarely, the left carotid artery separates from the innominata, while the left subclavian artery approaches it. This anomaly leads to another case which is rarer, where the left carotid and left subclavian arteries arise by a common trunk.

(1) This anomaly has been seen by F. Muller, formerly demonstrator at Copen baffen, who communicated it to me


ANUEIOLOGV


231


Sometimes also the three trunks are so near each other, that they in fact arise from the same surface, or form but one stem. This anomaly evidently makes the transition to that where the aorta divides, directly after its origin, into an ascending and a descending trunk.

2d. The distance between the origin of the trunks is sometimes unusually great. Thus we have found in a child two years old, the left carotid artery nearly an inch distant from the innominata ; the left subclavian artery was also nearly an inch from the left carotid ; the arch of the aorta was extremely sharp, and the left carotid artery arose from the angle formed by the union of the right and left portions.


ARTICLE THIRD

PRIMITIVE CAROTID ARTERY.

§ 1342. The primitive or common carotid artery ( Carotis primitiva s. cephalica ) ascends along the trachea, which generally separates that of the right and left sides. It usually extends to the upper extremity of the larynx, where it bifurcates, at some distance from the angle of the lower jaw, and seldom behind it. It is situated very superficially, especially its central part, so that it is most easily found there. It is covered before by the sterno-cleido-mastoideus, the sterno-hyoideus and the omo-hyoideus muscles ; the internal jugular vein and the pneumogastric nerve are on the outside, and a little in front of it ; the latter is situated between the two vessels ; inside are the trachea, the larynx, the thyroid gland, and also the esophagus ; behind it is the cervical portion of the great sympathetic nerve, the longus colli and rectus capitis major muscles, and the inferior thyroid artery, which separate it from the vertebral column. The inferior thyroid artery seldom passes before it. The primitive carotids are generally situated on the two sides of the trachea, the right a little more forward than the left ; but sometimes, particularly at their lower parts, they are placed somewhat before this canal. The right carotid artery assumes this arrangement, especially when the innominata arises unusually far on the left, and the left when it arises from this trunk. In both cases the arteries cross the interior face of the trachea. These anomalies should be known, as they endanger the carotid arteries in the operation of tracheotomy.

The primitive carotid is inclosed with the internal jugular vein and the pneumogastric nerve, in a very firm cellular sheath.

§ 1343. From the primitive carotid artery arise only small and inconstant vessels, which go to the surrounding parts, but sometimes, and not unfrequently, it gives off, especially on the right side, the superior or the inferior thyroid artery, either wholly or partially ; the latter is more common. The origin of the inferior is, in this case, towards the lower part ; that of the upper, near the upper end of the artery.


232


UESCKIPTIVE ANATOMY.


§ 1344. The common carotid artery divides, generally as hign ass the upper edge of the thyroid cartilage, into two branches, one of which, the internal carotid, supplies the brain and the eye, while the other, the external carotid, belongs to the upper part of the neck, the skull and the face. It sometimes bifurcates much higher up, opposite the upper extremity of the styloid process, but not till it has given off the larger of the longer branches of the external carotid.(l) This arrangement is very analagous to that where the primitive trunk does not divide into two large branches, but having given off the branches of the external carotid artery. (2) This anomaly consists evidently in the premature division of the trunk, while its branches are given off too soon. In some few cases the division extends much farther, and attains even the trunk of the primitive carotid. This trunk then begins to divide very soon, and it sometimes bifurcates, opposite the sixth cervical vertebra, but the two branches remain connected with each other.(3)

The distance between the place of bifurcation and the thyroid cartilage is the same at all periods of life : (4) but the distance between the bifurcation and the angle of the lower jaw is much greater in the child than in the adult, on account of the development of the teeth, so that during early life the two large inferior branches are loose for some distance.

These two branches ascend almost perpendicularly. Below they are situated directly at the side of each other. The internal is at first more superficial than the external carotid, but it afterwards becomes deeper. Their proportional volume is not always the same. The differences depend partly on the age, partly on the distribution of the external carotid artery.

In the first respect, the internal carotid artery is always larger than the external in infancy, on account of the size of the brain : in the second, the external is larger than the internal carotid in the adult, when it gives off the superior thyroid artery, and smaller than it, on the contrary, when the latter comes from the prmitive carotid.

I. EXTERNAL CAROTID ARTERY.

§ 1345. The external carotid artery ( Carotis externa, s. facialis, s. A. p encephalic a) ascends under the posterior belly of the digastricus muscle of the lower jaw, is situated between the ear and the ascending branch of the lower jaw, where it is entirely covered by the parotid gland, and divides at the neck of the lower jaw into a superficial branch, which is the temporal artery, (Jl. temporalis ) and a deeper seated

(1) Burns, Surgical anatomy, Edinburgh, 1811, p. 95, 96.

(2) Idem, ibid., p. 95.

(3) Idem, ibid., same page. — We regret that the author does not say whether the anomaly existed on the two sides or only on one side, (perhaps the left';)

(4) Idem, ibid., p. 379.


ANGEIOLOGY.


233


branch, the internal maxillary artery. ( A . maxillaris interna.) But it always gives off large branches, before it bifurcates. These branches generally detach themselves gradually, one after another. Sometimes, however, the external carotid artery forms a short trunk, which divides directly above the bifurcation of the primitive carotid into the large inferior branches, and the broad continuation of the trunk.

§ 1346. Before bifurcating, the external carotid artery gives off branches principally in three directions : forward, backward, and inward.

A. ANTERIOR BRANCHES.

§ 1347. The anterior branches are the superior thyroid artery, thtr lingual artery, and the facial artery.

1. SUPERIOR THYROID ARTERY.

§ 1348. The superior thyroid artery (A. thyroidea superior) is the lowest branch of the external carotid artery. Its origin varies : it geneerally arises some lines above the bifurcation of the primitive carotid ; but it not unfrequently detaches itself at the bifurcation, or below, and even from the trunk of the primitive carotid ; sometimes an inch below its bifurcation.

Its size also varies, and it is in the inverse ratio of that of the inferior thyroid artery. When the latter is entirely deficient, the superior is much larger than usual ; it is on the contrary very small, when the inferior thyroid artery is very large, or when the lowest thyroid artery exists.

Sometimes, but unfrequently, it arises by a common trunk, with the lingual artery, and in some subjects this trunk comes from the primitive carotid.

On the other hand, we not unfrequently find the superior thyroid artery double, because the branches which it generally gives off are detached lower than usual. The arrangement and size of the left and right thyroid arteries vary ; sometimes one of them is deficient, while the other is very large.

§ 1349. When the artery does not arise much lower than usual, nor from the primitive carotid, it always descends inward and forward, being at first slightly concave above, and very tortuous. It sometimes gives off a large branch immediately after arising, which detaches itself from its posterior and inferior part, and goes to the sterno-cleidomastoideus muscle. It then soon divides into an upper and a lower branch. Sometimes it bifurcates near or even at its origin.

The upper or laryngeal branch (ramus laryngœus ) arises from the external carotid artery, according to our observations, once in eight tim<^. It goes downward, forward and inward, on the thyroid cartilage, and frequently gives branches to the omo-hyoideus,the sterno-hyoideus, the stevno-thyroideus, the hyo-thjuoideus and the cvico-thvroidcits

Yon. II ‘ 30


234


DESCRIPTIVE ANATOMY.


muscles, which come sometimes from the lower branch, or directly from the external carotid artery : furnishes a large anastomotic vessel which goes across the cricoid cartilage, and unites with the branch given off by the synonymous artery opposite ; finally it penetrates within the larynx, passing generally between the hyoid bone and the thyroid cartilage, sometimes, but more rarely, near the upper edge of the latter, by an opening which exists there, or even between the cricoid and the thyroid cartilages.(l) Having arrived at this organ, it distributes itself upon its internal membrane, and also to its muscles, anastomoses very frequently with the synonymous artery of the opposite side, and even sends ramuscules outside of the larynx, which communicate on its surface with those of the other side, and with the ramifications of the thyroid branch.

The inferior or thyroid branch ( R. thyroideus ) is the continuation of the trunk ; it sometimes furnishes many or even all the muscular branches which we have described as coming from the laryngeal branch ; but small twigs always arise from it and go to the middle and inferior constrictors of the pharynx and to the crico-thyroideus muscle. After which it descends downward into the thyroid gland, and generally divides, at its upper extremity, into two branches, a posterior and inferior, and an anterior and superior, which soon subdivide. The former penetrates posteriorly into the thyroid gland, and anastomoses along its posterior face with the branches of the inferior thyroid artery ; the other proceeds along its upper edge, gives off considerable branches which expand on its anterior face, and anastomose, by very large vessels, with the synonymous branch of the opposite side.

When the superior thyroid artery is divided into two separate trunks it often happens, but not always, as one might think from what several anatomists say, (2) that the laryngeal branch is distinct from the thyroid branch, and situated above it. Sometimes however, but very rarely, the superior thyroid artery gives off only the trunk of the muscular branches and the laryngeal branch.

II. LINGUAL ARTERY.

§ 1350. The second branch is the lingual artery (v3. lingualis, s. sublingualis, s. ranina), which arises farther inward, most generally a few lines, and sometimes an inch, above the preceding, and rarely by a

(1) We have remarked that this is the most common arrangement ; so that our observations in this respect agree with those of Mayer (toe. cit., p, 249), and with Bichat ( loc . cit., p. 149), who both say that the laryngeal branch commonly penetrates into the larynx by passing between the hyoid bone and the thyroid cartilage. Murray (loc. cit.. p. 11) indicates exactly these three arrangements, but does not say that the first is the most frequent. Scemmerring (p. 131) entirely neglects this, and speaks only of the two which are less frequent. Sabatier (p. 115) mentions only the third.

(2) Mayer, (loc. cit., p. 49) asserts, but wrongly, that the laryngeal always arises a quarter of an inch above the thyroid artery. Sabatier (loc. cit., p. 15) ; Soemmering (loc. cit., p. 131); (Portal, foe, cit., p. 159).


ANGEIOLOGY.


235


trunk in common with the superior thyroid artery, but more frequently, and nearly once in seven times, with the facial artery. It is generally a little larger than that we have mentioned.

This artery curves considerably, and its convex part looks upward, passes then directly over the large horn of the hyoid bone, goes horizontally forward, glides between the middle constrictor of the pharynx and the hyoglossus muscle, and then ascends towards the base of the tongue, where it recommences, and then goes horizontally forward, along the inferior face of this organ.

From its posterior part arise, 1st, several branches, which go to the hyo-glossus muscle and middle constrictor of the pharynx, and which, having passed through the latter, enter the digastiicus and the thyrohyoideus muscles, and the submaxillarv gland ; 2d, a branch which goes downward and inward, between the genio-glossus and the geniohyoideus muscles directly on the hyoid bone, gives branches to these muscles, especially to the first, and anastomoses with that of the opposite side. It is called the hyoid branch (I?, hyoideus).

From the central ascending part aiise one or more dorsal arteries of the tongue ( ll dorsales linguae ), which go downward to the posterior part of the tongue, on the inside of the hyo-glossus muscle, ascend upon the back of this organ, and advance to the epiglottis.

The lingual artery divides, in front of the hyo-glossus muscle, into a ranine and a sublingual artery.

The ranine artery (A. ranina) is larger than the other, and is a continuation of the trunk. It extends deeply between the lingualis and genio-glossus muscles, proceeds forward, gives off several branches in its course, and finally anastomoses with that of the opposite side, behind the summit of the tongue, at the upper end of its frenum.

The sublingual artery (A. sublingualis ) is more external and more superficial than the preceding. It passes over the mjdo-glossus muscle, between it and the sublingual gland, gives off branches to it, to the hyo-glossus muscle, to the lingualis muscle, and to the proper membrane of the mouth, passes over the mylo-hyoideus muscle, and anastomoses with the inferior maxillary branch of the facial artery.

This artery sometimes arises from the facial.

III. FACIAL ARTERV.

§1351. The third branch, the facial or external maxillary artery [A. facialis , facialis anterior, angularis, maxillaris externa), varies in respect to its origin, size, and extent ; it is commonly the largest of the three anterior branches of the external carotid, and supplies all the anterior part of the face ; but sometimes also it extends only to the angle of the mouth, and the other branches are supplied from the temporal artery. There is scarcely a vessel which varies so much asihis. even in the two sides of the same body.


236


DESCRIPTIVE ANATOMY.


It passes under the posterior belly of the digastricus muscle to go to the angle of the lower jaw. In this place it proceeds first horizontally behind and within the inferior edge of the lower jaw, then goes obliquely upward and forward on the inside of this bone and of the upper jaw.

It frequently gives of!’, directly above its origin, the inferior or ascending palatine artery (Ji. palatina ascendens , s. inferior ), which usually arises from the ascending or inferior pharyngeal artery (A. pkanjngÅ“a ascendens) ; we shall describe it with that.

It then gives small ramuscules to the digastricus and stylo-hyoideus muscles.

Farther on, it gives off considerable branches which go to the submaxillary gland ( R . glandular es), and goes forward in one of its grooves. Farther onward, it gives off one or more ramuscules to the pterygoideus internus muscle.

It then furnishes the submental artery ( R . submenlalis). This arises near the lower edge of the lower jaw, and proceeds along it, directly below the attachment of the mylo hyoideus muscle, and over the anterior belly of the digastricus muscle, gives ramuscules to both of these muscles, anastomoses with the sublingual artery, and thus goes forward, where it communicates with that of the opposite side, on the centre of the lower edge of the lower jaw. Thence it reascends into the substance of the lower lip, to which it gives twigs, as also to the skin of the chin, and anastomoses with the descending branches of the coronary artery of the lower lip, and also with those of the inferior dentar artery, which emerges from the mental foramen.

When the sublingual artery is a branch of the facial it arises a little, and even in most cases directly before the submental.

The continuation of the trunk, or the proper facial artery, turns upon the lower edge of the lower jaw, generally directly before the anterior edge of its ascending branch, thus attains the outer face of this bone, descends very obliquely between the masseter and the triangularis oris muscles, arrives at the angle of the lips, and gives off in this place several branches, which enter the masseter, the triangularis and the buccinator muscles and the skin.

About the centre of the space between the angle of the mouth and the under edge of the lower jaw, it generally divides into two branches. One, the continuation of the trunk, goes directly upward ; the other is smaller, and proceeds more obliquely inward and forward.

The latter is the inferior coronary artery of the Up {A. coronaria labii inferioris). It passes under the triangularis oris muscle and proceeds toward the lower lip, gives several branches to this muscle, to the levator menti, and also to the membrane of the mouth, and anastomoses both with its fellow of the opposite side and with the twigs of the submental and inferior dentar artery.

This artery is sometimes much smaller on one side than on the other. In some subjects it is even entirely deficient, and is then replaced bv


ANGEIOLOGY.


237


that of the opposite side. Sometimes it arises much higher and comes from the superior coronary artery of the lip. In some cases it is double : one of the two then arises much above the other ; but the two arteries taken together are not larger than that of the opposite side : sometimes the two branches into which the lower coronary artery of the lips is divided are very small.

After giving off this branch, the facial artery winds tortuously upward and inward. Arrived as high as the angle of the mouth, it generally divides, a little above this point, into two branches.

The larger goes inward and forward, between the fibres of the orbicularis oris, and is called the superior coronary artery {A. coronaria labii superioris). This artery proceeds directly over the loose edge of the upper lip, gives ramuscules to the orbicularis oris, to the levator labii superioris, to the skin, to the buccal membrane, meets that of the opposite side and anastomoses with it by a broad communication similar to that between the inferior coronary arteries. The two coronary arteries usually anastomose together in two places by large branches : sometimes the anastomosis between the arteries is very small on one side, but is replaced by a very large branch, which arises higher up from the facial and which communicates with the artery of the septum of the nose.

Both coronary arteries are very tortuous, but the upper is more so than the lower. Both anastomose with the synonymous arteries of the opposite side, and these anastomoses are proportionally the largest in the body, when we consider the vessels between which they occur.

The superior coronary artery always gives off from its centre, where it anastomoses with that of the opposite side, a branch, which goes upward toward the nasal septum, which is called the artery of the septum of the nose {A. nasalis septi). Sometimes this artery is single, sometimes double, and even triple, at its origin : in the last two cases-it is frequently given off by the coronary artery of one side ; but however this may be, it divides near the septum of the nasal fossae into at least two branches, a right and a left, each of which proceeds along the lower edge of the septum and the inner part of the corresponding nostril to the end of the nose, and also sends ramuscules, which reascend on the cartilaginous septum.

Besides these branches, the coronary artery gives off sometimes before, more externally and on one side only, or on both, another considerable branch (R. pinnalis), which goes to the ala and the outer part of the nostril ; but this branch more frequently comes from the next one.

The facial artery, after giving off the superior coronary, consists only of a smaller branch, which may be called the common external nasal artery (A. nasalis externa communis). This artery is very tortuous, and ascends obliquely forward under the levator labii superioris muscles, to which it gives ramuscules, goes toward the nose, and anastomoses by considerable branches with the infra-orbitar artery. It


238


DESCRIPTIVE ANATOMY.


usually gives off, opposite the nostril, the lateral arteries of the nose ( R . pinnules , s. laterales nasi), and also sends off numerous smaller arterial twigs, which anastomose with each other and also with those of the septum and their corresponding ones of the opposite side, which are called the dorsal arteries (R. nasales dorsales ), and which always communicate on the nose by several large or small branches with the ophthalmic artery. Finally, it terminates on the back and side of the nose, and never, even in its greatest degree of extension, goes beyond the upper edge of the cartilaginous portion of this organ.

The two coronary and the common external nasal artery, and more frequently only the superior coronary and the latter, sometimes arise not only from the above facial but also from the transverse facial artery, which then is much larger, while the other is smaller, although the facial artery is not necessarily more developed at its lower part ; we likewise observe in other subjects that this artery is very much developed at its upper part, although the lower part does not produce more branches than usual. We have seen the sublingual artery coming from it at least several times, and the facial artery at the same time was as large as usual. In other cases, on the contrary, it gives off neither of the two coronary arteries, while the sublingual artery arose as usual ; but the submental artery was uncommonly small.

Hence it appears that the facial artery is always the principal source of communication, 1st, between the superficial and the deep-seated branches of the external carotid by its anastomoses with the infra-orbitar, the nasal, and the dentar arteries ; 2d, between the external and the internal carotid arteries by its anastomosing with the ophthalmic artery.

§ 1352. Numerous small branches, which go to the masseter and pterygoidei muscles and to the parotid gland (/i. masseterici,pterygoidei , et parotidei ), arise externally and internally from that part of the carotid artery situated between the ascending branch of the lower jaw and the ear.

A larger anterior branch, the transverse facial artery, which will be described hereafter, rarely arises from its upper extremity, directly below its division.

B. INNER BRANCH.

I. ASCENDING OR INFERIOR PHARYNGEAL ARTERY.

§ 1353. Most generally only one branch arises from the inner face of the external carotid artery ; this is the ascending or inferior pharyngeal artery {.Il . pharyngcea ascendens , s. inferior , s. posterior ), which comes sometimes from the bifurcation of the primitive carotid, somerimes from the origin of the internal carotid, but more frequently from


AN'GEIOLÃœGY.


239


the occipital artery, (1) and is sometimes replaced by the branches of the facial artery.

If it is a branch of the external carotid, it arises very deeply, most generally above the inferior thyroid artery ; so that it is the second branch from the trunk . but sometimes it comes higher up and even above the facial artery.(2)

It is sometimes double : then the two inferior pharyngeal arteries rarely come from the external carotid ; one arises from the latter, and the other from one of the secondary branches above described, or from the internal carotid artery. (3)

It is always the smallest branch of the external carotid artery.

It goes perpendicularly upward, on the inside of the external carotid artery, and in the same direction with it, between it and the pharynx.

It gives off first the descending branches to the constrictors of the pharynx, and to the anterior and lateral muscles of the neck.

A little farther it divides into two branches, one of which, the pharyngeal branch, (R. pharyngÅ“us ) is distributed principally to the constrictors of the pharynx, and communicates with the pharyngeal branches of the superior thyroid artery ; the other is termed the posterior meningeal artery, («d. meningÅ“a posterior ) ascends through the posterior foramen lacerum of the skull, or through a special opening near the occipital condyle, and is distributed to that part of the dura mater which lines the lower part of the skull.

C. POSTERIOR BRANCHES.

§ 1354. The posterior branches of the external carotid artery are, 1st the occipital , and 2d the posterior auricular artery.

1. OCCIPITAL ARTERY.

§ 1355. The occipital artery («3. occipitalis) is a considerable branch, but much smaller than the three anterior branches, which usually arise opposite the lingual or the facial artery ; seldom or never above or below them. It rarely comes from the internal carotid artery. It is very deeply situated ; goes upward and backward, often gives off, soon after arising, branches which go to the posterior belly of the digastricus muscle of the lower jaw, then a descending branch, which

(1) Scemmerring states that it sometimes arises from the superior thyroid arterjL AVe have never seen this, nor is it mentioned by any other anatomist, Scemmerring', it is true, quotes Mayer ; but the laryngo-pharyngean artery ( A . laryngo-pharyvgcea) described by Mayer, is the laryngeal branch of the superior thyroid artery, and describes the inferior pharyngeal artery as the posterior artery of the throat,

(2) Bichat asserts that it arises between the facial and lingual arteries. Our observations lead us to think that SÅ“mmerring is more correct in saying that it rarely arises higher than the lingual. Murray places it behind the facial, but adds that its origin is near that of the lingual. Portal also places it nearly opposite this latter, as do Sabatier and Mayer. Boyer states that it arises opposite the facial.

(3) Scemmering asserts that when it is double, the lower trunk arises from the prim tive carotid, and the superior from the internal carotid. This arrangement exists sometimes, but it is not the law. That mentioned by us is much more common.


240


DESCRIPTIVE ANATOMV.


goes to the sterno-cleido-mastoideus muscle and the upper lymphatic glands of the neck, higher up, gives off wholly or partially the ascending pharyngeal artery, then extends below and deeply between the transverse process of the first cervical vertebra and the mastoid process of the temporal bone, continues its course backward, passing under the complexus minor muscle, then assumes a horizontal direction, gives branches to the upper extremity of the sterno-cleido mastoideus, to the complexus minor, to the transversalis colli, to the small lateral and posterior muscles of the head, and then ascends on the occipital bone, covered by the upper part of the splenius muscle, to which it gives branches. It is then called the superficial occipital artery, proceeds directly below the skin, on this bone to the vertex, terminates in a large anastomosis, formed by its branches with each other and with those of the frontal, the superficial temporal and the synonymous artery of the opposite side.

At the place where the occipital artery leaves the space between the transverse process of the first cervical vertebra and the mastoid process of the temporal bone, to pass on the obliquus capitis major muscle of the head, it always gives a deep or descending branch. This branch being sometimes very considerable, and nearly as large as the continuation of the trunk, we may then admit that the artery divides at this place into a superficial and deep-seated branch. When this is the case, it descends to the middle of the back, between the splenius, complexus, digastricus and transversalis colli muscles. Sometimes, however, it is very small, and then it is distributed in the small posterior muscles of the head.

The deep-seated branch anastomoses many times with the vertebral artery, and with the cervical branches of the inferior thyroid artery.

From the superficial occipital artery constantly arise one or several branches, which pass into the cranium through the mastoid foramina ; more rarely through the large occipital foramen or the foramen lacerum, which are distributed to the posterior and inferior part of the dura mater. They are termed the posterior meningceal arteries. (A. meningeÅ“ posteriores ab occipitali.)

2. POSTERIOR AURICULAR ARTERY.

§1350. The posterior auricular artery (A. auricular is posterior) is generally much smaller than the preceding, and arises a little above it, in the substance of the parotid gland, and is generally separated from it only by the stylo-hyoidcus muscle. Sometimes it arises from this artery, and rarely somewhat higher, directly below the division of the external carotid artery into the superficial temporal and the internal maxillary artery. It goes upward, at the side and behind the trunk of the external carotid artery, and passes through the parotid gland, near the mastoid process. There it gives, 1st at its lower posterior


AN GEIOLOG Y.


241


part, branches which go to this gland, to the posterior belly of the digastricus muscle, to the stylo-hyoideus and to the upper part of the sternocleido-mastoideus muscles ; 2d, from its superior and anterior part, an ascending branch, the stylo-mastoid artery (A. stylo-mast oidea), which furnishes minuscules to the auditory passage, penetrates into the canal of the facial nerve through the stylo-mastoid foramen, distributes itself to the mastoid process, to'the tympanum, and also to a portion of the labyrinth, and anastomoses with a branch of the middle meningeal artery. The trunk of the artery then divides at the level of the mastoid process into two branches, an inferior or muscular and a superior or auricular branch.

The inferior branch goes transversely outward, over the upper part of the splenii muscles, gives minuscules to these muscles, to the trapezius and to the skin, anastomoses with the superficial occipital artery, and advances toward the occiput.

The superior branch goes upward and backward. It usually divides into two or three branches, one of which, the more transverse, goes backward to the mastoid process, and gives branches to it, also to the occipitalis muscle ; while the other, or the others, attain the posterior part of the concha, distribute the small arteries to the retrahentes auriculæ, and to the transversus auriculae muscles, then pass over the concha, and thus come on its internal face, where they lose themselves in the skin and the mucous membrane.

D. TERMINATION OF THE EXTERNAL CAROTID ARTERY.

§ 1357. The external carotid artery terminates at the neck of the lower jaw in two trunks, a superficial, the temporal artery ; the other deep-seated, the internal maxillary artery.

I. TEMPORAL ARTERY.

§ 1358. The temporal artery (A. temporalis) is smaller and more superficial than the internal maxillary, and continues in the direction of the trunk. It goes upward and outward. Its branches may be divided into anterior and posterior.

The anterior branches are principally the following :

1st. The first branch is often the upper masseteric artery (A. masse, terica superior ) which penetrates sometimes to the external and sometimes to the internal layer of the masseter muscle, but frequently comes from the next.

2d. The transverse facial artery (A. transversa , s. transversalis faciei){ 1) is the second, often the first branch of the artery, and arises

(1) Scemmering ( loc . cit.. p. 196) mentions it as arising from the external carotid artery, before it bifurcates, and says also that it sometimes comes from the internal carotid artery, and cites as authorities Mayer, Murray, and Walter. But Murray states expressly that it is the fourth branch of the external temporal artery (p. 17).

Vol. II. 31


242


DESCRIPTIVE ANATOMY.


directly above the bifurcation of the external carotid artery. Sometimes, but unfrequently, it arises from the external carotid artery, and most generally from the bifurcation. It goes forward, with the canal of Stenon, on the masseter muscle, directly below its upper edge, gives off the superior masseteric artery, when this does not come from the temporal artery, sends several minuscules to the skin, penetrates forward into a greater or less portion of the orbicularis palpebrarum muscle, and anastomoses, by a considerable number of ramifications, with the facial artery, which it meets, and with the infra-orbitar artery. Sometimes this gives off all the upper part of the facial artery.

In some subjects its ascending minuscules extend much higher, and reach the outer extremity of the edge of the orbit.

The middle temporal artery ( A . temporalis media) generally arises some lines above the transverse facial artery, a little below the malar bone, a considerable branch, which proceeds first from below upward, gives off one or several minuscules to the upper part of the masseter muscle, then curves backward at a right angle, between the trunk and the temporal muscle, and terminates partly in small twigs, which penetrate into the substance of the muscle where they anastomose with those of the deep temporal artery, and partly in superficial branches, which are distributed on the auditory passage, where they communicate with those of the posterior auricular artery.

After giving off this artery, the trunk of the temporal artery goes upward and forward, on the temporal muscle, directly under the skin, and describes a considerable arch, which is convex posteriorly and terminates as the anterior temporal artery (Jl. temporalis anterior ), anastomosing several times with the superciliary artery, and giving branches to the frontalis muscle, and to the skin of the forehead.

Small inconstant branches come from the anterior and concave part of the arch which it describes, these go forward into the outer part of the orbicularis palpebrarum muscle, and communicate with the ascending branches of the transverse facial, and also with the upper minuscules of the anterior temporal artery.

The posterior branches of the superficial temporal artery are,

1st. The anterior inferior auricular arteries (Jl. auricular es anteriores inferiores ), usually three or four in number, which arise directly above one another from its lower part, and are expanded in the inferior and anterior part of the concha.

2d. The anterior and superior auricular artery {Jl. auricularis anterior superior) which is often single, rarely double ; it arises nearly opposite the preceding branches, and goes to the upper and anterior part of the concha, and to the attollens auriculae muscle.

Mayer describes it as the tenth branch of the external carotid artery (p. 84), but asserts positively that it arises about a line above the internal maxillary artery. The descriptions of Portal (p. 186), Boyer (p. 42), Bichat (p. 152), and Menon (p. 267), agree, like that of Murray, with the results of our observations.


ANGEIOLOGY.


243


3d. Two or three larger branches usually go backward, inward, and upward, and anastomose with each other and with those of the opposite side, and with the superficial occipital artery, which sometimes partly replaces them. They are called the posterior temporal arteries ( A . temporales posteriores'), and they are usually wrongly considered as forming, in opposition to the anterior temporal artery, but one branch.


II. INTERNAL MAXILLARY ARTERY.

§ 1359. The internal maxillary artery {A. maxillaris interna , A. orbito-maxillaris) is larger than the preceding, but differs more from the direction of the primitive trunk, and is situated more deeply, so that it cannot be seen entirely till the zygomatic arch and the outer part of the body of the upper maxillary bone is removed.

Its direction changes several times in its course. First, it goes transversely inward and a little forward, behind the neck of the jaw ; then it goes directly inward, and passes between the two pterygoidei muscles, or curves again a little forward. Arrived at the pterygoid process, it goes perpendicularly upward, over the pterygoideus extern us muscle, and is reflected on itself as high as the floor of the orbit, so that its direction becomes horizontal. Thence it divides into several branches which descend more or less, by which it terminates, distributing itself on one side on the inner and posterior part of the nose, on the other to the outer part of the face.

Proceeding in this manner, it distributes the blood to the dura mater, to the internal ear, to the pterygoidei muscles, to the temporalis muscle, to the teeth, to the interior part of the nose, to the upper part of the pharynx, and to a part of the face, and communicates with several branches of the external and internal carotid, by the following branches, which are successively given off. It usually sends one or two to the ear, viz :

a. The deep-seated auricular artery (A. auricidaris profunda), which goes to the organ of hearing.

b. The artery of the tympanum (A. tympanic a), which is distributed to the temporo-maxillary articulation, and then penetrates into the cavity of the tympanum, through the fissure of Glaser. These two branches often arise from the external carotid artery, or from the facial or temporal artery.

c. The small meningeal or the external pterygoid artery ( A.meningca parva, s. pterygoidea externa ) is an inconstant branch, which often arises from the middle meningeal or from a pterygoid artery ; it gives bmnches to the pterygoidei muscles, to the muscles of the soft palate, and to the dura mater, near the sella turcica, and sometimes penetrates into the skull through the foramen ovale.


244


INSCRIPTIVE ANATOMY.


d. The middle , or great meningeal , or spheno-spinal artery (./?. méningée i media , s. magna , s. spmosa),(l) is the largest branch of the internal maxillary artery.

It arises from the upper part of the origin of the internal maxillary artery. It goes directly upward and gives off branches to the pterygoid ei muscles, to the upper constrictor of the pharynx, to the temporal muscle, and to the muscles of the soft palate ; these are sometimes, although rarely, deficient. When they do not exist they are replaced by the small meningeal artery.

The artery then, either simple or divided, enters through the sphenooccipital hole of the sphenoid bone, into the skull, and then gives off some ramifications posteriorly, which glide into the fissure of Fallopius, penetrate into the cavity of the tympanum and the canal of the facial nerve, are distributed to the membrane of the tympanum, to these nerves, and to the muscles of the tympanum, and anastomose with the stylomastoid artery. Others, which are anterior, sometimes penetrate into the orbit, through the malar bone or the large wing of the sphenoid bone, and to the lachrymal gland. But this trunk, covered on the outer face of the dura mater, above which it projects, and of which it is the largest artery, expands principally in- the anterior and central part of this membrane. It arises, near the anterior edge of the parietal bone, at the median line of the skull, and gives off, forward and backward, numerous branches, which anastomose with the other branches of the middle, and also with those of the anterior and posterior meningœal arteries.

Besides, these branches communicate also with those of the temporal and occipital arteries.

As they project above the dura mater, and follow the grooves of the skull-bones, these indicate their course very well.

e. The inferior maxillary or inferior denial artery (A. maxillaris , s. alveolaris , s. dentalis inferior ), which sometimes arises from the middle meningceal artery, and always comes from the lower point of the origin of the internal maxillary artery, descends between the two pterygoidei muscles, to which it gives twigs, and also sometimes to the temporal muscle : penetrates into the dental canal, through which it passes forward, gives ramifications to all the teeth and to all the lower dental nerves, which occupy the same canals as they do, then emerges from the mental foramen, and anastomoses above with the inferior coronary or labial, and below with the submental artery, and produced, like the preceding, by the facial artery.

(1) Some anatomists, as Sabatier, Boyer, and Bichat, state that it is the first branch of the internal maxillary artery. We have always seen it preceded by one or more of those we have mentioned, and we have never found it, as Mayer states, arising directly from the bifurcation of the external carotid artery. According to our observations, it does not normally arise before the inferior dentar artery, as SÅ“mmering, Murray, and Munroc assert. We have seen that Portal was correct in saying that it is given off as frequently after it. or at least opposite to it.


ANGEIOLOGY.


245


This emerging branch most commonly arises at some distance from the mental foramen, within the dental canal, and on a level with the small malar teeth, at the place where the inferior maxillary artery bifurcates to produce it and the continuation of the trunk.

f g. Two or more cleep-seated temporal branches {ll. temporalis profundi ) arise from the upper part of the maxillary, and are distributed to the buccinator and the pterygoidei muscles, and especially to the temporal muscle ; penetrate also into the orbit, where they send branches into the lachrymal gland and the eyelids, and anastomose extensively with the ophthalmic artery.

h. The masseter artery ( R . massetericus) is not constant, and arises sometimes from the external temporal, or even the external carotid, or finally from one of the deep pterygoid arteries. It passes over the semicircular notch of the lower jaw into the upper part of the masseter muscle. It gives branches also to the temporal muscle, and to the two pterygoidei muscles, especially to the external.

i. The buccal artery {Ji. buccalis, s. buccinatoria ) is a very constant branch, although it often arises from the deep temporal artery, or from one of the following branches. It comes from the lower part of the inferior maxillary artery, goes downward and forward, along the outer face of the body of the upper jaw, distributes its branches in the buccinator muscles, the muscles of the upper lip, the lower part of the orbicularis palpebrarum muscle, the buccal membrane, sometimes also the anterior teeth to which it comes by several openings which exist in the upper part of the superior maxillary bone, and anastomoses with the branches of the facial, and also with those of the infra-orbital, artery.

k. The superior maxillary or alveolar artery {A. maxillaris superior, s. alveolaris) arises sometimes from one of the deep temporal or from the infra-orbital arterju It is larger than the preceding, goes a little downward and forward, turns on the upper maxillary bone, and sends off numerous large and small branches, one of which is termed the superior dental artery {E. dentalis superior ) into the teeth of the upper jaw. These branches nourish the dental capsules, the periosteum, the germ, the buccinator muscle, the zygonraticus major muscle, and anastomose with the branches of the facial and infra-orbital arteries.

l. The infra-orbital artery {A. infra-orbitalis) is generally smaller than the preceding, and arises near the bottom of the orbit. It soon engages itself in the infra-orbital foramen, and the infra-orbital canal, sends some branches into the orbit and the maxillary sinus, emerges by the infra-orbital foramen, behind the levator labii superioris, thus comes on the front of the face, and terminates in a great many ramuscules, some of which go to the muscles of the upper lip, while the others anastomose with the upper dental artery, the dorsal artery of the nose, the orbitar and the palatine artery.

Finally, at the upper end of the zygomatic fossa, the internal maxillary artery divides into an ascending and a descending branch, which goes inward.


246


DESCRIPTIVE ANATOMY.


m. The superior palatine artery ( A.palatina suprema , s. descendens, s. pterygo-palatina ) gives off, first, the superior or descending pharyngeal artery (A. pharyngœa suprema , s. descendens). This passes through the pterygo-palatine foramen, and expands in the pterygoid process of the bone, and the Eustachian tube and the upper part of the pharynx. Sometimes it arises from the internal maxillary artery by a distinct trunk. The superior palatine artery descends in the pterygoid canal and divides into several minuscules, which pass through different openings, to go to the soft parts of the palate. The trunk passes through the posterior palatine canal, comes on the palatine arch, rests directly on its lower face, describes a right angle to go forward, forming numerous curves, in its course gives off twigs to the mucous membrane of the palate and to the muciparous glands, and anastomoses forward with that of the opposite side, and sends its latter branches through the anterior palatine foramen into the nasal cavity, where they extend to the lower turbinated bone, communicating with the branches of the artery of the septum and of that of the dorsum of the nose which arise from the facial artery.

n. The last branch, the posterior nasal or sphenopalatine artery (A. nasalis posterior, s. splieno-palatina ), enters through the sphenopalatine hole into the posterior part of the nasal fossa, and divides into two branches, an external and an internal, and sometimes into three.

The internal branch, the posterior artery of the septum of the nose ( A . septi narimn posterior ), descends along the posterior pare of the septum of the nose, sends minuscules to the upper part of the pharynx, and penetrates into the posterior cellules of the ethmoid bone, and also into the upper turbinated bone.

The external branch descends along the outer edge of the posterior opening of the nasal fossae, and usually divides into two ramuscules, which go, the upper to the middle, and the lower to the lower turbinated bone. These ramuscules are distributed principally in the posterior part of the nasal fossa and of the maxillary sinus.

II. INTERNAL CAROTID ARTERY.

§ 1360. The internal carotid or anterior cerebral artery (A. carotis interna , s. cerebralis, s. cerebralis anterior , s. encephalica ) is usually smaller than the external, ascends behind it, before the internal jugular vein, on the outside of the pneu mo-gastric nerve, directly before the vertebral column, to the lower orifice of the carotid canal. It does not generally bend much, although it is sometimes very tortuous, and it is rarely straight.

It seldom gives off branches in this course. It rarely in fact furnishes one of the internal or posterior branches of the external carotid or of the occipital artery. The latter comes from them less frequently than the others. Upward it gives off sometimes a small branch, which goes to the palatine region and to the velum palati.


ANGEIOLOGY.


247


Immediately below its entrance into the carotid canal it is generally almost horizontal, or at least goes obliquely upward and forward. At the lower part of this canal it goes vertically upward. It afterwards goes forward at nearly a right angle, and becomes almost horizontal, although it ascends a little. After leaving the canal it resumes its primitive direction upward, but proeeeds at the same time forward and inward, and thus comes on the side of the sella turcica. At the posterior part of this excavation it curves a second time at a right angle, goes horizontally in the lateral carotid groove, going outward and a little downward. In this part of its course it accompanies the cavernous sinus of the dura mater, both being inclosed in the same portion of the dura mater, but separated by its proper membrane from the blood which it contains. At the anterior extremity of the lateral face of the sella turcica, below the anterior clinoid process, it describes a thud right angle, and goes upward, backward, and inward. In its course it gives off very trifling branches to the internal ear, to the dura mater, and to the third, fourth, fifth, and sixth pairs of nerves. Opposite the internal extremity of the upper orbitar fissure it divides into two branches, the continuation of the trunk which goes to the brain, and the ophthalmic artery.

Thus it changes its direction five times at least, and this arrangement retards the course of the blood much more, inasmuch as all the curves are sudden and do not occur on the same plane.

The internal carotid artery is intimately united by a very short cellular tissue to the canal through which it passes and which it almost entirely fills.


I. OPHTHALMIC ARTERY.

§ 1361. The ophthalmic artery (JL, ophthalmica ) is a very considerable branch, which exceeds in volume all those hitherto mentioned. It is always single. It leaves the skull through the optic foramen, usually on the outer and lower side, rarely at the upper part of the optic nerve, penetrates into the orbit, sends numerous branches to all parts of the eye, and also larger or smaller branches into the nasal fossæ and the face.

Having come into the cavity of the orbit, it soon ascends on the optic nerve, goes upward and inward, passes between this nerve and the rectus superior muscle of the eye, and thus arrives at the inner part of the orbit and goes forward to the internal angle of the eye.

Its branches vary surprisingly in respect to their origins, their number, and their volume. The principal are :

1st. Usually but not always an external posterior ciliary artery {A. ciliaris posterior), which arises from the outer side of the ophthalmic artery, goes forward along the optic nerve on its outer and lower side, and penetrates the sclerotica directly before the anterior extremity of this nerve.


248


DESCRIPTIVE ANATOMY.


2d. The lacrymal artery (A. lacrymalis) arises from the upper part of the ophthalmic artery, generally far backward and sometimes very far forward. It rarely arises from the middle meningeal artery, in which case it enters into the orbit, through the upper orbicular fissure, or through a special opening either in the malar bone or in the large wing of the sphenoid bone. It proceeds outwardly under the rectus superior muscle, to which it gives branches, and also to the rectus externus and to the levator palpebrarum muscles. It sometimes sends several through the malar bone into the temporal muscle, where they anastomose with those of the deep temporal artery. In some subjects one or several ciliary arteries arise from it. It then passes across, above or below the lacrymal gland, leaves the orbit at the external angle of the eye, anastomoses with the palpebral artery given off by the ophthalmic artery to form the palpebral arch, and terminates in the orbicularis palpebrarum muscle, the skin of the eyelids, and the tunica conjunctiva.

3d. The posterior upper ciliary artery (A. ciliaris posterior, superior ) is distributed in the same manner as the external, but gives off no branch after passing through the tunica sclerotica. Sometimes all the posterior ciliary arteries arise after the posterior ethmoidal artery ; but they always proceed very tortuously on the surface of the optic nerve, and after dividing into numerous branches, pass through the posterior part of the sclerotica to enter the eye, where they are distibuted in the manner stated in describing that organ.

4th. Next, a small inconstant branch arises and goes to the posterior part of the rectus superior muscle.

5th. The posterior or middle ethmoidal artery (A. ethmoidalis posterior , s. media) is also inconstant, and often arises from the lacrymal artery, from the anterior ethmoidal, or from the supra-orbitar artery.(l)

It gives first branches to the origin of the obliquus superior, rectus internus and externus muscles, then goes inward over the obliquus superior muscle, passes through the ethmoidal . or posterior internal orbital - foramen, comes into the nasal fossæ, and is distributed to the posterior ethmoidal cellules, the sphenoidal sinus, and the antrum Highmorianum ; it anastomoses with the branches of the posterior nasal or spheno-palatine artery and with the anterior ethmoidal artery, then reenters the skull through a small canal in the ethmoid bone, gives ramuscules to the periosteum which covers the anterior and central fossa of the base of the skull, and terminates by again passing into the nasal fossæ through the openings in the cribriform plate.

6th. The central artery of the retina (A. centralis retinae ), arises farther back, directly from the ophthalmic artery, or from the preceding, or from the lacrymal urtery, or from one of the two muscular branches ;

(1) But it is not always the smallest, as Bichat asserts ; we have remarked several times that it was one of the largest branches and much larger than the anterior.


AHGEIOI.OGY.


249


it goes into the optic nerve, proceeds forward along ils axis, and distributes itself to the retina, as we shall meniion in describing the eye.

7th. The inferior muscular artery (A. muscularis inferior ), is a considerable and rather constant branch, which sometimes gives off the central artery of the retina and one or more of the ciliary arteries, goes inward, sends branches to the rectus interims and inferior muscles of the eye, and penetrates even into the nasal fossæ.

8th. The superior muscular or supra-orbitar artery {A, muscularis superior , s. supra-orbitaria) is less constant than the preceding, but it comes from the lachrymal less frequently than from the ophthalmic artery. It proceeds forward directly below the orbitar plate, leaves the orbit through the supra-orbitar foramen, gives off branches to the frontal bone, to its periosteum, to the supraciliaris and orbicularis palpebrarum muscles, and to the skin of the forehead, and anastomoses with the other branches of the ophthalmic and with the temporal artery.

The anterior ciliary arteries (A. ciliares anticÅ“ ) arise from this branch and from the preceding ; they divide into fewer branches than the posterior, and enter the sclerotica much farther forward than the latter, near the transparent cornea.

The branches we have described generally arise near the floor of the orbit, not far from each other ; hence why they are generally long. After giving them off, the ophthalmic artery is usually smaller and proceeds along the- internal wall of the orbit, describing numerous curves. Towards the anterior opening of the orbitar cavity it gives off,

9th. The anterior ethmoidal artery (A. elhmoidalis anterior), which goes directly inward, passing over the obiiquus superior muscle, and penetrates through the ethmoidal or anterior internal orbitar foramen into the nasal cavity, where it is distributed to the anterior ethmoidal cells and the frontal sinuses, and anastomoses with the other nasal arteries. It also sends off branches to the anterior region of the dura mater.

The ophthalmic artery now proceeds a short distance within the orbit, afterwards leaves this cavity at the inner angle of the eye, and terminates in giving origin to,

10th. The paljiebral arteries (A. palpébrales]. These arise sometimes by a common trunk ( palpebralis communis) and sometimes separately, the superior a little before the inferior, and go outwardly. They are distributed partly to the conjunctiva, partly and particularly to the eyelids, in which they disappear between the skin and the orbicularis muscle. They divide there principally into two branches, one of which proceeds near the edge ( ramus marginalis) , while the other goes obliquely outward along the base of the eyelid.

The superior palpebral artery anastomoses in this place with the lachrymal, the superciliary branch of the frontal, and even some branches of the anterior temporal artery. It also forms a single or double superior palpebral arch ( arcus tarseus superior), which communicate with each other by numerous ramuscules, and thus form a net-work.

Vol. II 32


250


DESCRIPTIVE ANATOMY.


The inferior palpebral arch ( arcus larseus inferior) is produced in the same manner, by the anastomosis of the inferior palpebral with the infra-orbitar, the lachrymal and the nasal arteries.

All the parts of the eyelids are abundantly provided with vessels by these arterial branches.

11th. The frontal artery (A. frontalis ), which also ascends soon after arising, usually divides immediately into three branches, the supraciliary artery ( A, supraciliaris ), the superficial or subcutaneous frontal artery (A. frontalis subcutanea), and the deep frontal artery (A. frontalis profunda) . By this division it is distributed, 1st, to the upper part of the orbicularis palpebrarum and corrugator supercilii muscles ; 2d, to the frontalis muscle and to the skin of the forehead ; 3d, to the frontal sinus. It extends to the coronal suture and to the temporal region, where it anastomoses with the branches of the external temporal artery; it also communicates in other parts with those of the supra-orbitar and lachrymal arteries.

12th. The nasal artery {A. nasalis) varies much in volume. Sometimes it is a very small branch, terminating at the root of the nose ; sometimes it forms the continuation of the trunk of the ophthalmic artery, descends very low, contributes with the lateral nasal branch of the facial artery to produce the dorsal artery of the nose, extends to the end of the nose, proceeding on the side of this organ, always anastomoses with the inferior palpebral and the facial artery, and gives ramuscules to the integuments and to the nasal bones, to the frontalis muscle, to the internal part of the orbicularis palpebrarum, to the muscles of the nose, and even to the pituitary membrane.


II. CEREDRAL ARTERIES.

§ 1362. After giving off the ophthalmic artery, the internal carotid artery is distributed entirely to the cerebrum, particularly to its anterior portion, the posterior being supplied with blood from the vertebral artery. It properly deserves then to be called, from this point, the anterior cerebral artery (A. cerebralis anterior).

<§ 1363. It gives off, first, small ramuscules, which go inward, and are designed for the posterior part of the optic nerve, for the infundibulum, for the pituitary gland, and for the third ventricle.

§ 1364. It then gives off four branches ; these are the communicating artery, the choroid artery, the anterior cerebral artery, and the artery of the corpus callosum. The first two generally arise directly after each other ; and the carotid artery bifurcates farther on to give rise to the last two. Sometimes, but more rarely, three or all of these branches arise from the same point.

§ 1365. The first, or the posterior communicating artery (A. communicans posterior), goes backward and inward. It approaches that of the opposite side, opens into the posterior cerebral, which comes from the vertebral, artery, or if we prefer it anastomoses with a branch analogous to it, which it meets.


ANGEIÜLÙGY.


251


This anastomosis gives rise to the posterior part of the circle oj Willis ( circulus Willissii).

The size of this communicating artery varies extremely. It is generally considerable, and only about one half smaller than one of the succeeding branches, into which the internal carotid artery divides. It is sometimes however very small ; in this case the anastomosis between the internal carotid and the vertebral artery, frequently but not always takes place by means of another and larger branch of the anterior cerebral artery, which opens more outward into the posterior. The communicating artery is sometimes larger on one side than on the other.

Sometimes this artery is a branch of the anterior cerebral.(l) It arises more rarely not from this but directly from the basilar artery, when the posterior cerebral artery does not come from it. and it is given off by the internal carotid.

But the anastomosis almost always exists ; and it is constantly simple or at most double, on each side, when it occurs by considerable branches, although we find others which are accessory and smaller in the cerebral peduncles.

We consider its total absence as one of the rarest anomalies. We have never yet seen it, and Barclay alone mentions one case where the injection penetrated neither from the carotid into the vertebral artery, nor from the vertebral into the carotid.(2)

Several vessels arise from the communicating artery and go to the pia-mater or to the floor of the third ventricle, to the mamillary eminences, to the posterior part of the optic nerves, to the thalami optici, to the cerebral peduncles, to the inner face of the anterior part of the large cerebral lobe, and to the choroid plexuses.

§ 1366. b. Above the communicating artery, the internal carotid always gives off a special branch, the choroid artery (A. ckoroidta) which also arises from its posterior part. (3) This artery goes a little backward and outward, along the posterior edge of the origin of the optic nerve, ascends above the upper part of the cerebral peduncle, and expands partly in the pia-mater of the anterior part of the posterior


(1) This anomaly, however, is proportionally very rare. Portal then estimates incorrectly, the relation between the rule and the exception, in saying' that the internal carotid artery usually divides into two branches, the smaller of which is the artery of the corpus callosum, the larger the anterior lobate artery; the latter givingoffthe communicating artery, which sometimes arises directly from the internal carotid. Hilderbrandt seems to think that the two cases are equally frequent, which is just as false.

(2) hoc. cit., p. 47.

(3) We have always found this branch very constant, although several anatomists particularly Mayer, Murray, Portal, Hilderbrandt, and SÅ“mmerring, do not mention it. Haller states (le. anat., vol. vii. p. 5) that it sometimes exists. Sabatier, Boyer, and Bichat assert that is constant , which agrees with our remark. But Bichat errs in saying thatthe choroid is always smaller than the communicating artery. This case frequently occurs, since, as we have observed, the communicating artery is usually large ; but we have often found, when this was small, that the choroid artery was as large or even larger than it.


DESCRIPTIVE ANATOMY.


252

cerebral lobe anil of the thalami optici, and partly also penetrates through the anterior opening of the lateral ventricle, into this cavity, where its ramifications expand in the choroid plexus.

§ 1367. The internal carotid now divides, at a very obtuse angle and at the anterior extremity of the fissure of Sylvius, into two unequal branches ; these are the artery of the corpus callosum and the anterior cerebral artery.

§ 136S. The artery of the corpus callosum ( A . callosa, s. corporis callosi, s. anterior cerebrica , s. anterior hemisphÅ“ri, s. mesolobica ) is always smaller than the posterior branch. It goes forward and inward, directly before the union of the optic nerves, proceeds to meet that of the opposite side, towards which it converges very much, and after giving off superiorly generally several ramuscules for the posterior extremity of the anterior lobe, for the olfactory and for the optic nerves, it anastomoses with it between the posterior extremities of the first two lobes by the anterior communicating artery (A. anterior communicans , s. anostomotica). This branch is generally very short ; sometimes however, it is three or four lines long ; it is generally much larger in the former case and often very narrow in the second. Its direction is always transverse. Sometimes it is entirely double; and we not unfreqüently find it, double in one half its extent.(l) It gives off, particularly when longer than usual, ramuscules, which go upward and backward, into the septum lucidum, the fornix, and the corpus callosum.

The trunk also generally sends off one or more small branches which proceed forward and outward to the inner part of the inferior face of the anterior lobe of the cerebrum. After this, it is situated directly near that of the opposite side, turns on the anterior extremity of the corpus callosum, ascends to the inner face of the cerebral hemispheres, and divides into several branches, the anterior of which enter into the circumvolutions of this internal face, while the posterior proceed on the corpus callosum, as far as its posterior extremity, where they begin to change their direction and to go upward. All these branches extend to the upper face of the cerebrum and anastomose with those of the succeeding artery, and with those of the posterior cerebral artery, given off by the vertebral artery.

Besides these large branches, into which the artery of the corpus callosum divides above, it also gives off, from its lower and concave part, numerous smaller branches, whtch distribute themselves in the corpus callosum.

Rarely, a large posterior branch is detached on both sides at the place where the two arteries of the corpus callosum meet, and the anterior anastomosing branch becomes the single trunk of the anterior part of the artery of the corpus callosum, which shortly divides into two large branches, a right and a left, or the two arteries arise


(1) Bichat is incorrect in stating that this arrangement is very rare.


ANGEIOLOGY.


253


from a common trunk, and do not give oft a branch posteriorly. This arrangement is remarkable because of the analogy it establishes with the union of the two vertebral arteries into one, the basilar, which is situated on the median line.

§ 1369. The anterior or more properly the middle cerebral artery (A. cerebri anterior, s. media , s. hemisphcerica media, s.fossÅ“ Sylvii, s. sylviana), the last and the most posterior branch of the internal carotid, is always much larger than the preceding. Soon after its origin it goes outward, and only a little inward ; it enters the fissure of Sylvius, gives off, at its upper and posterior part, numerous, generally small, ramuscules, some of which penetrate into the anterior extremity of the posterior lobe, others into the posterior extremity of the anterior lobe, and afterward divides generally about half an inch from its origin into two, three, or four large branches. The largest of the latter are turned backward, soon bifurcate, and proceed, closely against each other, into the bottom of the fissure of Sylvius, where they go upward and backward. The anterior attain the posterior and external part of the anterior lobe, and the posterior the anterior central part of the posterior lobe, gliding in the circumvolutions of the posterior face of the first and the anterior face of-the second, but penetrating mostly into their substance, through their outer face, and thus extend to the upper edges of the hemispheres, where they anastomose with the ascending branches of the anterior and posterior cerebral arteries.

§ 1370. The anterior and middle cerebral arteries are not always arranged symmetrically. The two large middle arteries not unfrequently arise (as Haller states and as we have verified) from the right carotid only, and the anterior, which is smaller, from the left carotid, an arrangement which deserves to be remarked as indicating the predominance of the right side over the left.

Sometimes also only the left anterior artery comes from the internal carotid of the same side, and the other three come from the right. We have seen this anomaly in several subjects.

If we add the union of the arteries of the corpus callosum at their origin, which we mentioned above, we here find a remarkable repetition of several of the varieties to which the origins of the trunks coming from the arch of the aorta are subject.


ARTICLE FOURTH.

ARTERIES OF THE UPPER EXTREMITIES.

§ 1371. The arteries of the upper extremities, for which we cannot find a better term than that of the brachial arteries(l) ( J1 . brachiales),

(1) This term is generally applied only to that portion of the artery which corresponds to the arm, and which might more properly be termed the humeral artery.


254


DESCRIPTIVE ANATOMY.


arise on each side by a single trunk, generally called the subclavian arteiy (A. subclavia).


I. SUBCLAVIAN ARTERY.

§ 1372. The two subclavian arteries {A. subclavia) arise from the ascending aorta, and extend to the scaleni muscles. They differ in their mode of origin ; for the left subclavian artery arises directly from the arch of the aorta, while the right proceeds indirectly from it, as it is the external branch of the trunk of the innominata ( truncus communis innominatas), which bifurcates and gives origin to it and to the right primitive carotid.

This at least is the most common arrangement. Sometimes, but rarely, the subclavian arteries arise directly from the arch of the aorta. We may there find two principal differences. Sometimes in fact the trunk of the innominata gives off the right subclavian and the carotid, the subclavian artery arising on the right, outside of the carotid, which is the least but also the rarest anomaly. Sometimes the right subclavian artery arises more to the left, until it is the extreme left trunk of those which arise from the arch of the aorta, below the left subclavian artery, and goes to the right, towards the corresponding limb, passing behind the other trunks, rarely directly, more frequently between the trachea and the esophagus, and still more frequently between the esophagus and the vertebral column.

§ 1373. The first branches of the subclavian artery are never constant. They often and in fact almost always arise from its upper extremity, directly before its passage between the scaleni muscles. But sometimes the artery gives off much sooner, and even near its origin, considerable branches, which go to the thymus gland, to the upper part of the pericardium, also to the trachea, to the bronchiæ, and to the esophagus (A. thymicÅ“, pericardiacee superior , anterior et posterior , broncliicÅ“, Å“sophagece, broncho-Å“sophagece), but they rarely or never belong to these parts alone, although they distribute branches to all. Even when these branches arise from the subclavian artery (which occurs on the left side more frequently than on the right, because it descends deeper) its course is no shorter, but it gives off no branch until just before passing between the scaleni muscles. Here, however, several large branches arise from it. These may be distinguished generally speaking into the upper or posterior and the lower or anterior branches ; and they vary much, for, 1st, the same twigs do not always arise from the same branches, so that the latter are not always of the same caliber ; 2d, small branches sometimes arise from the subclavian artery, by a common trunk, whence their number varies : 3d, they do not always emerge from the same point of the subclavian artery, the inferior arising sometimes farther forward, and the superior farther backward than usual.


ANGEIOLOGY.


255


A. UPPER POSTERIOR BRANCHES.

§ 1374. The most constant of the upper and posterior branches are two, the vertebral artery and the inferior thyroid artery.

I, VERTEBRAL ARTERY.

§ 1375. The vertebral artery (v3. vertebralis ) is generally the first and largest of the two upper branches of the subclavian artery. Shortly after arising, it enters the arterial canal of the cervical vertebrae, and goes from below upward. This artery shows a great disposition to change its origin, and to arise directly from the arch of the aorta. We shall remark, 1st, that this anomaly, however common it may be, is seldom seen on the right side (at least to our knowledge), and that it rests always on the left ;( 1 ) 2d, that when it occurs, the vertebral artery is almost always inserted between the left carotid and the left subclavian arteries. If this branch arises directly from the arch of the aorta more frequently than the others, it may be attributed, we think, to the following facts : 1st, in the normal state it is the first branch of of the subclavian artery ; 2d, the vertebral vein normally empties itself into the common trunk of the subclavian and jugular veins. The other fact, that the anomaly appears almost entirely on the left side, seems to us to depend on this, that the division of the trunk into branches characterizes the left side of the ascending aorta even in the normal state, since the subclavian arteries there arise separately, and are not blended in a single trunk, as on the right side. The greater length of the left trunk of the innominata vein may contribute to it, since this anomaly should be considered, as we have remarked, an imitation of the arrangement of the venous system. Finally, the situation of this artery between the left carotid and the left subclavian arteries probably depends on its arising, in the normal state, from the internal and posterior side of the subclavian artery.

We sometimes but rarely find on the right side a similar anomaly where the vertebral artery arises from the bifurcation of the trunk of the innominata ; this is still more curious, because in comparing this arrangement with that on the left side we have a new proof that the anomaly does not destroy in the two sides the character of the normal type.

We know of only one case where the right vertebral artery arose from the arch of the aorta ; but that of the left side also presented the same anomaly.

(1) This might be easily proved by numerous quotations. Of all the authors who mention this variety Mayer is the only one who asserts the contrary; for, without speaking of the left vertebral artery, he asserts only that the right sometimes arises directly from the arch of the aorta. This assertion is so cont radictory to observation that it can be explained only by considering it as a typographical error.


256


DESCRIPTIVE ANATOMY.


A second anomaly of the vertebral artery consists in its division into several trunks. Sometimes then one of the trunks arises directly from the arch of the aorta ; the other, which is generally smaller, from its usual place ;(1) or both come from the subclavian artery, at. a greater or less distance from each other. Perhaps the first arrangement also is found only on the left side ; at least in a specimen before us, and where the anomaly exists on the right, the two vertebral arteries are branches of the subclavian artery. In both cases one of the trunks, particularly the largest, enters the vertebral canal higher than usual. Sometimes it unites with the other, which enters at the normal place ; sometimes it unites with it before entering this canal ; sometimes, finally, the smallest branch extends into the veitebral canal after passing over one or more vertebral foramina.

Even when the vertebral artery is normal in respect to its origin, it enters the vertebral canal at several different points. Its proper place is the vertebral foramen of the sixth cervical vertebra. (2) In extremely rare cases this artery enters through the vertebral foramen of the seventh cervical vertebra.(3) Even when it arises lower than usual, from the arch of the aorta it however enters into the hole of the sixth cervical vertebra, and we have frequently seen it in this case not enter the vertebral canal until it reaches the fifth vertebra.

More frequently, although not very often, the vertebral artery, even if not double, enters through the vertebral foramen of the fifth, fourth, third, or even the second cervical vertebra. We know of no case in which it has been found entirely out of the vertebral canal, and we have never known it to leave this channel lower than the upper vertebra, or to leave a vertebra, pass through a certain extent on the anterior face of the transverse processes, and enter again into the vertebral canal.

Finally, the vertebral artery of one side is very frequently much larger than that of the other, although according to our observations the sides of the body have no effect on this disproportion.

This anomaly confirms the general rule that the synonymous arteries which go to the single organs on the median line of the body often differ in volume and enlarge on one side at the expense of the other.

(1) Henkel, Anmerkungen von weidernatürlichen Geburten , zweite Sammlung, p. 10, 11. — Huber, Dc arcus aortce ramis ; in the Act. Helv., vol. viii. p. 68-102.

(2) We have always observed this, except in a very few instances. Haller (/c. anat.fasc. ii., e.vplic. icon. 2, art. thyr. infer., not. c) and Scemmerring (p. 177) are then correct in saying that this arrangement is normal. Mayer mistakes in saying (p. 110) that there is for the vertebral artery a special opening, through which it enters into the vertebral canal, sometimes in the seventh and sometimes only in the sixth cervical vertebra. This opening always exists except in a very few instances in the seventh cervical vertebra ; but the vertebral artery rarely or never passes through it and always enters through the sixth. What Mayer considers the normal state is a rare anomaly, and vice versa. Monro ( Outlines , <f-c., vol. iii, p. 301) is also mistaken in thinking that the artery enters through the seventh cervical vertebra as often as it does through (he sixth.

(3) Bichat (p. 193) is correct in saying that it sometimes but rarely enters through a similar foramen of the seventh cervical vertebra. This arrangement is rare, as Haller, Murray, and Scemmerring have not spoken of it, although they mention the next.


ANGEIOLOGY.


257


§ 1376. The vertebral artery ascends in an almost straight line to the second cervical vertebra ; but at this point it becomes tortuous and describes several curves, four of which are very remarkable. First, it penetrates into that part of the canal which belongs to the transverse process of the second vertebra, forming a right angle, assuming an entirely horizontal direction, and going transversely outward ; then passing through this opening, it describes another right, acute, or obtuse angle, resumes its first direction, and becomes perpendicular again at the upper cervical vertebra. When it has passed through the vertebral foramen it inclines again at a right angle, resumes a second time a horizontal direction, and goes backward and inward, turning around on the articular process of the first Cervical vertebra, along its posterior groove. From the posterior extremity of the articular process it goes gradually and at an obtuse angle inward and upward, and soon enters the cranium, passing through the dura mater and the large occipital foramen directly above the occipital condyle. Having entered the skull, it is situated first on the side, then on the lower face of the medulla oblongata, and ascends forward and inward on the basilar process of the occipital bone. There the two arteries approach each other, and after passing usually more than an inch within the cavity of the skull, they unite at an acute angle, either a short distance behind the posterior edge of the pons Varolii, or on this edge, or even in its centre. They always, as far as we know, unite and give origin to a single trunk, the basilar artery (A. basilaris ), which is much smaller than the two branches which produce it. In size it nearly equals the internal carotid artery after it gives off the ophthalmic artery. It proceeds forward to the centre of the lower face of the pons Varolii, and divides a£ its anterior extremity into two large branches, a right and a left.

§ 1377. In this course the vertebral artery generally gives off no branches, or at least but small and inconstant ones. These- branches are' distributed to the anterior deep muscles of the neck. In this respect the vertebral artery resembles the internal carotid.

§ 1378. From the portion within the vertebral canal several small branches pass forward, outward, and backward, generally between every two vertebrae, and go to the vertebrae, to the intertransversarii, to the multifid us spinæ, to the anterior deep muscles of the neck, and to the small muscles of the head.

Internal branches, which are also very small, pass through the intervertebral foramina, either alone or attended with small arterial twigs from the other branches of the subclavian artery, penetrate the vertebral canal and are distributed partly to the nerves, others to the anterior and posterior sides of the dura mater and to the pia mater of the spinal marrow. They anastomose with those of the opposite side and with the anterior and posterior spinal arteries.

Considerable branches arise- from that part of the vertebral artdry between the first and the second cervical vertebrae, and also between tire Vol. II m


DE S C Rir T I VE A N A T 051 V


2o8

latter and the occipital bone. Some go outward, are expanded in the transversales colli and the coinplexus minor muscles, and anastomose with the branches of the ascending cervical artery, and sometimes entirely replace it. The others proceed backward and outward and are distributed in the posterior and lateral small muscles of the head. Some go inward and anastomose with the synonymous branches of the other side. Finally, man}' enter the tissue of the dura mater.

§ 1379. The largest branches arise from that part of the vertebral artery within the skull. From the difference of caliber between the branches which it sends out of the cavity of the skull, this part is frequently much larger on one side than on the other, although both have primarily the same diameter at their origin and although the side of the body has no necessary influence upon this difference.

The branches which arise before the two vertebral arteries unite are the anterior spinal artery, the posterior spinal artery, and the inferior artery of the cerebellum.

§ 1380. The posterior spinal artery (A. spinalis posterior) is the smallest, and often comes from the inferior artery of the cerebellum. It arises the lowest and from the outside of the vertebral artery, goes inward on the posterior face of the spinal marrow, and descends on each side along the posterior spinal groove to the end of the spinal marrow. The two arteries are very tortuous and are parallel to each other. They are always enlarged by the accessory ramuscles of the vertebral, the deep cervical, and the intercostal arteries which pass through the intervertebral foramina, and anastomose by numerous transverse branches, which generally correspond to the intervertebral spaces ; so that each portion of the spinal marrow between two vertebrae has its special vascular circle, even as the four cerebral arteries form one by their anastomoses. •

§ 1381. The inferior artery of the cerebellum (,R. inferior cerebelli) a-lso arises from the outer side of the vertebral artery and is usually double on both sides.

One, the posterior inferior artery of the cerebellum, arises farther backward, and goes backward, upward, and inward, proceeds on the lateral parts of the medulla oblongata, distributes its branches to the tela choroidea of the cerebellum and to the floor of the fourth ventricle, and ascends between its two hemispheres to its vermiform eminence and to the inner face of its two hemispheres. This branch often exists on one side only, and then it is observed particularly when the inferior artery of the cerebellum arises very far forward.

The anterior inferior artery of the cerebellum sometimes arises at the origin, sometimes also at the extremity of that portion of the vertebral artery within the skull. In some subjects, particularly when the vertebral arteries unite early, it comes from the basilar artery. These varieties are observed even on both sides of the body at once. The anterior inferior artery of the cerebellum not only frequently exists alone but it is generally much larger than the posterior. It is some

ANGEIOLOGY


2Ô9


times much smaller on one side than on the other. It proceeds very tortuously outward and backward to the lower face of the cerebellum., where impasses on the grooves which it crosses and divides into branches, some of which go backward and others forward. These branches also cross the direction of the grooves of the cerebellum ; the small ramifications alone become parallel and finally penetrate into them.

§ 1382. The anterior spinal artery (A. spinalis anterior) generally commences a short distance from the lower edge of the pons Varolii, even when the two vertebral arteries unite much higher than usual. It arises from the internal part of the trunk and soon unites with that of the opposite side in a single trunk on the median line, which descends along the anterior groove of the spinal marrow. Generally, particularly when the two vertebral arteries unite higher than usual, we find a small anterior and superior spinal artery, which is sometimes single and arises from the top of the angle of union, and sometimes double, which blends likewise with that of the opposite side, and which, proceeding also from above downward, soon anastomoses with the lower. The single trunk of the latter, which corresponds to the median line, is often divided in its course and thus forms considerable islands. Its upper part receives also from all or most of the intervertebral foramina considerable branches, which are given off by the vertebral or the other cervical arteries to the anterior face of the spinal marrow and anastomose with it. During its course, which is very tortuous, it sends off on each side numerous branches to the spinal marrow.

II. BASILAR ARTERY.

§ 1383. The basilar artery (A. basilaris, s. meso-ccp'halica) is comstant, and arises, proceeds, and varies in the manner mentioned above. We however sometimes remark in its arrangement a tendency to a want of union or to the separation of the vertebral arteries, since it forms islands, especially at its posterior part. This artery is however the only one in which we have observed this arrangement. It very soon divides into two parts, which almost immediately unite. We consider this anomaly as very rare, not only because we have never seen it but twice, but because it is not mentioned by the most correct angeiologists.(l) It is curious not only as an anomaly, but because it increases the analogy between the basilar and the anterior spinal arteries, which are already so similar. It is not unimportant to say, that in the two subjects which presented this unusual arrangement the anterior communicating artery of the two internal carotids presented analogous

(1) An arrangement has been figured by Heuermann ( Physiologic , vol. ii. tab. 8) where the two vertebral arteries were connected behind their union by a large trans'verse branch, to give rise to the basilar artery, which seems to have some relation with this anomaly ; but more probably it consisted only in the union of the anteriorspinal arteries, since the two 'vertebral arteries are not v-ct united behind this branch.


260


DESCRIPTIVE ANATOMY


divisions. In the latter however this anomaly is much more common than in the'basilar artery.

From both sides of the basilar artery numerous branches arise, generally at right but sometimes at angles slightly acute, backward, which vary much in number and volume and do not correspond perfectly on both sides. The smallest enter into the pons Varolii and the nerves which come from it ; the largest, even when the usual inferior arteries of the cerebellum do not exist, proceed even to the lower face of the cerebellum.

Some branches, the internal auditory arteries (A. auditives internez ), enter into the internal auditory foramen, expand in the labyrinth, and anastomose with the branches of the internal and of the external carotid arteries which enter into this organ.

§ 1384. At its anterior extremity, in the middle of the anterior edge of the pons Varolii, the basilar artery usually divides into four branches, two on each side, the superior artery of the cerebellum and the posterior cerebral artery.

§ 1385. The superior artery of the cerebellum (A. cerebelli superior) which is almost as large as the inferior, is rarely deficient on one side, in which case it is replaced by a branch of the following. It is more frequently double ; and then the vertebral artery divides into five branches, of which the two superior arteries of the cerebellum are situated very near each other : sometimes but much more rarely, it arises some lines behind the anterior extremity of the vertebral artery. It goes transversely outward and upward, directly behind the anterior edge of the pons Varolii, then proceeds a little backward, turns upon the pons Varolii to arrive at the anterior edge of the cerebellum., and divides into superficial and deep branches. The first proceed backward on the ridge of the cerebellum to its posterior edge, where they anastomose with the branches of the inferior artery of the cerebellum ; the others penetrate upward into the anterior lobes.

§ 1386. The two anterior branches, the posterior or deep cerebral arteries, Lobaires postérieures du cerveau , Ch. {A. cerebri posteriores , s. profundœ), are much larger than the superior arteries of the cerebellum. They arrive at an acute angle, separate much from each other, and go forward and outward. They usually give off near their origin and at their upper and external part several branches, some of which are considerable and go to the cerebral peduncles, to the thalami optici, to the tubercula quadrigemina, and to the valve of Vieussens. After proceeding a short distance they divide into two branches, the communicating artery and the continuation of the trunk.

The communicating artery is situated inward, and is smaller than the other. Its direction is outward and forward and it proceeds to meet the anastomosing branch of the internal carotid artery, with which it unites.

The continuation of the trunk of the posterior cerebral artery, which fa usually the smallest of the 4hree proper cérébral arteries, sometimes


ANGELO LOG"?.


261


aiises from the internal carotid artery, previous to its bifurcation, and sometimes also from the union of the anastomosing branches given off by the internal carotid and the vertebral arteries. It goes outward and upward, before the third pair of the cerebral nerves, and turns on the cerebral peduncle, to the lower face of which it gives some ramuscules, which thus arrive at the thalami optici and the tubercula quadrigemina, penetrate into the third ventricle, and are distributed principally to the choroid plexus. Finally, it goes on one side to the posterior part of the cerebrum and of the corpus callosum, and also to the thalami optici on the other, particularly to the lower face of the cerebral hemispheres. It anastomoses very frequently with the anterior or central arteries and with the arteries of the corpus callosum, which arise from the internal carotid artery.

§ 1387. The peculiarities presented by the arteries of the brain have been described before or will be mentioned when we speak of the encephalon.


II. INFERIOR THYROID ARTEEY.

§ 1388. The inferior thyroid artery (Jl. thyroidea inferior, s. sacro thyroidea, Barclay ) arises from the subclavian artery, more outward and forward than the vertebral artery, from which however it is not always the same distance. It most generally gives off the inferior thyroid branch and several twigs, which go to the muscles and to the slan of the neck, the back, and the shoulder.

This artery is large, particularly in the child, where it is equal to the subclavian or even the carotid artery. Its size however varies much, because that one or more branches which it commonly furnishes frequently arise from other trunks, but the arteries which generally come directly from the subclavian artery are rarely given off by it. This is true for instance of the internal mammary artery, and the former is true in regard to the branches which go to the muscles of the neck, shoulder, and back. Sometimes it goes only to the thyroid gland. In other cases it is uncommonly large, because it gives off not only the usual branches but also the internal mammary artery. In rare cases, on the contrary, it does not deserve its name, because it gives branches only to the muscles and the inferior thyroid arises from the common carotid artery, or does not exist as a separate vessel, but is blended with the superior thyroid artery. This anomaly is curious, as it is a repetition of the normal formation of most mammalia.

Another and somewhat similar anomaly is when the inferior thyroid artery is uncommonly small, either on one or both sides, and one or both of the superior thyroid arteries are larger in the same proportion, or finally when beside the two common thyroid arteries, there is also a third (Jl. thyroidea imu , s. Neubaueri), which arises lower down either from the arch of the aorta on the right of the left carotid or from the common trunk of the carotid and the Subclavian artery, when the


262


IJES'CRirïXVE ANATOMY


anomaly occurs on the right side, or from the common trunk of tin carotids of one side only, df finally from both sides at once, sometimes higher and sometimes lower.

We must also mention here the rare anomaly where the inferior thyroid artery is totally deficient on one side, while on the other, in the usual place, particularly on the right, instead of the two inferior thyroid arteries, we have a common trunk, ( 1 ) which arises sometimes from the aorta and sometimes from its usual place. We have twice observed a case resembling this, where the inferior thyroid artery arose from the arch of the aorta, between the trunk of the innominata and the left carotid arteries.


III. SUPERIOR SCAPULAR ARTERY.

§ 1389. In most cases the inferior thyroid artery, immediately after arising, gives off the superior scapular artery (R. transversus scapulÅ“, s. scapularis transversa, s. scapularis superior , s. cervicalis superficialis ), which however sometimes arises from the subclavian artery, sometimes singly, and sometimes by a common trunk with the following. It goes transversely backward and outward behind, and a little above the clavicle between the scalenus anticus and the scalenus médius ; gives branches to the sterno-thyroideus,the sterno-hyoideus, the omohyoideus, the scaleni, the trapezius, and the supraspinatus muscles ; passes between the spine and the glenoid cavity of the scapula, and enters the infraspinalis fossa. There it divides into several branches, the smallest of which usually pass through the semicircular notch to the anterior face of the scapula and to the subscapularis muscle, while the largest are distributed on the posterior face of this bone, to which it gives one or more nutritious twigs, and terminates in the infraspinatus muscle. Another branch arises from this point and goes forward between the proper and common ligaments of the scapula, distributes itself in the articular capsule of the shoulder and to the upper and anterior jtart of the deltoides muscle, and anastomoses by several large branches with the anterior circumflex artery of the arm and with the great thoracic artery.

IV. TRANSVERSE CERVICAL ARTERY.

§ 1390. The transverse cervical artery (Jl. cervicalis superficialis, s. cervicalis transversa, s. colli transversa ), which is generally as large as the preceding, arises from the inferior thyroid artery, a little higher and at some distance from it outwardly ; it often arises directly from the subclavian artery. It goes transversely outward and backward. It is situated at first on the side of and a little behind the superior capsular artery, and it gives off in this course branches to the scaleni muscles.


(1) Burns, loc. cit., p. 331.


ANGEIOLGGV.


2j63


and divides into two large branches on a level with the upper edge of the shoulder. The ascending branch becomes the principal branch of the trapezius and also sends some ramuscales to the levator scapulae muscle ; the other descends along the base of the scapula, between the rhomboidei and the serratus magnus muscles, in which course it gives off twigs to these muscles and also to the lower part of the trapezius muscle.

§ 1391. A little higher, one or more small branches ( R . thoracici ) arise very constantly from the inside of the inferior thyroid artery ; these go upward and inward to the lower part of the longus colli muscle, penetrate also the spinal canal through the intervertebral foramina, but go particularly to the trachea and to the esophagus. The latter are termed the bronchial and the esophagceal arteries (A. branchiales, Å“ sophageÅ“, s. broncho-Å“sophageÅ“) .

§ 1392. After passing through rather a long course upward without giving off any branch, the inferior thyroid artery divides into two branches, the ascending cervical artery, which is generally much smaller and goes upward and outward, and the thyroid artery, which may be considered as the proper continuation of the trunk.

V. ASCENDING CERVICAL ARTETE.

§ 1393. The ascending cervical or the superior dorsal artery (A. cervicalis ascendens, s. dorsalis supremo) is a very constant branch of the inferior thyroid artery and sometimes but rarely arises from the subclavian artery ; this happens particularly when the branches already described arise separately from the proper thyroid artery. Sometimes also it arises from the internal mammary artery. It ascends along the transverse processes of the cervical vertebrae, between the longus colli and the scaleni muscles. In its course it gives off backward, outward, and upward several considerable branches, which are distributed in the upper part of the trapezius, the levator scapulae; the serratus magnus, the se,rratus posticus, the scaleni, and the splenii muscles, and the skin of the neck : the trunk generally goes backward, below the transverse process of the third cervical vertebra, penetrates deeply between the transversalis colli and the complexus minor muscles, and having thus come upon the posterior face of the neck, it terminates in twe principal branches ; the smaller ascends behind the transverse processes of the cervical vertebrae, gives ramuscules to the complexus minor muscle and to the posterior small muscles of the head, anastomoses with the vertebral and occipital arteries, and finally penetrates into the spinal canal between the first and second cervical vertebrae, where it terminates in the dura mater. The other is larger and is the continuation of the trunk : it goes outward between the fasciculi of the complexus major muscle, and terminates in this muscle and in the digastrieus and the posterior muscles of the head .


204


OESCRIPTIVB ANATOMY.


§ 1394. The thyroid branch (R. thyroideus) sometimes arises singly from the subclavian artery, from the aorta, the innominata, or from the common carotid artery. It is sometimes entirely deficient in some subjects, but is generally the largest branch of the inferior thyroid artery. It is very tortuous and curves very much in ascending toward the thyroid gland. It usually passes behind, sometimes but rarely before, the primitive carotid, in order to arrive at this gland. Before reaching it, it divides into several branches, which enter this organ principally on its lower edge and lower face and anastomose with each other and with those of the superior thyroid artery.

The thyroid branch also gives in its course smaller ramuscules to the longus colli muscle, to the pharynx, and particularly to the larynx. The latter is termed the inferior laryngeal artery (Jl. lanjngea inferior).

VI. LOWEST THYROID ARTERY.

§ 1395. Besides the branch described (§ 1364), another branch called the lowest thyroid artery (Jl. thyroidea ima ) arises, sometimes from the primitive carotid or from the innominata, from the arch of the aorta or from the subclavian artery, by a trunk in common with that of the opposite side.

This anomaly occurs on the right side more frequently than on the left ;( 1 ) we have never observed it on the latter side, although we have frequently seen it on the other. In one case only, where the origin of the inferior thyroid artery was abnormal, it did not arise from the left side of the arch of the aorta, but from the right side, between the innominata and the left carotid artery ; thence it passed before the trachea to go to the left side of the thyroid gland, while the origin and direction of the right was normal. This anomaly then seems properly to belong to the right side, even as the similar anomaly of the vertebral artery appears exclusively on the left side.

Finally, whether this abnormal artery forms a part or the whole of the inferior thyroid artery, whether it arises from the innominata, or from the arch of the aorta, or deeply from the primitive carotid artery, it always passes on the anterior face of the trachea to go to the thyroid gland, into which it enters from below upward. It cannot then escape being wounded in the operation of laryngotomy.

(1) We have found it nine times on the right. Hubert (toe. cit., p. 84) has seen the lowest thyroid artery arise four times from the common trunk, three times on the right and only once on the left side. Neubauer has also seen the right coming from the aorta (in Erdmann, Descrip, art. thyr. imee, Jena, 1772). Ramsay (Account of an unusual conformation of some muscles and vessels, in the Edinb. Med. and Surg\ Journ., vol. viii. p. 281-283, tab. 1, fig. 2) has found it arising from the innominata trunk. Loder has twice seen it arising from the aorta, between the right carotid and the subclavian arteries : the innominata trunk did not exist in these two cases (De nonnullis arteriarum varieUdibus, Jena, 1781).


ÀNGEIOLOGY.


265


VII. DEEP CERVICAL ARTERY.

§ 1396. The deep cervical artery (A. cervicalis profunda) often forms a special trunk, which arises from the back side of the subclavian artery, a little more externally than the preceding, but frequently by a common trunk with the superior intercostal artery. It is rarely given off by the inferior thyroid or even by the vertebral artery ; in the latter case its origin is generally a little below that of the vertebral artery. It more rarely comes from the upper part of the latter, in which case it sometimes descends between the first cervical vertebra and the occipital bone, and is afterwards distributed as usual, but so that its lower branches are almost always supplied by the other branches of the subclavian artery.

It goes obliquely upward and outward, passes backward between the transverse processes of the sixth and seventh cervical vertebrae or the latter and the first dorsal vertebra. It ascends between the transversale colli, the spinalis colli, and the semispinalis dorsi muscles on one side, and the digastricus and the complexus muscles on the other. It also distributes branches to the scaleni, the complexus minor, the cervicalis descendens, the trapezius, the splenii, and the small posterior muscles of the head, and anastomoses, especially above, near the occipital foramen, with the branches of the vertebral and occipital arteries. It also sends ramuscules into the spinal canal through the intervertebral foramina, which anastomose there with the spinal arteries given off by the vertebral artery.

B. INFERIOR BRANCHES.

§ 1397. The inferior branches of the subclavian artery are the internal mammary artery and the superior intercostal artery.


I. INTERNAL MAMMARY ARTERY.


§ 1398. The internal mammary artery (A. mammaria interna , s. sternalis , s. substernalis) is much smaller than the vertebral and the inferior thyroid arteries. It arises ordinarily and very constantly by a -distinct trunk from the anterior or inferior side of the subclavian artery, nearly opposite the inferior thyroid artery. It however in some rare cases, one of which is now before us, arises by a common trunk with the latter, or on the right side from the innominata,( 1 ) or even from the arch of the aorta. (2)

It generally goes downward and inward, but sometimes also ascends a little before taking this direction, which it long preserves. It

(1) Neubauer, loc. cit., p. 33.

(2) Bcehmer, De quat. et quinq. aortæ ram.; in Haller, Collect, diss. anat.. vol. ii. p. 452.

Vol. II. 34


266


DESCRIPTIVE ANATOMY.


descends almost in a straight line to the posterior face of the anterior wall of the chest, on the costal cartilages between the intercostales and the triangularis sterni muscles, nearer its internal than its external extremity, consequently not far from the two edges of the sternum, which it also approaches a little below.

Besides several branches which go from its upper part to the lower part of the anterior muscles of the neck, it sometimes gives off a superior bronchial artery, the thymic, and a branch which is distributed to the pericardium and also to the anterior mediastinum. But its upper part constantly gives off a branch which accompanies the diaphragmatic nerve, called the superior diaphragmatic artery (A. diaphragmatica superior , s. pericardio-diaphragmatica). This branch sends ramuscules to the pericardium, to the internal wall of the mediastinum, and to the esophagus, and expands in the anterior and middle portion of the diaphragm, where it anastomoses with the inferior diaphragmatic artery.

In its course along the sternum the internal mammary artery gives off external and internal branches.

The external branches, the anterior intercostal arteries, {A. intercostales anteriores ), are usually larger and more numerous than the internal. Their number is not exactly the same in every part, but they equal in number the intercostal spaces, over which the internal mammary artery passes. They generally proceed along the lower, rarely along the upper edge of the ribs, and almost always in the latter case one intercostal space contains two of them. They go backward between the intercostales interni and extern! muscles, and anastomose with the intercostal arteries given off by the descending aorta and with the thoracic arteries which arise from the axillary artery.

One of these branches, the fifth, sixth, or seventh, has been called the musculo- diaphragmatic artery (A. musculo-phreniea ). It is usually very considerable, sometimes as large as the trunk, of which it seems even to be a continuation. It is distributed not only to the anterior part of the diaphragm but also it arrives at the upper part of the broad abdominal muscles, whence its name, where it anastomoses with the epigastric artery.

The internal branches, which are smaller and fewer than the preceding, go, some to the internal face of the sternum, others to the anterior face of the pericardium, and some, viz. the deepest, to the anterior part of the diaphragm ; finally, others leave the pectoral cavity through the intercostal spaces and are distributed in the upper part of the abdominal muscles.

The trunk of the internal mammary artery commonly divides into two principal branches of different sizes, an external and an internal. This bifurcation occurs sometimes higher and sometimes lower, and occasionally it is seen opposite the anterior extremity of the fifth rib, and sometimes only opposite the eighth.

The external branch goes obliquely outward, along the costal cartilages, above the intercostal spaces. It terminates by the lowest of the


ANGEIOLOGY.


267


anterior intercostal arteries and by small branches which enter the anterior edge of the diaphragm and the upper part of the broad abdominal muscles. It is also called the superior epigastric artery (Æ epigastric a superior).

The internal branch proceeds perpendicularly downward, passes between the anterior and internal digitations of the diaphragm, and comes upon the posterior wall of the rectus abdominis muscle, where it soon divides into several branches, which descend vertically and anastomose as high as the umbilicus with the ascending branches of the epigastric artery and also with the ramifications of the external branch.

II. SUPERIOR INTERCOSTAL ARTERY.

§ 1399. The superior intercostal artery (dZ. intercoslalis suprema , s. prima) arises more externally than the preceding, and is given off from the posterior part of the subclavian artery. It is the smallest and the most external of the four constant branches of the latter, and varies in size. Sometimes it is very small ; in this case it arises almost always directly from the subclavian artery. It is rarely given off by the inferior thyroid artery, and it frequently arises by a common trunk with the deep cervical artery.

The distribution of this artery varies very frequently, especially in regard to its extent. It however always goes downward and outward, passing on the neck, and gives upward and downward branches, of which the lower are much larger than the upper.

The superior branches go to the transversalis colli muscle and send branches to the deep muscles of the back.

The inferior, which are a continuation of the trunk, divide into external and internal or posterior branches.

The external or intercostal branches (R. interossei) proceed along the lower edge of the first and second ribs, between the intercostalés interni and externi muscles. They generally do not extend very far forward and divide into two ramuscules, an upper and a lower, which follow, the former the lower edge of the upper rib and the second the upper edge of the lower rib, and are distributed in the posterior part of the intercostales muscles between which they proceed, and anastomose before with the superior anterior intercostal arteries (§ 1397). Sometimes we find two branches in the same intercostal space, one of which gives off two twigs.

The posterior , internal or dorsal branches ( R . dorsales) usually arise more or less opposite the external and divide like them into two ramuscules, the internal of which is almost always larger than the other, and enters into the spinal canal through the intervertebral foramen, is distributed to the spinal membranes and the spinal marrow, and anastomoses with the spinal arteries which arise from the vertebral artery ; while the external, proceeding between the ribs goes backward, where


268


DESCRIPTIVE ANATOMY.


it enters the deep muscles of the back, the multifidus spinse and the spinalis dorsi.

When the superior intercostal artery is very small, it is distributed only to the first intercostal space, but its branches generally extend to the second.

It more rarely gives origin, as we have already said, to the deep cervical artery, and it also gives off very near its origin an esophageal or bronchial artery (A. Å“sopliagea et bronchialis), which varies in size and turns inward and forward, sending branches to the lower part of the trachea, also to the centre of the esophagus, and likewise gives them to the bodies of the upper dorsal vertebrae, and communicates by broad anastomosing branches with the other esophageal and bronchial arteries.

§ 1400. The subclavian artery gives off those branches only which we have described. Sometimes however it sends from its lower and anterior side a considerable branch to the lymphatic glands in the upper region of the chest. It also gives off above the lower extremity of the scalenus anticus others, which go outward to some of the axillary glands.

§ 1401. The artery of the upper extremity then assumes a transverse direction, separates from the trunk, goes downward and outward between the scalenus médius and anticus, and is called the axillary artery.

II. AXILLARY ARTERY.

§ 1402. The axillary artery {A. axillaris) extends from the scaleni muscles to the lower extremity of the axilla. It is situated between the chest and the arm, its upper part being nearer the former, while its lower part approaches the latter because it proceeds obliquely downward and outward. For a short space its upper part is covered only by the skin and the platysma myoides muscle ; below we find the clavicle before it, as it passes behind its centre the subclavius muscle, and still lower the outer part of the pectorales muscles. Backward and outward we observe, above, the brachial plexus, then the subscapularis muscle, the scapulo-humeral articulation, and the tendon of the latissimus dorsi muscle. On its inside it has, above, the first two ribs, below, the serratus magnus muscle.

It is imbedded in a very loose cellular tissue, and is surrounded by the axillary glands, and is attached but feebly to the adjacent parts, excepting a small portion of its upper part. As in this place it rests on the first and second ribs, it may easily be compressed whenever an operation near or within the scapulo-humeral articulation requires.

§ 1403. Several branches, which are not very constant, arise from this artery. The principal, regarded from above downward, are the external thoracic arteries, the inferior scapular artery, and the circumflex arteries. These branches vary in respect to volume, number, and origin, because sometimes many of them arise by a common trunk, and


ANGEIOLOGY.


269


again sometimes one or more come much lower than usual from the brachial artery, or finally in some cases by a trunk in common with the deep brachial artery.

Besides these branches the axillary artery also gives off, in part or entirely, far outward above, one or more of the external thoracic arteries, the transverse scapular artery, so that the principal portion of this latter artery arises at its usual place, but its smallest branch distributes itself to the subscapularis muscle. This anomaly is very remarkable, because it gradually leads to another, which is much greater, where the transverse scapular artery is entirely deficient, or at least is very small ; so that the branches usually given to the muscles of the scapula come from the superficial scapular artery.

I. EXTERNAL THORACIC ARTERIES.

§ 1404. The external thoracic arteries (A. thoracicce externce, s. alares) vary in number from three to six.

Some arise from the inside, others from the outside of the axillary artery.

§ 1405. The former are usually smaller than the latter. They go principally to the superior external intercostal muscles, to the pectoralis minor muscle, to the axillary and thoracic glands, and go downward and forward even to the skin. Sometimes we find only one, and again there are two, which are then much smaller. One of these two arteries, and when there is only one, that one usually arises highest from the trunk of the axillary artery ; it is then termed the superior external thoracic artery (A. thoracica externa suprema, s. prima), and is also called the small external thoracic artery {A. thoracica externa minor), because it is always smaller than the others.

§ 1406. The second external thoracic artery is rather constant and is called the acromial artery ( A . acromialis). It arises from the outside of the axillary artery and is sometimes single and sometimes double. In the latter case, some of the branches usually given off by the single trunk generally arise very near each other, from the axillary artery.

This artery gives off, first, upward and forward and upward and outward, small branches which go to the subclavius muscle ; second, others below, which go to the inner part of the upper edge of the deltoides muscle and also to the upper part of the capsular ligament of the shoulder, where they anastomose below the acromion process with the branches of the superior scapular artery.

Larger and more numerous branches arise forward, inward, and downward, above and below the pectoralis minor muscle ; they enter this muscle and also the pectoralis major muscle from within and without, and are distributed principally in them.

Others, which pass on the pectoralis minor muscle, go outward and forward toward the anterior and internal edge of the deltoides muscle, intc which they penetrate from below upward, and extend to the capsular ligament of the scapulo-humeral articulation, on the surface of


270


DESCRIPTIVE ANATOMY.


which they anastomose with the preceding and also with the branches of the inferior scapular artery and the anterior circumflex artery. They penetrate also to the posterior muscles of the scapula and to the subscapularis muscle.

A constant- branch descends along the inner edge of the deltoides muscle, between it and the pectoralis major muscle, at the side of the cephalic vein. This branch is always considerably large, and it arises sometimes directly from the axillary artery, but then it comes below all the others from which it is very remote, and no longer proceeds between the deltoides and the pectoralis major muscles, but descends below the latter, between the coraco-brachialis and the two heads of the biceps flexor muscle, and gives off considerable branches to these two muscles.

Other branches, which are still lower, go to the axillary glands, to the serratus magnus, and sometimes to the trapezius muscle.

§ 1407. The third, or, when the first or the second or both are double, the fourth or the fifth external thoracic artery, the long thoracic, or the external mammary artery ( A . thoracica externa longa , mammaria externa) is given off so constantly by the subscapular artery that it should never be described as a separate artery. We shall mention it hereafter.

§ 1408. Not unfrequently two branches, which arise from the subscapular artery, come directly from the axillary artery and form a third, fourth, or fifth external thoracic artery, which is distributed to the subscapularis muscle.

IX. SUBSCAFULAR ARTERY.

§ 1409. The subscapular artery, the inferior or common scapular artery (A. subscapularis , scapularis inferior , infra-scapularis , scapularis communis) is generally the largest branch of the axillary artery and sometimes equals this trunk in size. It arises near its inferior extremity, at the lower edge of the tendon of the subscapularis muscle ; so that its origin is covered by the brachial plexus. It is rarely given off lower down.

Its origin is very constant, and when it arises from the inferior thyroid artery it is one of the rarest anomalies, and occurs certainly only in regard to its upper part.

The volume and number of its branches vary. In its greatest development it gives off, first, the final external thoracic arteries, which we have already described, which are its first branches, and which go upward and backward and are distributed in the infraspinatus muscle ; 2d and 3d, one or two circumflex arteries of the arm ; 4th, even the deep brachial artery in whole or in part ; 5th, the long external lateral thoracic artery (§ 1407), more rarely the second, third, and the fourth branches, usually the first and the fifth.

After giving off the first subscapular branches, the artery proceeds inward and downward and divides into two branches, an inferior descending branch and a superior, which is larger, goes backward and is


ANGEIOLOGŸ,


271


the continuation of the trunk, and is called the circumflex artery of the scapula (A. circumflexa scapula,).

The circumflex artery of the scapula, shortly after giving off the ascending branch, sends off several beside, some of which are large and others small, to the outer edge of the subscapularis muscle, to the teres minor and major muscles, to the axillary glands, the skin of the axilla and of the back, and to the subscapularis muscle. It afterwards curves around the neck of the scapula, passes on its posterior face, where it is called the dorsal artery of the scapula ( A . dorsalis scapula ), when it is very much developed, penetrates partly into the bone, and ascends partly also upward and inward into the subscapularis muscle, advances on the neck of the scapula, and anastomoses with the acromial and with the superior scapular arteries ; finally, when the latter is smaller or deficient, it re-ascends below the spine of the scapula into the supra3pinalis fossa, and distributes branches to the supraspinatus and likewise to the trapezius muscle.

When it is less developed it does not penetrate deeply between the scapula and the infraspinatus muscle, but only into the posterior part of the deltoides muscle, and anastomoses with the preceding arteries on the acromion process and on the anterior edge and even in the substance of the infraspinatus muscle.

The descending branch goes inward, backward, and downward, along the external wall of the chest, in the broad muscles of the back, the lower part of the serratus magnus muscle, the intercostales muscles, the tho- • racic glands, the lower part of the subscapularis muscle, and several of the axillary ganglions.

The portion of this branch which is distributed in the serratus magnus muscle is the long external thoracic artery, which very rarely arises from the trunk of the axillary artery.

III. CIRCUMFLEX ARTERIES OF THE ARM.

§ 1410. There are two circumflex arteries of the arm (A. circumflexa, s. articidares humeri ), an anterior and a posterior.


a. Anterior circumflex artery of the arm.

§ 1411. The anterior circumflex artery of the arm (A. circumflexa anterior humeri , s. articularis anterior) often arises a little higher than the posterior, sometimes also much higher, in some cases at the same height, and sometimes still lower.

It is always much smaller than the latter, but it rarely arises from it or from the subscapular artery(l). It comes very constantly from the outer and anterior side of the axillary artery, a little above the upper

(1) We have never seen it arise from the deep brachial artery, of which Mayer (p. 123) asserts it is sometimes a branch.


272


DESCRIPTIVE ANATOMY.


edge of the tendon of the latissimus dorsi muscle. It goes outward on the anterior part of this tendon, directly on the humerus, below the common tendon of the biceps flexor and of the coraco-brachialis muscles, to which it gives ramuscules, and also to the periosteum, and divides into upper and lower branches. The latter are fewer and smaller than the former ; they turn inward, some go partly to the internal portion of the deltoides muscle, where they anastomose with the posterior circumflex artery, while the others pass downward on the tendon of the latissimus dorsi muscle, to which they give branches, and anastomose with the recurrent branches of the superficial brachial artery.

The upper branches are larger and more numerous, and proceed directly on the humerus ; they ascend toward the upper part of the humerus and give ramifications to this bone, expand in the scapulohumeral articulation, penetrate to the supraspinatus and the infraspinatus muscles, and anastomose with all the arteries of the shoulder which arise from the subclavian and the axillary arteries.

Sometimes another analogous artery exists, which distributes its branches principally to the latissimus dorsi, to the upper part of the biceps flexor, and to the brachialis internus muscles. This artery is frequently only a branch of the anterior circumflex artery.

b. Posterior circumflex artery of the arm.

§ 1412. The posterior circumflex artery of the arm (Jl. circumflcxa humeri posterior) is always much larger than the preceding. It arises from the subscapular or from the deep brachial artery by a common trunk, which varies in length but is never very long, more frequently than from the axillary artery. It very rarely forms a common trunk with the anterior circumflex artery, and when this anomaly occurs, the subscapular artery also arises from this trunk. In the former case it arises no higher, or at most not much higher, than when it comes directly from the axillary artery. But when it comes from the axillary artery it is lower than usual by the length of the whole tendon of the latissimus dorsi muscle, sometimes by about two inches ; for in all the cases at least where we have observed this arrangement (which, so far from being rare, is perhaps the most common), the deep brachial artery arose as usual. The posterior circumflex artery is then reflected from below upward, behind the tendon of the latissimus dorsi muscle, and ascends between the two heads of the biceps flexor muscle until it comes a little above the upper edge of this tendon, that is, until it rises as high as its normal origin. It then goes backward to turn on the humerus. We have sometimes seen the deep brachial artery arise very high and near the posterior circumflex artery ; but we have never found that it then came from the same trunk as the latter, which has led us to think that when these two vessels arise from a common trunk we must not consider the deep brachial artery as a branch of the pos

ANGBIOLOGY.


273


tenor circumflex artery, as Murray(l) and SÅ“mmerring(2) have done, but we must regard the posterior circumflex artery as a branch of the deep brachial. (3)

The posterior circumflex artery is reflected outward and forward on the neck of the humerus, between this bone and the long head of the triceps extensor muscle. Proceeding onward, it distributes branches to this long head, to the capsular ligament of the scapulo-humeral articulation, to the teres minor and to the outer head of the triceps muscle. After giving off these branches, which are proportionally very small, it proceeds inward on the inner face of the deltoides muscle, in which it is entirely lost, and of which it is the principal artery. It anastomoses behind and above it with the anterior circumflex, the subscapular, and the superior scapular arteries.

The axillary artery sometimes gives off, above or below these two arteries, some small branches, which enter the biceps flexor, the long head of the triceps, the teres major, and the latissimus dorsi muscles.

III. BRACHIAL ARTBRY.

§ 1413. When the artery of the upper extremity leaves the axilla at the upper edge of the tendon of the latissimus dorsi muscle, it is called the brachial humeral artery (*/2. brachialis, s. humeraria). It goes between the insertions of the teres major and latissimus dorsi muscles and the coraco-brachialis, which it covers, to the inside of the biceps flexor muscle and to the inner face of the arm ; so that it] crosses the direction of the humerus and becomes more superficial the farther it descends, since toward its lower extremity it is covered only by the brachial aponeurosis and the median vein and the skin. Its upper part rests directly on the humerus, and the lower on the brachialis intemus muscle. It usually extends to the anterior face of the humero-cubital articulation, near which it terminates in most subjects. It not unfrequently however terminates higher, and sometimes does not exist at all, and then the branches usually given off in the elbow arise in the axilla.

The largest and’uppermost branches go inward ; they form the deep brachial artery or arteries. The origin of this artery, especially when it gives off branches which usually come from the axillary artery, as particularly the posterior circumflex artery of the arm or the subscapular artery, may often be considered as a point where the brachial artery divides into two branches, a superficial, which is the continuation of the trunk, and a deep branch.

§ 1414. The deep brachial or external collateral artery, Grand musculaire du bras, Ch. (Jl. profunda humeri , s. brachii , s. collai er alis

(1) Descript, art. in tab. redacta, p. 41.

(2) Sœmmerring-, Gcfâsslehre, p. 206.

(3) This remark has not escaped Mayer, who says ( loc . cit., p. 123) that one or even both the circumflex arteries arise from the deep brachial artery in rare cases.

Vol. II. 35


274


DESCRIPTIVE ANATOMY.


magna, s. superior), usually arises below the lower edge of the latissimus dorsi muscle, above the small head of the triceps extensor muscle. It accompanies the radial nerve, which it almost always covers, penetrates between the three heads of the triceps muscle, to which it gives branches, turns from within outward upon the humerus, so that its lower extremity is situated on the outside of this bone, and commonly terminates at the articulation of the elbow, where it is distributed to the supinator longus and the extensor carpi radialis muscles. It also sends branches to the brachialis internus and to the anconeus muscle, supplies the nutricious artery of the humerus near the centre of its course, and having come to the outside of the elbow, it penetrates into the anconeus muscle, where, termed the collateral radial artery ( A . collateralis radialis, s. communicans radialis a profunda ), it anastomoses with the recurrent branch of the ulnar artery. One of these branches, which sometimes arises from the brachial artery, always lower than it but directly under it and sometimes a little distance from it, and which is always smaller, goes farther forward, descends between the long and short portions of the triceps to which it gives branches, anastomoses with the inferior lateral branch of the brachial, and communicates, under the name of the collateral ulnar artery [A. collateralis ulnaris, s. communicans ulnaris a profunda ), with the recurrent branch of the interosseous and ulnar arteries, on the inner and posterior face of the humero-cubital articulation.

Thus the deep brachial artery is distributed principally to the extensor muscles of the fore-arm. It anastomoses above with the subclavian and below with the trunk of the brachial artery and with the arteries of the fore-arm.

§ 1415. Below or above the deep brachial artery, when it is single, or even between it and the collateral ulnar artery, when the latter forms a distinct trunk, we usually see'arise a branch, which goes to the longer portion of the triceps muscle and which anastomoses with the posterior circumflex artery of the arm. This branch sometimes arises from the deep brachial artery. The brachial artery then gives off, forward, outward, and backward, at right angles, about twelve very short differently sized branches, which penetrate into the biceps and the brachialis internus muscle. Some of them go only to one of these muscles, but most of them are common to both. One of the largest, which arises from the posterior and internal part of the brachial artery, about two inches above the elbow, is called the large anastomotic or internal collateral branch, or more properly the inferior anastomotic branch, or the inferior deep brachial artery ( R. anastomoticus magnus inferior, s. A. profunda inferior ) ; the first of these terms is applied to it because it establishes a communication between the trunk of the brachial artery and the arteries of the fore-arm. It proceeds inward, passing on the brachialis internus muscle, to which it gives minuscules, as also to the pronator teres, unites first by a transverse branch with the ulnar branch of the deep brachial artery, which connects it with the recurrent branch


ANGEIOLOGY,


275


of the ulnar artery ; then anastomoses on the posterior face of the articulation of the elbow with the radial branch of the deep brachial artery, and thus forms the dorsal arch of Ihe elbow ( arcus dorsalis articularis cubitalis ), and communicates in this manner with all the anastomosing branches of the fore-arm.

This branch sometimes comes from the radial artery when the latter arises much higher than usual, but its origin is not constant, and then it is sometimes supplied by the continuation of the trunk of the brachial artery — an arrangement which Bichat(l) erroneously considers as a general law in such cases. This branch comes from the ulnar artery much less frequently when the latter is given off much higher than usual. It rarely sends off from its outside, above the articulation of the elbow and directly above where the brachial artery bifurcates to give rise to the two arteries of the fore-arm, a considerable branch, which ordinarily comes from the radial artery, and which is called the recurrent radial artery {A. radialis recurrens). {2)

The two large anastomoses which we have described permit the application of a ligature upon all parts of the brachial artery, without causing any derangement in the circulation and nutrition of the forearm.

IV. ARTERIES OF THE FORE-ARM.

§ 1416. The brachial artery usually divides a little below the elbow, where the tendon of the biceps penetrates between the muscles of the fore-arm, into two branches, the radial and the ulnar artery. This bifurcation rarely and perhaps never takes place much lower, while it not unfrequently occurs higher than usual. Of the two trunks of the fore-arm, the radial is the continuation of the brachial artery as respects its direction, but in most cases it is smaller than the ulnar artery, at whatever height the brachial artery divides. It is nearer thé surface than the latter and arrives at the lower extremity without giving off any considerable branches except one, which arises from its upper part. The ulnar artery, on the contrary, soon divides into two branches, one of which is the proper continuation of the trunk, and the other the interosseous artery.

I. ANOMALIES IN THE ORIGIN OF THE ARTERIES OF THE FORE-ARM.

§ 1417. The brachial artery not unfrequently divides unusually high (§ 1416). (3) This anomaly varies in its mode and degree. The principal laws in both these respects are as follow :

(1) Anat. descrip ,, vol. iv. p. 230.

(2) This arrangement is very rare. We have seen it but once only, and we cannot find it mentioned by any writer. It does not affect the anastomoses around the elbow joint, because in this instance the recurrent radial artery did not arise much higher than usual.

(3) See our Mémoire sur les différentes variétés qu’on observe dans la distribution de l'artère brachiale; in the Journ. conrpl. du diet, des sc. méd., vol. iii. p. 31. — We


27G


DESCRIPTIVE ANATOMY,


a. In regard to mode , we observe three principal differences. In fact, the artery which arises unusually high is sometimes the radial, sometimes the ulnar, and finally sometimes the interosseous artery. Observation confirms what might be admitted on conjecture, that the first of these three anomalies is the most common and the last the rarest ; which evidently depends on the fact, that in producing the first, nature conformed to the primitive type in this respect, that the artery which is generally given off first, that is the radial artery, generally arises higher than usual. In the second anomaly, although the division takes place higher than usual, there is also an inversion, since the interosseous artery comes from the radial artery and the ulnar artery arises above the latter. Finally, in the third the anomaly is still greater, since a vessel usually given off by a branch of the brachial artery, the ulnar artery, arises directly from the trunk.

The ulnar and radial arteries are distinguished from each other when they arise higher than usual, because the former is commonly more superficial than the latter, and it then is frequently situated between the aponeurosis and the skin, an arrangement which, judging from our observations, is not always constant.

But in whatever manner this abnormal division of the brachial artery above its usual point occurs, the vessel which it thus prematurely produces is always situated in the arm, directly at the side of the superficial brachial artery.

b. In regard to the degree, we may consider the anomaly either in itself or in relation to the whole vascular system.

First, considered in regard to itself, it presents several differences, of which the principal are as follow ;

1st. The first degree consists in the existence of abnormal vessels ( vasa aberrantia), greater or less branches, which arise from the upper part of the superficial brachial artery, and empty into its lower part, or, as is more common, into an artery of the fore-arm, particularly the radial artery. In this case both the normal and the abnormal division exist, and the artery of the fore-arm, into which the abnormal vessel empties, arises in fact by an upper and a lower root. The normal type gradually passes to the abnormal formation by the increase of the first of these roots and the diminution of the second, until the latter type is perfect, when the lower root entirely disappears.

2d. A second degree is when the brachial artery divides more or less above its usual place. This division occurs in fact in all parts between the axilla and the humero-cubital articulation. The three arteries of the fore-arm differ from each other in this respect, that although the radial artery arises unusually high much more frequently than the ulnar artery, still when the anomaly exists, the ulnar artery comes from a higher point, particularly from the axillary artery itself, while the

have there given our own observations and the principal of those collected by other authors.


ANGEIOLOGY,


277


radial artery is given off near the middle of the arm. When the interosseous artery is abnormal in this respect, it arises either from the angle of the bifurcation as usual or from a higher point.

Second, considered in regard to the whole vascular system, this anomaly exists on one side only or on both sides at once. Bichat asserts that he has seen the first case oftener than the second, but our own observations and those of other anatomists prove the contrary.

This anomaly however is by no means the same on both sides in regard to the manner and the degree, and we more commonly observe differences in one or the other of these two relations than the contrary, or a perfect similitude between the two sides of the body. We cannot yet say if the anomaly is observed on the leftside more frequently than on the right when it is seen only on one side, and if it is more distinct on this side than on the other when it occurs on both sides, although this seems very probable, reasoning from the difference between the formative types of the two sides, and also from other anomalies, and from the observations which we have been able to collect.

All these anomalies are equally important in a physiological or surgical point of view. They concern physiology, because they imitate the two superficial veins of the arm. The surgeon ought always to observe them carefully, because they increase the chance of injury to the arteries of the arm, and because, when the course of the blood in the brachial artery is in any manner interrupted, it re-establishes the circulation in the upper extremity more easily.

II. RADIAL ARTERY.

§ 1418. The radial artery (A. vadialis) is usually much smaller and nearer the surface than the ulnar artery ; but in considering its direction only, it is a continuation of the trunk of the brachial, artery. It is much smaller when the recurrent radial artery arises from the brachial artery. Less frequently still it is larger, which occurs when the interosseous artery arises from it instead of coming from the ulnar artery as usual.

This artery descends a little obliquely from behind forward, along the radius, to the radio-carpal articulation, where it glides under the tendons of the extensor digitorum communis muscle, and penetrating into the palm of the hand, between the first and second metacarpal' bones, it anastomoses with the ulnar artery.

§ 1419. The first branch of the radial artery is generally the recurrent radial artery (A. recurrens radial is) ) when the latter does not come from the brachial artery, which rarely happens. It arises as rarely from the ulnar artery, which we have observed only a few times, when the radial artery arose much higher than usual ; even then the recurrent radial artery can be considered only as divided into two portions, for the radial artery gives off a muscular branch, which is detached higher than usual. In the most frequent cases, in fact, the


27S


nESCRÏPTIVE ANATOMY.


brachial artery divides into three trunks and gives off the recurrent branch at the place with the two others ; but this artery constantly arises very high from the radial artery, which even in the adult passes through but a very few lines before it is sent off. It is always the largest branch which this artery gives- to the fore-arm ; so that we may say that the radial artery, as soon as it arises, divides into two branches, one of which continues to proceed in the direction of the trunk and is the proper radial artery, and the other is smaller and is the recurrent artery. The latter gives branches to the pronator teres, the supinator longus, the supinator brevis, and the extensor carpi radialis muscles, to the capsular ligament, to the inner portion of the triceps extensor, and is reflected from below upward, between the supinator longus and the extensor carpi radialis longus, to anastomose with the recurrent radial artery given off by the deep 'brachial artery on the inner tuberosity of the humerus.

At the same place, sometimes a little higher, the radial artery gives off a small recurrent branch, which goes into the lower part of the inner portion of the brachialis internus muscle. It then gives off from its outer and inner sides, and at right or nearly right angles, and very near each other, small branches, almost uniform in size, and at least forty in number. Of these, the internal are distributed to the pronator teres, the flexor carpi radialis, the flexor digitorum sublimis, the flexor pollicis longus, the pronator quadratus muscle, and the capsule of the radio-carpal articulation ; while the external are distributed in the pronator teres, the pronator quadratus, and the extensor carpi radialis.

§ 1420. Toward the lower end of the radius, the radial artery constantly gives off a branch, which passes on the radial edge of the carpus, enters into the palm of the hand, and is called the superficial palmar artery (A. superficialis voice). This branch is always situated below the palmar aponeurosis, and proceeds toward the ulnar edge of the hand to meet the ulnar artery. This branch is sometimes and not rarely so large, that we have reason to say that the radial artery bifurcates in the place where it arises to produce it and also the continuation of the trunk which goes on the back of the hand. When this branch is small, it is frequently but not always distributed only to the small muscles of the thumb. When it is considerable, it usually but not always anastomoses with the ulnar artery to form the superficial palmar arch ( arcus volaris superficialis ), and contributes as much as the latter to produce it.

Sometimes the superficial palmar artery arises much higher than usual and proceeds in the same direction as the radial artery, with which however it cannot be confounded, as it is more superficial and less fixed in its situation.

It is essential to remember this circumstance, in order not to be in error when we wish to ascertain the state of the pulse by feeling the radial artery.

§ 1421. When the superficial palmar artery concurs to form a superficial palmar arch, it gives off very distinctly some digital palmar


ÀNGEIOLOGT.


27 9


arteries (A. digitales volares). In two preparations now before us it gives off the digital palmar artery of the thumb (A. digitalis volaris idnaris pollicis) and the digital palmar artery of the index finger ( A . digitalis volaris radialis indicis ).

Usually, when the superficial palmar artery is not very small, the superficial palmar arch is double, because, beside the large anastomosing anterior twig of this branch, we find another, which is smaller and more transverse and posterior.

However small the superficial palmar artery maybe, and even when it does not contribute to form the superficial palmar arch, it however is never entirely deficient, and always anastomoses with the continuation of the trunk of the radial artery at the bottom of the palm of the hand. We have never seen it arise except under the pronator quadratus, or at least toward its posterior edge, and constantly below the place where the radial artery rests almost directly on the radius. We must except some but not all those cases, where the radial artery arises from the brachial artery extremely high, and, imitating the type of the latter, bifurcates unusually high, for instance near the elbow.

§ 1422. After giving off the superficial palmar artery, the continuation of the trunk of the radial artery goes usually on the back of the hand, passing between the styloid process of the radius and the os trapezium ; but sometimes it is reflected higher on the outer face of the radius and of the fore-arm, and produces the following branches :

1st. Branches which go to the ligaments of the carpus and also to the flexor brevis pollicis and the abductor pollicis proprius.

2d. The dorsal artery of the thumb ( A . dorsalis pollicis), which arises from its outside, extends along the radial edge of the metacarpal bone of the thumb and of all the phalanges of this finger, anastomoses with its digital palmar artery, and rarely arises from the superficial palmar artery given off by the radial artery.

3d. The dorsal artery of the carpus (A. dorsalis carpi radialis) arises from the inside of the radial artery, more or less opposite the preceding, goes transversely toward the ulnar edge of the hand, and passing under the tendons of the extensor muscles, directly on the dorsal ligaments of the carpus, anastomoses with some small branches of the radial artery which were given off higher than the latter, then with the extremity of the interosseous artery, finally with the dorsal branch of the ulnar artery, and thus forms the dorsal arch of the carpus ( arcus dorsalis carpi), which resembles an arch less than a net-work with large meshes.

§ 1423. The dorsal interosseous arteries (A. dorsales interosseÅ“) arise principally from this arch. They proceed from behind forward in the spaces between the metacarpal bones from the second finger to the fifth, go to the external interosseous muscles, and are continuous, first, forward, with the corresponding digital arteries between the posterior extremities of the first phalanges, in the*place where the trunk of these arteries bifurcates ; second, with the inferior metacarpal arteries, whence results


280


DESCRIPTIVE ANATOMY.


a large circle of anastomoses between the dorsal and the palmar branches of the arteries of the fore-arm.

§ 1424. Next come smaller ramifications, which enter the abductor indicis proprius muscle and the ligaments of the carpus ; then, between the posterior extremities of the first two metacarpal bones, arise the dorsal cabital artery of the thumb (A. dorsalis ulnaris pollicis) and the dorsal radial artery of the index finger (A. dorsalis radialis indicis ), which arise sometimes separately and sometimes by a separate trunk.

§ 1425. When the radial artery has given off these branches, it enters into the palm of the hand between the first two metacarpal bones and the adductor indicis muscle, goes transversely toward the ulnar edge, and anastomoses with the ulnar artery, which meets it so as to form a deep palmar arch ( arcus volar is profundus), and contributes to produce it more than the latter. When passing on the posterior extremity of the metacarpal bone of the index finger, it gives rise to the large artery of the thumb ( A . princeps , s. magna pollicis). The latter divides sometimes into the palmar radial and the palmar ulnar artery of the thumb ( A . volar is pollicis radialis et ulnaris ), sometimes furnishes only one of these two branches, while the other arises near the superficial or from the deep palmar arch ; but it always anastomoses by one or two large branches with the radial and the ulnar dorsal arteries of the thumb, even when the corresponding palmar arteries do not arise from it.

The radial artery rarely divides, when passing through the first interosseous space, into two branches, one of which is the continuation of the trunk and goes into the palm of the hand, while the other is smaller, passes over the internal belly of the first external interosseous muscle, and anastomoses with the superficial palmar arch, giving origin to the palmar cubital artery of the thumb (A. volaris ulnaris pollicis), where it divides into this artery and the palmar radial artery of the index finger ( A . volaris radialis indicis), which formation is remarkable because it strengthens the resemblance with the arteries of the other fingers, as this dorsal branch then represents the first dorsal metacarpal artery, which is the largest. Sometimes but very rarely these arteries do not arise from the large artery of the thumb, but from the superficial palmar arch and directly from the superficial palmar radial artery. In this case the palmar and the large arteries of the thumb, which are proportionally smaller, give off only the dorsal arteries of the thumb. Nevertheless, we have never seen this arrangement except when the radial and the palmar radial arteries arose unusually high.

Even at the place where the large artery of the thumb arises, and only little more on the anterior side of the radial artery, a very constant branch arises, which however varies in size ; this goes inward and passes directly on the palmar face of the second metacarpal bone, gives branches to the adductor pollicis muscle, and contributes more or less to form the palmar arteries of the index finger. This however is not always the case ; so that the radial artery of this finger always comes


ANGEIOX.OGY.


2S1


from the branch of which we were speaking, as Scemmerring pretends ; for we have sometimes seen, notwithstanding the considerable size of the latter, the radial artery of the index finger coming from the superficial palmar arch. We may then, in order to express the analogy between it and the large artery of the thumb, term this branch the large artery of the index finger {A. princess indicts').

Wo shall describe the deep palmar arch when speaking of the ulnar artery.

III. VLNAR ARTERY.

§ 1426. The ulnar artery (A. ulnaris, s. cubitalis) is generally the largest of the two branches produced by the bifurcation of the brachial artery ; it goes toward the ulna sooner after arising, passes below the pronator teres, and proceeds toward the hand, along the ulna, between the flexor ulnaris and the flexor digitorum profundus muscles, and is always situated deeper than the radial artery. It gives off near its origin a small or large branch, the anterior recurrent ulnar artery, which penetrates to the lower extremity of the inner portion of the triceps extensor and also into the upper extremity of the pronator teres, and corresponds to a similar branch given off by the radial artery.

§ 1427. It then sends off the recurrent or the posterior recurrent ulnar artery (A. recurrens ulnaris, s. cubitalis), which is generally much larger than the preceding, and proceeds from below upward between the flexores digitorum sublimis and profundus and the flexor ulnaris, distributes branches to these muscles, penetrates through the latter, and ascends between the inner condyle of the humerus and the olecranon process, and unites with the inferior and internal collateral artery which comes from the brachial artery, and thus forms the largest anastomosis which exists around the humero-eubital articulation. This artery- always arises much low’er than the recurrent branch of the radial artery. It comes very constantly from the ulnar artery, when the latter arises as usual from the brachial artery ; at least we have never seen it arise directly from the humeral artery, as does the recurrent radial artery, which undoubtedly must be attributed to its arising so low. On the contrary, in all those cases where the ulnar artery ascended unusually high, the recurrent artery was not given off by it but by the interosseous artery ; so that then even the anomaly approached as near as possible the normal formation.

§ 1428. Soon after giving off this branch, the ulnar artery divides into two others, the proper ulnar artery and the interosseous artery (A. interossea ), which is usually smaller than the other. The latter is rarely given off by the brachial artery, either at the usual place of its bifurcation(l) or above this point.(2) When the ulnar artery arises

(1) Barclay, Description of ihe arteries of the human body; lathe Edinb. Med. and Surg. Journ., vol. viii p. 468.

(2) Monro, Outlines of Anatomy, vol. iii. p. 304,

Von. II ‘ 36


282


DESCRIPTIVE ANATOMY".


unusually high, the interosseous artery is a branch of the radial artery,, whence it arises in the same region of the fore-arm, although it comes from a different artery.

From these two causes the ulnar artery is much smaller than usual when it arises uncommonly high. This diminution of caliber is sometimes observed in it, although its origin is not abnormal, because the interosseous artery, although very rarely, arises from the radial.

The interosseous artery gives off near its origin one or two very constant branches, which descend into the upperpartoftheflexoresdigitorum sublimis and profundus, into the flexores carpi radialis longus and brevis muscles, and the pronator teres. Lower down it divides into two branches, nearly equal in size, one of which is a little larger and is a continuation of the trunk, and descends on the anterior face of the interosseous ligament, while the other passes above the upper edge of this ligament to go to the dorsal face of the fore-arm. This branch is the superior perforating artery (A. perforons prima suprema), which soon divides into two branches. The smaller, which is however considerable, is called the recurrent interosseous artery {A. recurrens interossea ), reascends above the extensor carpi ulnaris muscle, between the radius and the ulna on one side and the anconeus muscle on the other, and empties into the dorsal arch of the articulation of the elbow. The larger descends between the origin of the extensor longus and the abductor pollicis longus on the one side, the extensor digitorum and the extensor carpi ulnaris on the other, along the ulna to its lower extremity, and in its course gives off numerous branches to the muscles which we have mentioned.

§ 1429. The trunk of the interosseous artery descends in most of its extent on the anterior face of the interosseous ligament, between the two bones of the fore-arm, a little nearer the ulna than the radius, gives small twigs to all the flexor muscles, and also supplies six or seven branches, the inferior perforating arteries (A. perforantes minores inferiores ), which pass through the interosseous ligament, glide on the posterior face of the fore-arm, and are distributed in the extensor muscles. The arterial trunk terminates in passing above the upper edge of the pronator quadratus to the dorsal face of the fore-arm, where it divides into three or four branches, nearly equal in size. One or two of these branches are distributed partly in the extensor and the abductor pollicis and partly also pass under the tendons of these muscles, resting directly on the bone, turn on the radius, and anastomose with the branches of the radial'artery. The second or the third, which retrogades on the ulna, anastomoses with the superior perforating artery. The third or the fourth, which is the continuation of the trunk, descends between the two bones of the fore-arm and forms the dorsal arch of the carpus ( arcus dorsalis carpi) on the back of the carpus, and divides into a middle and at least two lateral ramuscules, which communicate with, the carpal branches of the radial and ulnar arteries.


ANGEIOLOGY.


2SS


§ 1430. The trunk of the interosseous artery rarely gives off a long branch, which descends between the flexor muscles of the fingers to the hand and contributes to form either the superficial palmar arch or the arteries of the thumb. This is seen particularly when the ulnar artery arises higher than usual, a very remarkable circumstance, as it shows an effort to approximate the anomaly to the normal formation.

§1431. The ulnar artery, after giving off - the interosseous artery, sends off like the radial, at short intervals, numerous ramuscules, which are distributed to the muscles between which it descends, the flexors of the fingers, and the extensor carpi ulnaris muscle. Near the lower extremity of the ulnar and about an inch above the radial artery, it divides into two branches, the larger of which is the continuation of the trunk, while the other is smaller and is called the dorsal ulnar artery ( A . dorsalis ulnaris , ramus dorsalis ab ulnan). The latter is reflected above the tendon of the flexor ulnaris muscle, on the lower extremity of the ulna, sends branches to the flexor ulnaris and to the pronator quadratus muscle, also to the ligaments of the carpus, anastomoses with the dorsal branch of the radial and with the interosseous artery, gives rise to the dorsal arch of the carpus, and terminates in the fourth internal interosseous muscle, also in the muscles of the index finger, especially the abductor muscle.

§ 1432. After giving some small branches to the palmar ligament of the carpus, the ulnar artery divides, near the posterior extremity of the fifth metacarpal bone, into two branches, the superficial and the deep palmar artery ( ramus volaris superficialis el profundus.)

IV. PALMAR ARCHES.

§ 1433. There are two palmar arches ( arcus voice), a superficial and a deep.

The superficial palmar branch of the ulnar artery is usually much larger than the deep. It passes above the tendons of the flexor muscles which previously covered the ulnar artery, advances immediately below the palmar aponeurosis toward the radial edge of the hand, and anastomoses with the superficial palmar branch of the radial artery, which it always exceeds in volume, even when the latter is unusually large. These two branches join and form the superficial palmar arch ( arcus superficialis voice). This arch is not unfrequently formed entirely by the ulnar artery, which does not then anastomose with the pajmar branch qf the radial artery, or communicates with it only by some trifling ramuscules.

The collateral arteries of the fingers {A. digitales) arise from the superficial palmar arch, but not constantly in the same manner. The only rule which we can establish in this respect is, that most of the digital arteries arise directly or indirectly from the superficial arch, from the deep arch, or from both at once, and always arise two and two from a single trunk ; so that this single trunk extends from the arch to the


284


DESCRIPTIVE ANATOMY.


extremity of the first phalanx and there divides into two branches, which are unequal and often disproportional in size, which always belong to two different fingers and never to one only. These branches proceed on the palmar face of the fingers, along the radial edge of one and the ulnar edge of the other. Each finger thus receives two collateral arteries, the ulnar of which is always the larger.

The little finger usually receives a proper or .special ulnar artery, the first branch of the superficial palmar arch which goes to it, proceeding along the flexor minimi digiti brevis muscle, to which it sends numerous ramuscules.

Some distance from this branch, and very near each other, arise three very constant arteries, the. second, the third, and the fourth collateral arteries, which go, the first to the radial side of the fifth finger and the ulnar of the fourth, the second to the radial side of the fourth and the ulnar side of the third finger, and the last to the ulnar side of the second and to the radial side of the third.

Farther, we generally find a fourth common collateral artery, which divides into the artery of the radial side of the index finger and the artery of the ulnar side of the thumb.

This arrangement presents only a few unimportant anomalies, the principal of which are :

Sometimes the second collateral artery, the ulnar branch of the fifth finger, belongs not so much to the superficial as to the deep palmar arch, of which it is the posterior part, — that by means of which this arch communicates with the other ; so that it must be considered as an anastomosing branch between the two arches. The fourth collateral artery, which goes to the radial side of the third and the ulnar sid,e of the second finger, sometimes presents the same anomaly. These two differences arise because the two arteries always communicate with the deep arch by large anastomosing branches, while the other two middle collateral arteries are more insulated and more independent.

The union of several digital arteries in a common trunk, which is always very short, forms a second anomaly. To this there is a gradual transition by a case which is sometimes observed, viz. the approximation of two branches to each other.

Thus we have often seen coming from a common trunk the first and second, the third and fourth, or the fourth and fifth, which then went only to the radial side of the index finger. When the artery of the little finger does not form a small distinct trunk, but comes from the second, the common trunk is a little longer than that which appears when the branches are united, and the second goes almost always to the ulnar side of the fourth finger and the radial side of the fifth.

§ 1434. The deep or the smallest ulnar artery turns deeply from behind forward on the flexor minimi digiti brevis muscle, goes always outward toward the radial side of the hand, so that it proceeds transversely on the internal interosseous muscles to meet the deep palmar artery, with which it anastomoses, and forms the deep palmar arch


ANGEIOLOGY,


285


(arcus palmar is profundus). This arch is sometimes larger and sometimes smaller than the superficial, but smaller more frequently than larger, and its caliber is always greater on the radial than on the ulnar side, because the radial artery concurs to form it more than the ulnar artery. It is always situated farther back than the superficial arch, and is placed directly before the posterior extremity of the metacarpal bones.

§ 1435. The deep palmar arch produces,

1st. From its anterior side or its convexity, the palmar interosseous arteries (A. interossece volares ), or the inferior perforating arteries (A. perforantes inferiores), which are the largest of all its branches.

These arteries go to the internal interosseous muscles in the spaces between the metacarpal bones, give branches to the muscles in these regions, and one or the other at least, and sometimes all. anastomose at their anterior extremity with the collateral arteries of the fingers, where the latter bifurcate, and also with the superior interosseous arteries.

They correspond to the collateral arteries of the. fingers, but are usually much smaller. The first however is generally much more developed than the others. Hence we have prop'osed to term it the large artery of the index finger (A. indicis princeps) (§ 1425). Sometimes howeyer other arteries among the inferior interosseous arteries are unusually large ; so that they are as large or nearly as large as the common trunks of the collateral arteries which arise from the large arch, and the digital arteries also arise as much and even more from the deep than from the superficial arch.

Sometimes but more rarely they exceed almost all the collateral arteries of the fingers in volume, and the palmar arteries of the fingers arise more than they from the superficial arch, as is frequently the case with the index and little finger.

2d. The superior ox posterior perforating arteries (A. perforantes, s. posteriores , s. superiores) arise from the convexity of the deep palmar arch. They penetrate between the posterior extremities of the metacarpal bones, give ramifications to the posterior part of the lumbricales muscles, and come on the back of the hand, where they anastomose with the anterior part of the dorsal arch of the carpus and with the superior metacarpal arteries, which are given off by this arch less frequently than by them (§ 1432).

§ 1436. Thus the two palmar arteries concur simultaneously to produce the digital arteries. The superficial arch contributes most to the origin of the palmar branches of the third, of the fourth, fifth, and of the ulnar side of the index finger ; the deep, on the contrary, assist more in forming the palmar branches of the thumb and of the radial side of the index finger. Sometimes however the latter arise entirely from the superficial arch, but this is true of the radial artery of the index finger and the ulnar artery of the thumb more frequently than of the radial artery of the thumb. In this case the two branches arise by a common trunk. When all the digital arteries, not excepting those of


â– 386


DESCRIPTIVE ANATOMY.


the thumb, come from the superficial palmar arch, this divides sometimes at the lower part of the hand into two large principal branches, one of which gives off the twigs which usually arise from the superficial arch, and the other bifurcates to give rise to the principal artery of the thumb and the radial branch of the index finger, which deserves to be remarked, as it shows that nature endeavors to approximate to the normal type even in the greatest anomaly. The superficial palmar artery of the radius does not then exist or is very slightly developed. It sometimes, on the contrary, contributes more than usual to produce the superficial palmar arch, and then it gives off also all the digital arteries ; but the ulnar and the radial arteries are not then always connected, except by a small anastomosing branch, which is sometimes entirely deficient, and each of the two arteries produces only the branches which go to the corresponding side of the hand.

The two palmar arteries anastomose at the bifurcation of the digital arteries and produce the two collateral arteries. They communicate by long branches, which are usually much smaller than the common trunks of the digital arteries. The largest and most constant of these branches are situated between the ulnar artery of the little finger and the common artery of the second and third.

The dorsal arch of the carpus and the deep palmar arch communicate by the posterior or superior perforating arteries and the dorsal interosseous arteries. The last and the inferior interosseous arteries establish a communication between these two arches and the superficial palmar arch.


V. DIGITAL ARTERIES.

§ 1437. Although the digital arteries arise in most cases from the superficial arch (§ 1433), we may however say, that the deep arch (throwing out of view what happens more or less frequently, that some are given off by this latter alone) and the dorsal arch of the carpus contribute to produce them ; so that the obliteration of one of these sources may be easily replaced by the enlargement of the other.

Each finger receives at least four constant branches, two palmar and two dorsal ; the latter are smaller than the others. The two palmar branches anastomose on the palmar side, either on one phalanx only, or on several, or even on all, by one or more transverse branches, the convexity of which is turned a little forward. However, among these anastomosing branches, the only ones which are constant are those which are very much developed on the lower face of the third phalanx and which are usually double. Besides, the palmar branches anastomose with the dorsal by an arch on the back of the phalanges, especially the third. Each palmar artery gives off in its course at least ten or twelve branches, which go to the nerves, tendons, ligaments, and skin. It also gives, from the arch it forms at the extremity of the finger,


ANGEIOLOGV.


287


by anastomosing with that of the opposite side, at least as many ramuscules, which go to to the skin.

CHAPTER III.

THORACIC PORTION OF THE AORTA.

§ 1438 . From the thoracic portion of the aorta or from the pectoral aorta ( aorta thoracica) (§ 1329 ) arise numerous but very small arteries, and hence the aorta after giving them off is not sensibly smaller than when proceeding along the chest after the three trunks have arisen from its arch.

Many of these branches are constant, but others are not ; and they frequently arise totally or at least in part from other arteries.

The former arise from the lateral parts or from the posterior side of the pectoral aorta in its whole length ; the others come principally from its upper and central part and from its anterior side.

A. ANTERIOR BRANCHES.

§ 1439 . The anterior branches of the thoracic artery are principally the inferior bronchial {A. inferiores bronchiales), the esophageal (A. esophageœ), and the posterior mediastinal arteries (A. médiastinales posteriores).

The inferior bronchial arteries which arise from the aorta vary much in number and origin.

They vary in number from two to four. There are commonly two on each side for each bronchia. The inferior are a little larger than the superior. The largest and most constant generally arise an inch below the extremity of the arch of the aorta. The right is almost always a branch from the first intercostal artery of the aorta, which gives it off after coming on the right side of the vertebral column, passing behind the esophagus. . But sometimes it arises directly from the aorta, and the latter frequently gives off on the right a second inferior bronchial artery when the usual one arises from the first intercostal branch of the aorta, or even when the left bronchial artery sends ramifications to the right bronchia. The left, on the contrary, arises directly from the aorta, and passes before the esophagus to go to its bronchia ; but as it is larger than that on the right side, it commonly gives also some branches to the bronchia of the right side.

The small superior bronchial arteries, which are less considerable and inconstant, belong generally speaking more to the left than to the right bronchia.

Besides these ramuscules, which may be called the middle bronchial arteries, each bronchia receives from the subclavian artery (§ 1372 ) or from the corresponding internal mammary (§ 1398 ), branches, called


2S$


DESCRIPTIVE ANATOMY.


the superior bronchial arteries, which are expanded in its upper part and communicate by large anastomoses with' the middle and inferior bronchial arteries.

Sometimes the aorta gives off only one bronchial artery, which often arises from it in common with the right superior intercostal artery.

The bronchial arteries are distributed not only to the bronchiæ but also in the esophagus, the aorta, the pericardium, and the thymous gland.

§ 1440. The aorta gives off, generally below these arteries, from its anterior part, several esophageal arteries, which vary in number from two to seven and which are always smaller than the bronchial arteries. These arteries communicate with the esophageal branches which arise from the bronchial arteries and also with others, which are given off by the inferior diaphragmatic arteries, with the latter, and with the arteries of the stomach. They anastomose extensively and always by very large branches.

1441. The posterior mediastinal arteries are always small and very numerous. They are distributed partly in the esophagus and particularly in the parietes of the thoracic aorta, and anastomose with each other, and also with the esophageal arteries, and with the branches of the internal mammary artery.

B. LATERAL AND POSTERIOR BRANCHES. INTERCOSTAL ARTERIES.

§ 1442. The inferior and posterior aortic intercostal arteries ( J1 . intercostales posteriores , inferiores ; s. aorticÅ“) are the lateral and the posterior branches of the thoracic aorta. We find an arterial branch in each intercostal space, but the aorta does not give. off as many as there are spaces; for, 1st, the first and second, or at least the first, usually receive their vessels from the superior intercostal artery, a branch of the subclavian artery (§ 1399).

2d. Several intercostal arteries, particularly the upper and the lower, and sometimes also the middle, although then the upper and lower do not participate in the anomaly, arise by common trunks, both the opposite arteries of the right and left sides, which correspond in respect to the intercostal space into which they penetrate,, as well as those which are situated one above the other on the same side. This -last anomaly is more rare than the first. When two intefcostal arteries arise by a common trunk, we have always observed hitherto that the inferior is the continuation of the trunk and proceeds in its direction, while the superior generally passes before and more rarely behind the neck of the rib to arrive at the intercostal space, in which it is then distributed as usual.

A common trunk usually divides only into two secondary branches, but sometimes also it gives off several, of which the superior aortic intercostal artery(l) gives frequent examples.

(1) In opposition to the superior intercostal, which arises from the subclavian artery.


ANGEIOLOGY.


289


The fact that the superior and inferior intercostal arteries generally arise by a common trunk, is curious in two respects :

1st. Because it furnishes a new instance of the resemblance between the upper and the lower extremities of the same region.

2d. Because the superior aortic intercostal artery and the superior intercostal which arises from the subclavian artery, especially correspond.

The two arrangements are then a repetition, in the central portion of the vascular system, of the resemblance demonstrated between the upper and the lower part of this system, when we consider the diaphragm as the line of demarkation between the two portions.

Finally, the two series of intercostal arteries are not perfectly similar, and the two intercostal spaces of one side frequently receive their vessels from a common trunk while on the other side they arise separately^ 1)

We generally find on each side eight (2) aortic intercostal arteries because the upper intercostal artery gives them to the first two intercostal spaces, and the third and fourth receive the blood from the branches of the first aortic intercostal artery.

The number of the intercostal arteries is very rarely increased by one, which happens when the upper intercostal artery, usualty furnished by the subclavian, arises directly from the pectoral aorta. (3) This is more frequently the case than that the first aortic intercostal artery is distributed only in the third intercostal space.

The number of these arteries is then one less, and is reduced to seven. Then sometimes the first goes to the second, third, and fourth intercostal spaces ; sometimes, and more frequently, two of the inferior arise by the same trunk.

All the intercostal arteries generally come more from the back side of the aorta than from its lateral part, they arise near each other, and the right and the left at the same height.

They are all detached from the aorta at slightly acute angles, and go upward toward the intercostal space to which they correspond, passing on the bodies of the vertebrae and the necks of the lower ribs.

The distance between their origin and their intercostal space is much greater, and the angle which they make with the trunk is more acute above and more obtuse below in the upper than in the lower. They never, not even the lowest, form a right angle with the aorta.


(1) Bichat is mistaken in saying- that, considered on the two sides, these arteries are almost perfectly similar (An. descript, vol. iv. p. 253).

(2) Bichat asserts erroneously, that there arc usually nine. Murray and Soemmerring are also mistaken in saying there are never less than eight. Mayer is still more in the wrong ; he admits that there are usually eleven aortic intercostal arteries on the right side, and ten on the left.

(3) Monro seems to regard this formation as equally common with the rule (Outline s, p. 322); but it is in fact very rare, a circumstance which is not uninteresting, inasmuch as the pectoral aorta seems to have, directly above the origin of the intercostal artery, a great tendency to contract very much or to close entirely.

Vol. II. 37


290


DESCRIPTIVE ANATOMY.


These arteries become smaller in proportion as they are lower. It is however necessary to say something more exact on this subject. In fact the first intercostal artery is much larger than the others, partly because it is distributed to a greater number of intercostal spaces, and because on the right side at least it gives rise either partly or wholly to the right bronchial artery.

The right intercostal arteries, from the situation of the aorta on the left side of the vertebral column, are longer than the left, by all the right portion of the vertebra on which they pass.

Near their origin they give ramifications- to the esophagus and generally to all the parts contained in the posterior mediastinum, and divide usually near the head of the ribs into two branches, a posterior and an anterior.

The posterior branch (R. posterior , s. dorsalis) passes through the intercostal space to go backward, gives some ramuscules to the vertebrae, also sends some to the spinal marrow, through the intervertebral foramina, but is distributed principally to the posterior muscles of the trunk situated in the groove between the vertebral column and the ribs, the multifidus spinæ and the longissimus dorsi. Its superficial ramifications reach even to the skin, and it anastomoses by ascending and descending branches with the adjacent superior and inferior dorsal branches.

The anterior , thoracic , or intercostal branch (I?, anterior, thoracicus, intercostalis ) is generally much larger than the dorsal, which exceeds it particularly in volume in the superior intercostal arteries, and which, from its direction, may be considered as the continuation of the trunk ; it proceeds first between the pleura and the posterior part of the intercostalis internus muscle, to which it is feebly united, then passes between the intercostales interni and externi muscles, and soon divides into two branches.

The inferior branch ( R . costalis inferior ) is much smaller than the other, goes forward, along the upper edge of the lower rib, soon passes on the internal face of this bone, gives ramifications to its periosteum, furnishes some, although very few, to the intercostales muscles, and terminates by anastomosing with the upper branches of its trunk and of the intercostal artery which come directly after.

The upper branch ( R. costalis superior) is the continuation of the trunk, and proceeds below the upper rib of its intercostal space in the groove, on its lower edge, goes forward, gives ramuscules to the ribs, to the intercostales, the abdominal, and the dorsal muscles and to the diaphragm, and anastomoses with the anterior intercostal arteries which come from the internal mammary artery, and also with the epigastric and the external iliac arteries.

The first intercostal artery is distinguished from the others by the characters we have already mentioned. It supplies several, and sometimes even three intercostal spaces.


ANGEIOLOGY,


291


The right and left differ, as the first usually gives off the right bronchial artery while the second is distributed more frequently than it in a third intercostal space.

Although this latter arrangement is not constant, we have never seen the first two intercostal arteries correspond in regard to the former.(l)

Next to the first the last is largest of any, and sometimes exceeds it in size. It arises behind the lumbar portion of the diaphragm ; after giving some branches to this muscle it passes almost entirely below and before it, and, proceeding outward and forward, behind the upper portion of the quadratus lumborum muscle, it divides into several large branches, which are distributed in this muscle and also the broad muscles of the abdomen, then descend to the crest of the ilium, and anastomose frequently with the lumbar and with the circumflex iliac arteries.

The two inferior intercostal arteries often arise by a single trunk, which comes from the posterior part of the aorta. They are sometimes deficient on one or on both sides ; they are then replaced by the first lumbar artery.


CHAPTER IV.

ABDOMINAL PORTION OF THE AORTA.

§ 1443. The abdominal aorta gives off in fact fewer branches, but most of them are larger than those which arise from the thoracic aorta. The reason of this is that the abdomen is larger than the chest, and the organs which it contains are also much larger. A farther reason is that all these organs receive their arteries from the abdominal aorta, while those of the thoracic viscera do not all come from the thoracic aorta.

The branches of the abdominal aorta may be divided into anterior, lateral, and posterior. The anterior and the posterior are however, at least in great part, sometimes more and sometimes less lateral than usual.


I. ANTERIOR BRANCHES.

§ 1444. The anterior branches of the abdominal aorta belong almost exclusively to the digestive organs. There are usually three, the cœliac , the superior, and the inferior mesenteric arteries. Some

(1) As Soemmerring seems to admit (p. 249), since he thinks that the first two intercostal arteries are large because they give off the bronchial arteries. Bichat agrees witli us (p. 250) on this subject.


292


DESCRIPTIVE ANATOMY.


times however we find only two, the first two arising by a common trunk. But they oftener exceed three.

The aorta on coming into the abdomen, having passed through its opening in the diaphragm, usually gives some small branches to the pillars of this muscle, to the thoracic canal, and to the renal capsules.

It seldom gives off the inferior diaphragmatic arteries, either separately or by a common trunk. These arteries more frequently arise from the cœliac artery, consequently they will be treated of when speaking of that artery.(l)


I. C CELIAC ARTERY.

§ 1445. The cœliac artery, Opislro gastrique , Ch. (A. cœliaca),(2) is usually the largest, and arises the highest, as it comes off at a right angle from the aorta, between the pillars of the diaphragm.

Usually and in fact almost always, when its trunk is not exceedingly short, it gives off first, from its upper side, the superior diaphragmatic arteries (A. diaphragmatic ce, s. phrenic Å“ majores, s. principes, s. inferiores ), which arise sometimes separately and sometimes by a very short common trunk. Sometimes one of these arteries comes from the aorta and the other from the cÅ“liac artery ; more rarely one or both of them are given off by one of the branches of the cÅ“liac, or even by the renal, or finally by the inferior capsular artery. They ascend directly on the pillars of the diaphragm, to which they give off branches, and also supply the middle capsular arteries {A. suprarénales medial), which go to the renal capsules ; and when they have arrived at the upper extremity of the pillars, divide into an anterior and a posterior branch.

The posterior branch, which is the smaller, is sometimes, at least On one side, given off wholly or partially by the aorta. Even when the principal trunk arises from the cÅ“liac artery, it sends considerable branches to the renal capsules ; these are called the superior capsular arteries (A. suprarenales superiores ). It then goes outward, below and behind the tendinous centre of the diaphragm, to be distributed principally in the lumbar portion of this muscle.

The anterior branch is much larger, and must be considered as the continuation of the trunk ; it goes forward, along the esophagceal opening, before which it divides into two branches, an anterior and internal, and transverse which is much smaller, and is distributed to the central portion of the diaphragm, and anastomoses with that of the

(1) Monro is mistaken in saying that these arteries arise from the aorta (vol. iii. p. 333). Mayer (p. 656) also seems to think this is the most common arrangement. Murray (p. 61) and Sœmmcrring (p. 252) think that they arise from the aorta asfrequently as from the cœliac artery. Bichat is more correct (p. 283) in saying that they arise from the cœliac artery more frequently than from the aorta. This remark was made long before him by Haller (part 2, notes to vol. i. p. 6).

(2) A. F. Walther, De arteriis eœliuci Leipsic, 1729.


ANGEIOLOGY.


293


opposite side, while the external is much larger, goes outward, and gives ramuscules to most of the costal portion of the diaphragm.

The inferior diaphragmatic arteries go principally to the lower face of the central portion of the diaphragm. They communicate with the external which arise from the internal mammary, with the inferior intercostal, and the lumbar arteries ; also pass through the diaphragm, enter the chest, and give off, in this cavity, the pericardiac and the inferior mediastinal arteries.

§ 1446. The cÅ“liac trunk after and sometimes also before giving off the inferior diaphragmatic arteries divides most generally into three branches ; these are the coronary arteries of the stomach, the hepatic and the splenic artery. These three branches form the tripus Halleri.

§ 1447. The coronary artery of the stomach, Stomogastrique, Ch. (A. coronaria ventriculi , s. gastrica superior, major sinistra, gastrohepatica sinistra), is usually much smaller than the other two branches of the cœliac artery. Sometimes, but rarely, it arises from the aorta before the latter, either alone or by a trunk which is common with it, sometimes with only one of the inferior diaphragmatic arteries, particularly that of the left side, and sometimes with both.

It proceeds first upward and forward, then to the left, and gives off,

1st. Several inferior esophagœal arteries (A. esophagece inferiores) .

2d. Several posterior cardiac arteries {A. cardiacce posteriores ), which are distributed around the superior orifice and on the large curvature of the stomach, and descend principally on its posterior face.

3d. Very frequently, and even almost always, the left hepatic artery.(l)

The anterior and superior gastric and the other inferior esophagœal arteries, arise from this artery or from the following branch.

4th. The gastric branch (R. gastricus). When the coronary artery of the stomach gives off the left hepatic artery, it bifurcates to give origin to it and also to the gastric branch. The latter usually divides into several large anterior and posterior ramuscules, which are distributed on the anterior and posterior faces of the stomach, and anastomose with each other and with the preceding. It always gives off a greater or less anastomosing branch, which follows the small curve of the stomach, and goes toward the right side, where it anastomoses with the pjdoric artery.

§ 1448. The hepatic artery (A. hepatica) is larger than the preceding. Sometimes it does not give off the usual number of branches. The anomaly may then occur in several different ways. In fact the hepatic artery is sometimes divided into two trunks, which arise one from the cœliac artery as usual, the other from the coronary artery of the stomach, or from the superior mesenteric artery, or more rarely from

(1) Hence the term g astro-hepatic which has been applied to it. In this case the coronary artery of the stomach is not, as generally, much smaller than the other two branches of the cœliac artery, but it is often as largo as the hepatic, especially when it gives off at the same time one or both of the inferior diaphragmatic arteries.


294

DESCRIPTIVE ANATOMY.


the aorta ; sometimes there are three trunks, one of which arises from the cceliac, a second from the superior mesenteric artery, a third from the aorta.

Sometimes but more rarely the hepatic artery arises entirely from the aorta. The rarest anomaly is that where it comes entirely from the superior mesenteric artery.(l)

The trunk of the hepatic artery proceeds transversely to the right side ; it then goes a little obliquely forward and upward, entering into the transverse fissure of the liver.

Just before arriving at the liver it divides into two branches, the right gastro-epiploic artery and the hepatic branch.

§ 1449. The right gastro-epiploic artery (Jl. gastrica dextra inferior , coronaria ventriculi dextra inferior , gastro-epiploica dextra. pancreatico-duodenalis), which is much smaller when only one hepatic trunk exists, but which in other cases is as large as the hepatic branch, goes downward, and to the left, toward the origin of the duodenum, passes below this intestine, between it, the pylorus, and the pancreas, reaches the great curvature of the stomach, proceeds along it from right to left, and anastomoses with the left inferior gastro-epiploic artery.

In its course it gives off the following branches :

1st. Before arriving at the duodenum and passing under this intestine, one or two considerable branches, the pancrealico-duodenal arteries (A. pancreatico-duodenales), which descend along the concavity of the duodenum, give to it numerous ramuscules, and also give origin to one or two retrograde pyloric arteries (A. pyloricce inferiores) ; the latter, which are distributed around the pylorus, give off other considerable branches to the head and to the right portion of the pancreas, and anastomose extensively with the branches of the superior mesenteric artery.

One or more of these anastomosing branches are sometimes so large that we might consider the right gastro-epiploic artery rather as a branch of the inferior mesenteric than as arising from the cœliac artery.

2d. The continuation of the trunk proceeds along the large curvature of the stomach, gives a great number of ascending branches to the two thirds on the right of this viscus, and sends others, which are less numerous and which descend between the two layers of the large epiploon, where they form the right and middle epiploic arteries (A. epiploicæ dextrœ et inediœ). These branches anastomose with each other and with those of the left gastro-epiploic artery by large arches.

Near the commencement of the left third of the stomach the trunk of the right gastro-epiploic artery gradually diminishes and becomes very small, so that we can easily perceive the limit which separates it from the left gastro-epiploic artery, with which it anastomoses in this place.


(1) Haller, Ic. anat., part viii. p. 36.


ANGEIOLOGY.


295


§ 1450. From the hepatic branch ( R . hepaticus ), sometimes also from the trunk of the hepatic artery, before it gives off the right gastroepiploic artery, arises a smaller branch, called the superior pyloric artery ( A . gaslrica dextra superior , coronaria ventriculi dextra superior , pylorica superior). This branch descends towards the pylorus and anastomoses with the inferior pyloric, and with the branches of the left gastro-epiploic by small arches.

Soon after the hepatic branch divides into a right and left.

The right hepatic artery (A. hepatica dextra) is larger than the left. It is distributed to the right lobe of the liver and to the gall-bladder.

This soon divides into two branches ; the smaller goes to the middle part of the liver {A. hepatica dextra minor, A. hepatica media ) ; this sometimes arises directly from the aorta, although the origins of all the other branches are normal ; the other is greater and is the continuation of the trunk. The latter goes to the vena-porta, enters the transverse fissure of the liver, where it divides into numerous ramifications, anti almost always gives off, just before entering, one or two cystic arteries (A. cystica).

The right hepatic artery, either alone or with the right gastro-epiploic artery, not unfrequently arises from the superior mesenteric artery, an arrangement always indicated by the large anastomoses between these two arteries by means of the pancreatico-duodenal arteries. The left hepatic artery, not unfrequently, is separated from the right, and arises from the tripus Halleri by a common trunk with the coronary artery of the stomach.

§ 1451. The splenic artery (A. splenica, s. lienalis ) is the largest of the three branches of the cceliac artery in the adult, and goes to the left soon after arising, proceeding below and behind the stomach in the transverse fissure of the pancreas.

In this course it gives off,

1st. From its lower side the middle and the left pancreatic arteries (A. pancreaticÅ“ media et sinistra), which vessels are usually large and arranged in an arch ; they go from right to left on the pancreas, and from their convexity arise numerous anterior and posterior branches which penetrate from below upward into the pancreas.

2d. More to the left, five or six short gastric arteries arise (A. gastrica breves, s. fundi ventriculi). These almost always make a part of the numerous branches into winch the trunk of the splenic artery divides before entering the spleen.

These vessels retrograde toward the left large extremity of the stomach and communicate on its two faces, by numerous anastomoses, with the coronary and right gastro-epiploic arteries.

We observe a lower branch, which is large ; this is the left, gastroepiploic artery (A. gaslrica , s. coronaria sinistra inferior , gastro-epiploica sinistra) ; this descends along the great curvature of the stomach, usually anastomoses very evidently with the right gastro-epi

29G


DESCRIPTIVE ANATOMY.


ploie artery, and gives off large branches, the left epiploic arteries, to the large epiploon.

II. SUPERIOR MESENTERIC ARTERY.

§ 1452. The superior mesenteric artery {Jl. mesaraica , s. mesenterica superior ) is generally a little and often considerably larger than the cœliac artery, when the latter arises partly from the aorta or from the superior mesenteric artery, and generally comes from the trunk of the aorta directly below the cœliac trunk. It not unfrequently arises with it by a common trunk, which is sometimes nearly an inch long,(l) — a curious arrangement, as it resembles the formation of the tortoise.

The artery is covered first by the pancreas, and descends perpendicularly behind it on the lower part of the duodenum. It passes between the two layers of the mesentery and near its centre describes a considerable curve, the convexity of which looks forward and downward to the left while its concavity is turned to the right backward and upward. The centre and upper part of this curve is much farther from the small intestine than its lower portion ; it gradually diminishes and terminates on the right and downward in the right lumbar region.

All the constant branches of the superior mesenteric artery arise from this curve, which furnishes blood to a part of the pancreas, to all the small and most of the large intestine, especially to its right and transverse portions. The first branches go to the pancreas and to the duodenum ; the next go to the large intestine ; and the inferior to the small intestine. The first ansstomose with the hepatic artery, more rarely also with the coronary artery of the stomach. (2)

The arteries of the small intestine {Jl. intestinales ), which come from the convexity of the curve of the superior mesenteric artery, deserve to be mentioned before the others, (3) because the first of them arises higher than those which come from the concavity, and the study of the latter naturally leads to that of the branches which come from the inferior mesenteric artery.

The superior intestinal arteries are usually the longest ; the first is however a little shorter than the following, but the last or the lowest are shorter than the others and also the smallest.

We generally number from sixteen to twenty ; but we must reduce this number to ten or eleven, as it is more correct to consider the lowest, not as distinct trunks, but as secondary branches of the last branch,


(1) Haller considers this arrangement as a rare anomaly, because he has observed it only once; ( Ic . anat ., part viii. p. 35, No. 11). We however think it more common, for we have seen it five times, although we did not look for it particularly in the cadavers we examined.

(2) Barclay, loc. cit., p. 182.

(3) This method has been followed correctly by Mayer ( Ang ., p. 170), and Monro ( Outlines , p. 335); but not by Murray (p. 68), Scemmerring (p. 267), and Bichat (p. 267).


ANGEIOLOGY.


297


which in going from left to right and from below upward anastomoses with the last of the branches which arise from the concavity.

If we follow the usual method, the intestinal arteries are almost always more than twenty in number, and the last eight or nine are extremely small and short.

These arteries dimmish from above downward in respect to their diameter ; we however find among the largest some which are very small, although they also arise from the trunk of the mesenteric artery.

They all proceed between the two folds, of the mesentery to the intestine, distributing in their progress numerous branches to this membrane and also to the mesenteric glands. They usually divide into an upper and a lower branch. This division occurs sooner or later, in proportion as the branches are shorter or longer. These branches anastomose with the opposite branches of the adjacent arteries and form a large arch, composed of as many smaller arches as there are intestinal arteries ; the convexity of this arch always looks toward the concavity of the small intestine. The two branches do not suddenly unite, but anastomose at a proportionally short distance from the intestinal canal.

Numerous secondary ramifications arise from the convexity of these arches ; these are very compactly situated and very frequently anastomose. Hence results a much more extensive external arch, composed of a still greater number of small arches, whence arise numerous ternary branches. These also bifurcate two or three times, and anastomose in the same manner, at least where the intestinal arteries are larger.

These vessels represent by their division a very coarse net.

Finally, from the external surface of this net arise numerous arterioles, which are divided into an anterior and a posterior series, which go to the intestinal canal and are distributed on its internal membrane after still more subdivisions and anastomoses.

â–  A minute description of their distribution in the intestine will be given after that of the intestinal canal more properly than in this place.

§ 1453. From the concavity of the curve of the superior mesenteric artery, nearly opposite the place where the third, fourth, fifth, and sixth intestinal arteries arise, and about an inch from each other, are constantly given off at least two, and almost as often or at least not very unfrequently three branches, which belong exclusively to the colon, particularly to its right portion; these may be called the right colic arteries { Jl. colicæ dextrœ). Of these branches the centre is usually smaller than the other two, and generally it arises nearer the superior.

§ 1454. The lowest, which goes to the right outward and downward, is called the inferior right colic or the ilco-colic artery {Jl. colica inferior dextra , ileo-colica). Some distance from its origin it sends downward a branch, which anastomoses with that which we have considered as the last intestinal artery and which is generally regarded as the trunk of the superior mesenteric artery, uniting with this artery a little before it terminates, partly also proceeds as the artery of the cœcal appendix

Vol. II. 38


DESCRIPTIVE ANATOMY.


298

( A.appendicalis ) to the vermiform appendage of the cæcum, along which it reascends to its extremity, giving off from its convexity a great number of branches, which arise at acute angles.

Jt afterwards immediately divides into an ascending and a descending branch.

The descending branch, the cœcal artery (Jl. cœcalis), sends a large anastomosing ramuscule to the last intestinal artery or to the extremity of the curve of the superior mesenteric artery, and afterwards divides into two other secondary branches, the anterior and the posterior cœcal artery, which are distributed in the corresponding parts of the cæcum and anastomose with the artery of the cœcal appendix.

The ascending or anastomosing branch (R. ascendens , s. anaslomoticus) ascends at a short distance from the concave part of the intestinal canal along the ascending colon, to which it gives off numerous branches, not however equal in number to those of the intestinal arteries, which also anastomose less frequently. These branches divide near the colon into minuscules, forming an anterior and a posterior series, all of which are distributed to the parietes of this intestine.

§ 1455. The middle right colic artery {Jl. colica dextra media, colica, dextra , colica dextra inferior ) is always the smallest of the three branches which arise from the concavity of the curve of the mesenteric artery, and often comes from the superior. Sometimes but very rarely it is given off by the inferior right colic artery.(l) It usually commences very near the superior colic artery.

When it. is given off by the latter, it generally arises at the place where it anastomoses, when it comes from the mesenteric artery, with the superior colic artery by a short but very large branch ; so that when it forms a distinct trunk we should consider it as an anastomosing branch between the superior right colic artery and the trunk of the superior mesenteric artery.

When it is a branch of the superior mesenteric artery, it divides some" distance from its origin into a superior and an inferior branch.

The superior ascending branch is much shorter and anastomoses with a similar branch from the superior right colic artery.

The inferior descending branch is much larger, goes along the concavity of the ascending colon, and anastomoses by a large arch with the ascending branch of the inferior right colic artery.

This artery supplies the middle part of the ascending colon with blood.

§ 1456. The superior right colic artery {Jl. colica superior dextra , colica media, s. anastomotica dextra ) generally arises some inches below

(1) Bichat seems to doubt this fact, but wrongly. He says that the inferior colic artery is constantly distinct. Murray and Mayer do not mention it, although they very correctly state that the two superior right colic arteries not unfrcquently form one trunk. Sabatier and SÅ“mmerring are more correct in saying that the two inferior right colic arteries rarely arise together. Others, as Portal and Monro, mention only the cases where the three arteries form three distinct trunks.


ÂNGEIOLOGY.


299


the origin of the trunk and as high as the transverse vnesn-colon. It afterward enters between the two layers of the peritoneum, goes directly forward toward the centre of the transverse colon, and divides into a right and a left branch.

The right branch is generally a little smaller than the other, is also shorter, and anastomoses with the ascending branch of the middle right colic artery, which it sometimes replaces entirely (§ 1455).

The left branch ( R . anastomolicus magnus) passes behind the left and largest portion of the transverse colon, communicates with the ascending branch of the left colic artery given off by the inferior mesenteric artery, and forms with it the largest anastomosis found in the adult. This anastomosis is seldom deficient.

This artery is distributed to the upper part of the ascending, and to the central and right portions of the transverse colon.

§ 1457. One branch of the superior mesenteric artery, which exists only in the early periods of life, is the omphalo-mesenteric artery (A. omphalo-mesaraica ), which generally arises from this trunk, but in no determinate place ; this artery, accompanied by the veins of the same name, leaves the mesentery, passes on the lower part of the small intestine, arrives at the umbilicus, comes from the abdomen with the intestine, enters into the umbilical sheath before the end of the second month of pregnancy, and extends to the umbilical vesicle, and distributes its ramifications on its surface. This branch constantly exists until the end of the second month, after which it is almost always obliterated and is visible only in the mesentery and near the umbilicus. Sometimes it continues, always preserving rather a large caliber, and extends with its accompanying vein to the umbilical ring or even into the cord. Sometimes it is obliterated, but extends from the intestine to the umbilicus. These two cases occur principally when the intestinal canal, either alone or with other organs, is arrested at one of the first degrees through which it passes successively in its formation. The omphalo-mesenteric artery is undoubtedly the largest of those in the fetus.

in. INFERIOR MESENTERIC ARTERY.

§ 1458. The inferior mesenteric artery {-A. mesaraica, s. mesenterica inferior ) comes from the aorta, generally some inches lower than the preceding, and usually about an inch above the bifurcation of the trunk of the aorta where the two primitive iliac arteries arise.

The only exceptions are when several renal arteries existing, one of them arises very low and the mesenteric artery is constantly given off from the aorta above the latter ; its description however should precede theirs, because it. comes from the anterior part of the trunk of the aorta, and because it is distributed to the intestinal canal, as are all the other arteries which arise in like manner from the anterior side of the abdominal aorta.


300


DESCRIPTIVE ANATOMY.


Still more rarely it comes from the primitive iliac artery,(l) which happens when the aorta bifurcates higher than usual.

It is always a little smaller than the renal arteries, proceeds obliquely to the left and upward under the peritoneum, penetrates immediately between the layers of the iliac meso-colon, and divides into several branches, which belong only to the left portion of the colon and to the rectum, the upper of which may be called the left colic arteries (A. colictz sinislrœ), to distinguish them from the right (§ 1456) which arise from the superior mesenteric artery, while the lower go to the rectum and are called the upper hemorrhoidal arteries (A. hcmorrhoideœ superior es).

This artery is rarely deficient(2), a remarkable anomaly, which resembles the normal formation of many animals, viz. birds and reptiles, in which the posterior mesenteric artery gradually diminishes and entirely disappears.

§ 1459. The left colic arteries (A. coliccc. sinislrœ) arise from the upper convex part of the inferior mesenteric artery. We sometimes find two or three, a superior, middle, and an inferior. The middle is sometimes blended with the superior and sometimes with the inferior. The first case is more common.

The superior left colic artery (A. colica sinistra superior, anaslomotica sinistra ), generally the larger, proceeds along the descending colon and divides into two branches. This division occurs sometimes immediately, when it gives off the middle colic artery, sometimes later, when this arises separately from the mesenteric artery or by a common trunk with the inferior.

In the second case one branch goes to the right, the other to the left side. The latter anastomoses with the left branch of the superior right mesenteric artery, behind the left portion of the transverse colon, and thus forms a large arch ( arcus anastomolicus magnus ), (§ 1456) to produce which however it but slightly contributes. This anastomoses, in front of the upper part of the descending colon, with the ascending branch of the middle left colic artery.

The middle left colic artery (A. colica sinistra media) sometimes forms the lower branch of the preceding ; and then arises from it very early, but more frequently is a distinct trunk, which soon after divides into two branches, the larger of which ascends along the left colon, and anastomoses with the descending branch of the superior left colic artery ; and the inferior communicates with the ascending branch of the inferior left colic artery.

The inferior left colic artery (A. colica sinistra inferior), which is distributed to the lower part of the descending colon, divides still sooner into two branches, which anastomose, the ascending with the descending branch of the middle left colic artery, and the descending with the ascending branch of the superior hemorrhoidal artery.

(1) Petsclie, Sylt, obs.; in Haller, Coll.diss., vol. vi. p. 761.

(2) Fleischmann, Leichenöffnungen, 1815, p. 239.


ANGEIOLOGY.


301


§ 1460. The superior hemorrhoidal artery {A. hemorrhoidea superior, s. interna ) arises from the concavity of the curve described by the inferior mesenteric artery. It would then be more correct to consider it as the inferior of the two branches, into which this artery often divides, and the upper of which furnishes the left colic arteries.

It goes to the right, and descends behind the rectum, distributing its branches to most of this intestine. It usually divides into two branches, the upper of which is smaller, and the lower larger, and is the continuation of the trunk. Each branch immediately divides, although at some distance from the rectum, into a right and left, which open together downward and beside each other by considerable anastomoses, and are distributed to the rectum, where their branches usually communicate with those of the vesical and uterine arteries.

We shall mention the difference in the arrangement of the arteries of the small, and those of the large, intestine, when treating of the intestinal canal.

II. LATERAL BRANCHES.

§ 1461. The lateral branches of the abdominal aorta are the middle capsular, the renal , and the spermatic arteries.

I. MIDDLE CAPSULAR ARTERIES.

§ 1462. The middle capsular arteries (A. capsulares mediae) are one, two, and sometimes even three, in number, and arise from the aorta very near each other, usually above, sometimes below, and a little in front of the renal arteries. In some subjects they come from the cceliac or from the renal arteries. They go to the right and left, passing on the bodies of the vertebra, and arrive from below upward on the posterior face of the renal capsules, but at the same time they send branches to the pillars of the diaphragm, and to the lymphatic glands in the lumbar region.

II. RENAL ARTERIES.

§ 1463. The renal or emulgent arteries (./2. renales s. emulgenles) come entirely from the side of the aorta, directly below the superior mesenteric artery. They arise at a right or at an almost right angle ; they proceed from before backward and from within outward, directly on the lateral faces of the bodies of the first or second lumbar vertebra, and, arrived at the kidney, penetrate into its fissure after dividing, most frequently near this organ, into several and generally into three branches, which also subdivide before entering its substance.

They arise almost opposite each other ; the right however is a little lower than the left, because the kidney of this side is lower than that of the other. To this law however there are exceptions. We remark


302


DESCRIPTIVE ANATOMY


particularly that when the right renal artery is double, the superior usually arises a little higher than the single renal artery of the left side.

These arteries are very large, but not, as Bichat says, the largest in the abdomen, since they are smaller than the cceliac or the superior mesenteric artery.

§ 1464. The renal arteries present many anomalies. The most usual afFecl their number. We generally find only one renal artery on each side. This number however is frequently, in fact often, increased by reducing the branches into distinct trunks, which arise directly from the aorta. The transition to this arrangement is marked by that where the single renal artery early divides into branches : this early division is not unfrequent, and often occurs only on one side ; the renal artery of the opposite side being already divided into several separate trunks.

This anomaly of the renal arteries differs,

1st. In the conditions of its occurrence; 2d, in the number of divisions it produces ; 3d, in its occurrence on one or both sides ; 4th, in its being more frequent on one side than on the other ; 5th, in the proportional size of the separate trunks ; 6th, in their place of origin ; 7th, in their insertion ; 8th, in their relation with the renal veins.

1st. The conditions in which the number of the renal arteries is increased are,

a. An unusual size of the kidneys.

b. Their unusual length, although their size is not much increased. In this case their central portion is often strangulated.

c. The union of the two kidneys.

d. Their unusually low situation in the pelvis.

2d. In respect to number. The renal arteries are increased by one more commonly than by many.

Sometimes however there are three, four, and even five on one side.

3d. In regard to the simultaneous existence of several renal arteries on both sides at once, we remark generally that when there are not more than two, the anomaly occurs on one side as frequently as on both. When however this increase is more than two, it is rarely confined to a single side, although it very seldom occurs on both sides in the same degree. This rule however is not general, since four renal arteries sometimes exist on one side and only one on the other.

4th. The anomaly does not seem to affect one side of the body more than the other. This remark is the result of our own observations ; it however is confirmed by the difference in the assertion of authors on this subject. Some say that the anomaly is more frequent on the left and others on the right side.

5th. The anomaly is the least possible when one of the two renal arteries is much smaller than the other. The larger then is generally but not always the upper; it forms the normal trunk. In fact the


ANGErOLOGY.


303


supernumerary renal arteries not unfrequéntly have the same caliber, each of them, considered separately, being a little smaller than the normal artery, except when one kidney is larger than the other.

6th. The supernumerary renal arteries also vary much in their origins. The nearest to the normal formation is where the second renal artery arises directly at the side of the normal artery ; but they are frequently very distant from each other, so that one or some of them not only arise from the aorta, below the inferior mesenteric artery, but also come from the primitive iliac or even from the hypogastric artery ; the last two cases however usually occur only when the kidneys are blended together or are situated very low. But if we except those cases where the kidney is situated very low, one renal artery generally arises from the usual place, however remote may be the origin of the others.

When more than two renal arteries exist, one generally arises very far from the rest. Sometimes they are situated at equal distances from each other. Sometimes also when four occur two of them arise very high, and two very low.

7th. The place of insertion is more abnormal, the lower the origin of the renal arteries, and the greater the anomaly in the form and situation of the kidneys. If the arteries are given off very low, although the situation of the kidneys is normal, they frequently do not enter its fissure, but are inserted at its lower extremity. If the kidney is situated very low, the vessels usually converge fiom all sides to enter it.

8th. The relation between the renal arteries on one side, and the emulgent veins and the vena-cava on the other, may be regarded in two points of view :

1st. In regard to their simultaneousness and frequency. A series of careful observations permit us to establish as a principle that the veins divide much more rarely than the arteries, and consequently the veins are not always abnormal, in this respect, when the arteries are, although this is somewhat common, even when the arteries exist, in regard to these two orders of vessels at the same time ; the number of renal arteries nevertheless frequently exceeds that of the emulgent veins, although sometimes, but rarely, the veins alone are abnormal.

2d. Usually, particularly when more than two renal arteries exist, the relation of the situation with the veins is changed in this respect, that one or both of them pass before and not behind the vena-cava inferior to go to the kidney. One easily perceives that this rule can apply only to the renal arteries of the right side.

The two renal arteries much more rarely arise from the anterior face of the aorta by a common trunk which, in the only case of this anomaly known to us, was inserted very near the mesenteric artery.

Other anomalies relate to the side of the vascular system whence the renal vessels arise. Each renal artèry generally goes to the kidney of the same side. The only exception to this rule is when the kidneys exist in the pelvis ; one of the renal arteries then not


304


DESCRIPTIVE ANATOMY.


unfrequently arises from the primitive iliac, or from the hypogastric artery of the opposite side.

§ 1465. Beside these slight and inconstant differences between the renal arteries of the two sides, in respect to the height at which they arise, they are constantly distinguished from each other by their length ; that of the right side being longer than the other, and more so because the aorta is situated more to the left. In its course to the kidneys it usually passes behind, but not unfrequently before the ascending vena-cava.

The renal arteries belong particularly to the kidneys and enter almost wholly into the fissure. Proceeding however they always give several greater or less branches. These are,

1st. The inferior capsular artery (./?. suprarenalis inferior) almost constantly arises from the renal artery, or at least comes very rarely from the aorta itself with the middle capsular arteries. This artery is even sometimes double, since, beside the usual artery, that which directly arises from the origin of the renal artery, a smaller one exists, which comes from one of its branches.

This inferior capsular artery is not unfrequently very large. In this case it gives off branches to the lumbar portion of the diaphragm, and sometimes the whole inferior diaphragmatic artery comes from it.

2d. The branches which go to the pelves of the kidneys and to the ureters.

3d. Rarely, and most generally on the left, and even then usually only where several renal arteries exist, the spermatic artery, which in this case constantly arises from the inferior renal artery. We have however satisfied ourselves that when the renal artery divides into several branches, the spermatic artery is by no means always inserted in one of the latter.

4th. Some branches to the renal capsule. These ramifications enter into the substance of the kidney, and there are likewise some small branches which go from the substance of the kidney to the capsule.

5th. More rarely the right renal artery sends a branch to the lower part of the liver.


HI. SPERMATIC ARTERIES.

§ 1466. The spermatic arteries (.4. séminales, s. sp er malic ce) are usually single but not unfrequently double. They generally arise a little but sometimes far above the renal artery. They rarely originate opposite each other ; one is frequently detached much higher than the other and much more before it, and most generally before the middle capsular arteries, making with the aorta an acute angle. Frequently also the spermatic artery on one side (§ 1464) arises from the renal, or from the inferior or middle capsular artery. More rarely it arises from the lumbar, from the external iliac, from the hypogastric, or even from the epigastric artery of its side. It generally extends vertically


ANGEIOLOG Y.


305


downward, but sometimes also it turns on the renal vessels before assuming its downward and outward direction, which it follows and keeps it directly behind the peritoneum, and before the ureter, which it crosses. That of the right side also passes before the vena cava inferior.

The spermatic artery is much shorter in the female than in the male, since it does not leave the abdomen, and is distributed to the ovaries, and also to the. Fallopian tubes, to the round ligaments, and to the upper part of the uterus, communicating with the. uterine arteries by numerous anastomoses.

In the male on the contrary it leaves the abdomen through the inguinal ring, forms with its corresponding vein and the lower part of the vas deferens the spermatic cord, gives branches to the common membrane of the cord and testicle, and is distributed principally in the latter organ.

In its course it gives upward branches to the duodenum, the liver, the transverse meso-colon, the renal capsules, the lymphatic glands in the lumbar region, and to the ureter, and frequently anastomoses with the branches of the mesenteric and lumbar arteries.

III. POSTERIOR BRANCHES. LUMBAR ARTERIES.

§ 1467. The lumbar arteries (A. lumbales ) are the posterior rather than the lateral branches of the abdominal aorta, since they usually arise nearer the centre of the posterior face than the sides of this artery. In this respect there are different degrees between the entire lateral insertion of these arteries and the origin of those which correspond on the right and on the left by a common median trunk often several lines in length, before dividing into the right and left lumbar arteries.(l) All the lumbar arteries of the same subject are arranged in this respect after the same type.

These arteries correspond to the intercostal arteries and are also formed on the same level as they, both generally and particularly. But they are usually larger. Soon after arising, they go outward in the groove of the vertebrae, between the fasciculi of the psoas magnus muscle, to which they give numerous branches, as also to the quadratus lumborum and lumbar vertebrae, gradually arrive at the transverse processes of the latter, and always divide at their base, opposite the intervertebral foramina, into a posterior or dorsal and an anterior or lumbar branch.

(1) Scemmerring (p. 277), who follows Murray (p. 75) in this, does not mention that the right and left lumbar arteries arise by a common trunk, but speaks only of the fourth. Others, as Mayer, Boyer, Sabatier, Hildebrandt, and Monro, do not speak of it at all. Portal is more correct when he states in a general manner that the synonymous lumbar arteries of the two sides sometimes arise by a common trunk. We have found that this anomaly is not unfrequent, and that, as we have already remarked, it usually affects all the lumbar arteries. Its frequency, compared with the proportional rarity of a similar arrangement in the intercostal arteries, is worthy of remark, as it coincides with the less marked development of the abdominal parietes.

Vol. II. 39


306


descriptive anatomy.


The 'posterior or dorsal branch (II. dorsalis ) is usually the smaller, and gives off a branch called the spinal lumbar artery (Jl. spinalis lumbalis ), which passes into the spinal canal through the intervertebral foramen, is distributed on the dura-mater and the pia-mater, descends to the cauda equina, anastomoses with the synonymous branch of the opposite side and also with the anterior spinal artery, and is distributed also to the lower part of the muscles of the back.

The anterior or lumbar branch ( R. lumbaris ) -goes forward between the broad abdominal muscles, within which it anastomoses with the branches of the epigastric artery.

There are usually as many lumbar arteries as there are lumbar vertebrae, viz. live. In general however there are not five which arise by separate trunks, but many of them, especially the two or three lower ones, often arise by a common trunk, which soon bifurcates. Sometimes this union of the two lumbar arteries on the same side, situated one above the other, coincides with that of the synonymous branches on the right and left, on one or on both sides, which we have already mentioned.

Most generally even only the four superior lumbar arteries arise from the aorta, and the fifth is given off by the anterior branch of the fourth.

Thus we usually observe at most but four aortic lumbar arteries.(l)

Finally, there is no symmetry in this respect between the lumbar arteries of the two sides of the body.

§ 1468. The first lumbar artery is frequently deficient, and in most subjects it arises from a trunk in common with the last intercostal artery or it is replaced by .the branches of the latter. It is always small, so that when this arrangement exists and while at the same time the inferior lumbar artery arises by a secondary branch, which is much more common, we observe only three of these arteries.

Even when it is separated from the last intercostal artery, it proceeds a short distance below the lower edge of the last rib, under the insertion of the diaphragm. Sometimes its anterior branch curves between the transversalis abdominis muscle and the peritoneum along which it descends.

The second lumbar artery usually arises between the second and the third lumbar vertebra ; it goes first a little from below upward, then from before backward, and from within outward in the groove of the second vertebra. Its anterior branch is distributed principally in the quadratus lumborum and transversalis abdominis muscle.

The third lumbar artery arises between the third and fourth lumbar vertebrae, and descends on the first of these two bones. Its anterior branch is very large and passes between the psoas magnus and the

(1) This assertion cannot be disputed, when we speak of the trunks which arise directly from the aorta. Boyer (p. 127) and Portal (p. 290) have adopted it. But it is very incorrect to consider, with Haller and Sabatier, the inferior intercostal as the first lumbar artery, and consequently to admit six lumbar arteries, although the first lumbar not unfrequently arises from the last intercostal artery, or is replaced by its branches.


ANGEIOLOGY.


307


quadra tu s lumborum muscles, to which it gives branches, descends toward the anterior part of the crest of the ilium, and directly above this place goes through the abdominal muscles to the glutæi, where it ramifies and anastomoses with the gluteal artery.

The fourth lumbar artery arises on the fourth lumbar vertebra, or between the fourth and the fifth: Its anterior branch passes before the

quadratus lumborum muscle, proceeds forward on the crest of the ilium, through the muscles of the back, to enter, like the preceding, into the glutæi muscles.

The fifth lumbar artery is a branch of the sacral artery ; we shall therefore describe it when speaking of the latter.


CHAPTER V.

ARTERIES OF THE PELVIS AND THE LOWER EXTREMITIES.

§ 1469. The aorta usually divides on the fourth lumbar vertebra, or between the fourth and fifth, into two or three trunks. Two are much larger and more constant, and are the arteries of the lower extremities (J3. crurales , Barclay) being called at their origin the primitive iliac arteries ; they separate from each other at an acute angle and go outward. The third trunk is much smaller and inconstant, and is called the middle sacral artery.

I. MIDDLE SACRAL ARTERY.

§ 1470. The middle sacral artery (A. sacra , s. sacralis media), although very small, being no larger than a lumbar artery, is very remarkable, first, because from its situation and distribution it in fact represents the continuation and the end of the trunk of the aorta ; secondly, because it adds to the analogy already existing between the distribution of the upper end and that of the lower part of the aorta.

When it arises from the aorta, it comes from its posterior side, directly above the origin of the two primitive iliac arteries. It is not unfrequently given off by the latter, especially that of the left side, from which it generally then arises very high, directly below its origin.

It descends more or less exactly on the centre of the anterior face of the body of the last lumbar vertebra, and of those of all the false vertebrae of the sacrum and coccyx, directly upon the surface of these bones, and curves frequently.

It gives off only lateral branches.

The first and largest is usually the fifth or the last left lumbar artery (§ 1469), which is sometimes larger than the continuation of the trunk, and then the middle sacral artery seems to arise from the inferior lumbar artery.


308


DESCRIPTIVE ANATOMY.


This branch, like all the lumbar arteries, goes backward and outward. It divides, before the intervertebral foramen, between the fifth lumbar vertebra and the first false vertebra of the sacrum, into two branches, a posterior or dorsal , and an anterior , which is much larger. The first is distributed as usual ; it goes outward, under the psoas magnus muscle, and sometimes, when the fourth lumbar artery does not descend so low as usual, it proceeds on the crest of the ilium, and goes to the quadratus lumborum muscle, through which it passes into the broad abdominal, and also into the glutæi muscles ; sometimes when these branches arise from the fourth lumbar artery, and the ilio lumbar artery is not as much developed, it penetrates into the psoas magnus and the iliacus muscles.

Two transverse branches more or less tortuous than usually arise from the lateral parts of the middle sacral artery on each false vertebra of the sacrum ; these go outward, give numerous ramifications to the periosteum and to the substance of the sacrum, anastomose with the branches of the lateral sacral arteries which go to meet them, penetrate with them into the spinal canal, through the anterior sacral foramina, then emerge from the posterior sacral foramina, and are expanded in the inferior part of the multifidus spinæ muscle.

The middle sacral artery finally terminates at the end of the coccyx, in the lower extremity of the rectum and in the fat which surrounds this intestine.

This artery is not always single ; it sometimes divides into two branches, which anastomose with each other and with the lateral sacral arteries.

There is constantly an inverse relation between the middle and the lateral sacral arteries in respect to their development, when one or the other is unusually large.

II. PRIMITIVE ILIAC ARTERIES.

§ 1471. The primitive iliac arteries (A. iliac ce. primitives, s. communes , s. pelvi-crurales , s. crurales lumbales, s. cruri-lumbares ) separate at an acute angle, go outward, downward, and forward, on the last two lumbar vertebræ, and on the first false vertebra of the sacrum, the right after passing on the left primitive iliac vein, the left proceeding directly before and at the same time on the outside of the synonymous vein, and divide as high as the sacro-iliac symphyses, into two considerable trunks, the hijpogastric and the external iliac artery.

The primitive iliac arteries usually have about the same .length and caliber on both sides. The right however is most generally a little higher than the left, because the aorta occupies the left side of the vertebral column as the primitive iliac arteries, nevertheless, both arise at the same height. The left descends a little more vertically than the right. Those authors who mention some difference between


ANGEIOLOGY,


309


the two primitive iliac arteries, especially Mayer, and after him SÅ“mmerring, indicate only this relation, which in fact is most frequently observed. These anatomists also assert that the right primitive iliac artery is a little smaller than the left.

We have never observed this last difference, but rather the contrary. The first in fact generally occurs, although we have sometimes but very rarely remarked an inverse arrangement, and even in a much more evident manner, although the aorta ascend as usual on the left of the vertebral column.

In one case of this kind now before us the right primitive iliac artery is nearly a third shorter than the left, and bifurcates between the fourth and fifth lumbar vertebræ.

The most usual arrangement is remarkable, because it adds still more to the analogy between the upper and lower halves of the body, since the greater length of the right primitive iliac artery resembles the innominata of the right side, arid that of the left side the origins of the left carotid and subclavian arteries by two distinct trunks. The latter arrangement however is only indicated at the lower extremity of the aorta, where a perfect repetition has not yet been found, at least to our knowledge.

The rarest arrangement corresponds to the inversion of the right and left trunks of the arch of the aorta, which has been sometimes observed, although the aorta presented no other anomalies.

The primitive iliac arteries usually give off in their course small branches, which go to the psoas and the iliacus muscles, the ureters, the vena-cava, and the lymphatic glands of this region. They rarely give off a part or the whole of the ileo lumbar artery, and still more rarely they supply a renal or a spermatic artery.


ARTICLE FIRST.

I. HYPOGASTRIC ARTERY.

§ 1472. The hypogastric artery (A. hypogastrica s. iliaca interna, s. posterior pelvica, s. hypoiliaca) descends a little forward and inward, soon penetrates, almost vertically, into the cavity of the pelvis, where it always divides, near its origin, into several branches, which vary in size, and are not always arranged exactly in the same manner, and do not arise from it constantly. It thus distributes the blood to all the parts within the pelvis, to its parietes, and to the muscles which surround it. It is always more or less evidently divided into two branches, a posterior and an anterior.

§ 1473. The posterior branch gives constantly the gluteal, the ileo lumbar, the lateral sacral , and the obturator arteries. From the anterior arise the ischiatic , the umbilical , and the internal pudic arte

310


DESCRIPTIVE ANATOMY.


ries, which usually give off the middle hemorrhoidal , the uterine , the vaginal, and the vesical arteries. Frequently however the secondary branches, particularly those of the posterior branch, arise from the 'trunk of the hypogastric artery, or from the anterior branch ; the first is true, particularly of the ileo-lumbar, and the second of the obturator artery ; the two latter not unfrequently do not arise from the hypogastric artery but very far from the usual place, either from the primitive iliac or from the crural artery.

I. IHO-LUMBAR ARTERY.

§ 1474. The ileo-lumbar artery (A. ileo-lumhalis ) is usually the first, which arises from the posterior branch of the hypogastric artery, and is frequently divided into several, sometimes into three or four, trunks, which come from different points. Not unfrequently it partially or wholly arises from the primitive iliac, from the trunk of the hypogastric artery, from the anterior branch of the latter, or from the crural artery, or, as happens particularly on the left side, from the middle sacral artery, or, finally, it forms a common trunk with the lastl umbar artery. Its volume is by no means always the same.

It goes almost horizontally outward and backward, and soon divides, usually near the sacro-iliac symphysis, into an ascending and a descending branch.

The ascending branch ascends between the psoas and iliacus muscles, to which it sends ramifications, anastomoses with the inferior lumbar artery, which it sometimes entirely replaces, or which in other cases takes its place, and either alone or with the latter, sends branches into the spinal canal through the last intervertebral foramen of the lumbar region.

The inferior branch is more or less transverse, although a little oblique from above downward ; it goes outward, and divides into superficial and deep branches.

The former are distributed on the anterior face of the psoas and iliacus muscles. The others between the latter and the os ilium, enter the muscle through its attached face, and thus penetrate into the substance of the bone through several foramina of nutrition.

All these branches proceed outward and forward, and frequently communicate with those of the circumflex iliac artery.

The anterior branches are distinct, and usually arise from the anterior branch of the hypogastric artery ; they are small, and go to the iliacus and psoas muscles. When the ilio-lumbar artery divides into two large branches it often gives off only an ascending and a descending branch ; but the superficial portion of the descending branch is frequently a part of the superior, and the anterior is formed only by the deep branches.


ANGEIOLOGY.


311


II. LATERAL SACRAL ARTERY.

§ 1475. The lateral sacral artery (A. sacra lateralis ), is perhaps more frequently double than single, and is sometimes given off by the trunk of the hypogastric or by the ileo-lumbar artery ; hr some subjects it is the first artery of the posterior branch of the hypogastric when the preceding artery arises from another point. It is rarely given off by the primitive iliac artery. It goes backward and inward and descends on the anterior face of the sacrum, before the anterior sacral foramina.

In this course it divides into internal and posterior branches.

The internal are distributed on the anterior face of the false vertebrae of the sacrum, to which they give their branches, and anastomose with the lateral branches of the middle sacral artery (§ 1470).

The posterior or external penetrate in the anterior sacral foramina and soon divide into branches, an anterior, distributed on the posterior face of the body, and a posterior, which emerges from the posterior sacral foramen, and is distributed in the lower part of the muscles of the back.

All these branches give twigs to the lumbar and sacral nerves, also to the membranes of the spinal marrow, and anastomose with the anterior spinal artery.

When the lateral sacral artery is double, the upper portion, which goes only backward, is usually separated from the lower ; but in this case it does not always come from the trunk of the hypogastric or from the ileo-lumbar artery ; it as often arises above the inferior portion, before the posterior branch of the hypogastric artery.


III. OBTURATOR ARTERY.

§ 1476. The obturator artery (A. obturatoria ) is very inconstant in its origin. It usually arises from the posterior branch of the hypogastric artery, whence it comes directly or by a trunk in common with the ileo-lumbar artery, but frequently, at least once in ten times, is given off at another part.

The general character of all these differences in. its origin is, that it arises farther outward and forward.

The anomaly is least when the obturator artery arises from the hypogastric artery above and before the place where the latter divides into an anterior and a posterior branch.

Next come the cases where it arises from the anterior branch of the hypogastric artery.

The anomaly is still greater when it arises from the primitive iliac artery. The latter gives it off either within or without the cavity of the pelvis, sometimes directly and sometimes indirectly.


312


DESCRIPTIVE ANATOMY.


It arises from different parts of the inner and outer portion of the primitive iliac artery.

Sometimes it is given off by the superficial femoral artery, two inches below Poupart’s ligament.

When it is not a direct branch of the crural artery, it arises by a trunk in common with the epigastric artery. The most usual case, which is almost as common as that where the artery arises from the hypogastric artery, is, according to our observations, as 16 : 1, in respect to its frequency with that where it arises directly from the crural artery.

The common trunk varies in length from two lines to two inches, but it is usually short and its origin is no higher or lower than usual ; in both cases however its length exceeds the rule.

But in all these anomalies, however remotely the obturator artery may arise from its usual place, it always passes on the horizontal branch of the pubis to enter into the cavity of the pelvis and be distributed as usual, and emerges from this cavity through the obturator foramen. This peculiarity is an important argument in support of the law, that when the organization presents an anomaly it always approximates as much as possible to the normal state.

Between the cases where the obturator artery arises from the hypogastric artery and where it comes from the crural artery, we find an intermediate case, where it arises from the union of two branches nearly equal in size, an anterior and a posterior, which arise, the former from the epigastric or the crural artery, the other from the hypogastric artery, and which anastomose at an acute angle.

It is. pleasant to observe that these differences are indicated in the most normal formation, since a smaller or larger anastomosing branch always passes above the horizontal branch of the pubis, extends from the obturator artery given off by the hypogastric artery to the crural or to the epigastric artery. Consequently the internal obturator artery always arises to a certain extent from an anterior and a posterior branch. When the posterior is more developed, the artery seems at first view to come principally from the hypogastric artery, while, when the anterior branch is larger than the other, we are led to conclude that the obturator artery arises from the femoral or from the epigastric artery.(l)

(1) These anomalies in the origan of the obturator artery arc common, as we have already remarked. Portal, although he asserts that the origin of this vessel is very inconstant, brings forward as proof only the cases where it arises from the trunk or from the branches of the hypogastric artery, but when describing this or the epigastric artery, he mentions those only where it arises from the latter or from the crural artery. Mayer only remarks that the obturator artery is sometimes given offby the crural or by the epigastric artery. Hildebrandt does not mention, when speaking of the obturator or of the epigastric artery, the anomaly which occurs when the first arises from the second, although this is more common than when it arises from the crural artery. He only says that it comes from the hypogastric or from the crural artery, and thus he at least indicates the frequency of the latter arrangement. Monro says that it is sometimes given oft' by the epigastric artery (p. 353). Sabatier (p. 108) and Boyer (p. 134) remark that it arises in some subjects from the epigastric or from the crural artery. Murray mentions only those cases where it arises from the epigastric artery. Haller, Scemmerring, Bichat, Hardrops, Burns, Cooper, and Monro


ANGEIOLOGY.


313


This arrangement of the obturator artery is not necessarily the same on the right and left side, any more than are the varieties of any other artery. It follows however, from our observations, that it is more common or at least as common to find both sides of the body formed after the same type as to find this type only on one side. Thus in most of the preparations before us, the obturator artery comes on both sides from the hypogastric ; in four, it arises by a trunk in common with the epigastric artery, and there are five only in which it arises from the epigastric artery on one side, and on the other, directly from the crural artery by a trunk in common with the epigastric artery.

When the obturator artery arises from the epigastric only on one side, this variety generally occurs on the left. At least our observations have shown that the cases in which it arises from the left epigastric artery are to those where it comes from the right as 10 : 1. We do not think that sex has any influence in this respect ; we have not observed that the origin of the obturator artery outward is more common in the female than in the male, as Hesselbach asserts.

§ 1477. Most commonly, when the obturator is a branch of the hypogastric artery, it goes outward and forward, directly below the upper edge of the cavity of the pelvis, gives off in its progress some inconstant ramuscules to the levator ani and obturator internus muscles, to the glands of the pelvis, and to the obturator nerve which accompanies it, passes through the upper and tendinous part of the obturator intemus muscle, at the upper part of the obturator foramen, and emerges from the

have written the best upon this artery. Haller says ( Ic.fasc . x. expl. tab. i. not. 9) : Non tarnen perpetuum est, earn arteriam a pelvis truncis nasci, cum novies viderim ex epigastrica ortam. Scemmerriug expresses himself with much exactness. This artery, he says, is not constant in its origin ; it sometimes arises from the crural and often from the epigastric artery (p. 294). Bichat also mentions the frequency of this last origin. Wardrop says he has observed it in many subjects. The details on the origin and distribution of this artery given by Burns are most correct ; they perfectly agree with our own observations. He says the obturator artery is usually regarded as a branch of the internal iliac artery, but wc have as good right to assert that it arises from the trunk or from one of the branches of the external iliac. We have often seen it come from this vessel, an inch above Poupart’s ligament. It frequently arises by a trunk in common with the epigastric artery. These details are given in his treatise on diseases of the heart. Farther (Observations on the structure of the parts contained in crural hernia ; in the Edinb. Med. and Surg. Journ., voL ii. p. 272), he says that the obturator and the epigastric arteries often arise by a common trunk ; perhaps however this arrangement may be considered as a rare anomaly, but he has observed it more than twenty times. Cooper ( 77te anatomy and surgical treatment of crural and umbilical hernia, 1807, Edinb. Med. and Surg. Journ., vol. iv. p. 231) also states, when speaking of the origin of the obturator and epigastric arteries by a common trunk, that it is not rare. Monro (Anat. of the gullet , p. 429) establishes the relation between this case and those where it does not exist as 1 : 10. Bekkers also mentions (Diss. de hernia inguinali, Paris, 1813) three cases observed by himself, in which these two vessels arose in common from the external iliac artery. We have mentioned these cases, which support our observations, because Hesselbach (Neueste anatomisch-pathologisch Untersuchungen über den Ursprung und das Fortschreiten der Leisten-und Schenckelbrüche, Wurzburg, 1815) is wrong on this subject. He maintains, which seems impossible in so distinguished an anatomist, not only that this variety is very rare but adds, that, as to his knowledge the lesion of this artery has been observed only in females, the injury of the obturator artery in the male is not to be feared.

Vol. II.


40


314


descriptive anatomy.


pelvis to be distributed to the upper and internal part of the thigh. It usually gives off also, before leaving the pelvis, a branch, which anastomoses with a corresponding branch of the opposite side on the symphysis pubis, and always gives origin to a branch, which varies in size and anastomoses with the epigastric artery above the horizontal branch of the pubis

In or directly before the obturator foramen, the obturator artery usually divides into two branches, an external and an internal.

The internal branch is smaller and passes above the obturator externus muscle, gives branches to it and also to the adductor brevis and longus, to the gracilis, to the pectineus, and to the skin of the internal part of the thigh, the scrotum or the labia pudenda, commonly anastomoses with the internal circumflex artery of the thigh, and with the external branch on the circumference of the obturator foramen, and with the external pudic artery in the scrotum and the labia pudenda.

The external branch descends deeply outward between the obturator internus and extemus muscles, gives branches to these muscles in which it sometimes terminates, is reflected from within outward on the articular capsule and the inner part of the articulation to emerge from the obturator foramen, and passing behind the quadratus femoris muscle goes transversely to the posterior part of the extremity ; then it is distributed to the quadratus femoris, to the gastrocnemii, to the adductor longus and brevis, to the upper extremity of the flexors of the leg, Anally, to the substance of the external condyle of the femur ; anastomoses with the internal branch on the circumference of the obturator foramen and with the ischiatic artery above, and within with the internal circumflex and the internal hemorrhoidal arteries.

§ 1478. The varieties in the origin of the obturator artery are very important to the surgeon. When this artery arises at the usual place from the hypogastric or from the crural artery within the pelvis, and even from the epigastric artery, but far above the crural arch, it is not exposed to be wounded in any of the common operations. But when its origin is situated very low, audit comes either from the crural artery or by a trunk in common with the epigastric artery, as it then always re-enters the pelvis over the branch of the pubis, it is exposed to wounds in the operation for crural hernia.

When the common trunk of this and the epigastric artery is short, it is generally thrown outward toward the ischium in crural hernia, so that it would be divided if the incision should be made in this directional)

When, on the contrary, this same trunk is long and the obturator artery consequently goes farther inward, it is pushed down by the crural hernia and proceeds before the neck of the tumor inward. (2)

(1) See a case of this kind figured in Monro, Morbid anatomy of the human gullet, Edinburgh, 1811, tab. xiv. fig. 1.

(2) Wardrop has figured a case of this kind (Kd.inb. Med. and Surg. Journ., vol. ii. p. 203), and points out the means of avoiding the obturator artery in this case. See


ANGEIOLOGT,


315


We must however in this case determine whether the crural hernia is situated more or less outwardly.

If an external and an internal crural hernia exist on one side, thi obturator artery sometimes passes to the inside of the external tumor, even when the common trunk of this vessel and of the epigastric artery is short, and enters the cavity of the pelvis between the two tumors. This has been observed by Burns.

If the obturator artery rises far below the usual place and from the crural artery, either directly or by a trunk in common with the epigastric artery, it generally proceeds deeply, along the pectineus muscle, on the inside of the crural vein, so that, being situated behind the tumor, in case of crural hernia it cannot be wounded in the operation.

But if it was nearer the surface, it might be situated also on the anterior face of the tumor. We have never seen this latter arrangement. Bums and Monro have observed only the first.

IV. GLUTEAL ARTERY.

§ 1479. The gluteal or posterior iliac artery (Jl. glutea, s. iliaca posterior , s. externa ), the largest artery of the posterior branch of the hypogastric artery, which may be considered as its continuation, arises very often by a trunk in common with the ischiatic artery. Sometimes it furnishes the lateral sacral, the obturator, and all the other arteries which usually come from the posterior branch of the hypogastric artery. It goes downward, forward, and outward, toward the lower part of the ossa ilia, usually sends off, in this course, branches to the iliacus inturnus muscle, to the obturator internus, to the pyriformis, to the levator ani, and to the os pubis, then emerges from the pelvis through the ischiatic notch, between the pyriformis and the gluteus minimus muscle, is reflected from below upward, penetrates between the gluteus médius and minimus muscles, and divides into numerous branches, which are distributed to the pyriformis and to the three glutei muscles and anastomose above with the epigastric, the last lumbar, and ilio-lumbar arteries, below with the ischiatic and with the external circumflex artery.

§ 1480. The anterior branch of the hypogastric artery gives off, first, the ischiatic artery, the internal pudic, and the umbilical arteries. The vesical, uterine, and vaginal arteries come from one of the latter ; sometimes also they arise by a common trunk.

V. ISCHIATIC ARTERY.

§ 1481. The ischiatic artery (Jl. ischiadica) arises separate from the internal pudic artery less frequently than by a trunk, which varies in length, in common with the latter, and often by a trunk in com Burns, Observations on the structure of the parts contained in crural hernia , in the Edinburgh Med. and Surg. Journ., vol. ii. p. 273, fig'. 1.


316


DESCRIPTIVE ANATOMY.


mon with the gluteal artery. It descends before the latter, but at the ischiatic notch it turns backward, continuing still to descend, and Emerges from the pelvis, below the pyriformis muscle.

The common trunk of the ischiatic and of the internal pudic arteries frequently does not bifurcate, except in this place, to give origin to two arteries ; and from its portion within the pelvic cavity arise branches which are distributed to the pyriformis, to the obturator internus, and to the levator ani muscles.

On emerging from the pelvis the ischiatic artery sends, to the posterior part of the ilio-femoral articulation, branches which anastomose with the circumflex arteries. It afterward goes backward, toward the gluteus maximus muscle, into which it penetrates from within outward, and within which it is almost entirely distributed.

It often gives off the middle hemorrhoidal, the uterine, the vaginal, and the vesical arteries, especially when it arises by a long trunk, in common with the internal pudic artery.

It not unfrequently gives off an inferior lateral sacral artery when the usual artery of this name does not descend very low, and is unusually small.

It constantly anastomoses by large branches, above, with the ischiatic artery, and with the circumflex arteries below, around, thecoxo-femoral articulation of the large trochanter.

VI. INTERNAL PUDIC ARTERY.

§ 1482. The internal jmclic artery (A. pudenda interna , s. communis , s. circumflexa , s. pudica pelviena, s. hœmorrhoidea externa ) descends into the pelvis, directly before the ischiatic artery, which is generally larger than it, and when it is not given off in this place or even afterward by the latter, emerges with it from the cavity of the pelvis, between the pyriformis muscle and the large sacro-sciatic ligament, between the latter and the small sacro-sciatic ligament, afterward re-enters the pelvis, where it continues to the symphysis pubis, descends along the posterior edge of the descending branch of the ischium, on its internal face, to the tuberosity of the ischium, then reascends, always on the inner side of the bene, along its ascending branch and the descending branch of the pubis, between the obturator internus and the levator ani muscles, and having come above the symphysis pubis, terminates in the external organs of generation.

Thus the pudic artery usually emerges from the pelvis through the sciatic notch, and re-enters it between the two sacro-sciatic ligaments to leave it a second time below the symphysis pubis ; but not unfrequently, especially in the male, it always continues in the cavity of the pelvis, and then, proceeding on the lower and lateral portion of the bladder, it goes forward, across the upper part of the prostate gland, where Burns remarks it may be wounded in the operation of lithotomy particularly when the summit of the prostate gland is cut.


ANGEIOLOGV,


317


It often gives off within the pelvis one or several vesical arteries, the middle hemorrhoidal, the vaginal, or the uterine, and even the obtm rator arteries. It also sends smaller branches to the internal parts of the genital and urinary apparatus. In its course along the descending branch of the ischium, besides several small branches which go to the bone, to the obturator internus muscle, to the upper extremity of the flexor muscles of the thigh, to the lower part of the rectum, and to the sphincter ani, it gives off others also, of which the principal are,

1st. A considerable branch which goes outward, between the large trochanter and the ischium, divides into several branches, descends on the neck of the femur and the capsule of the ilio-femoral articulation, between the obturator internus and externus muscles, gives ramuscules to these muscles, and also to the quadratus femoris and to the gemelli muscles, and anastomoses with the circumflex arteries.

2d. One or more rather large internal branches, which go to the inferior part of the rectum, also to the anus, and form the external or inferior hemorrhoidal artery (A. hcemorrhoidea externa , s. inferior).

A little above the tuberosity of the ischium, the internal pudic artery divides into two branches, an internal transverse, and an external anterior ascending branch.

The internal branch, the perineal artery ( R . interims , s. transversus , s. superficialis, arteria perinÅ“a , s. transversa perinÅ“i) is smaller than the external. It goes inward and a little forward along the transversalis perinei muscle, usually between it and the skin, distributes branches to these parts, and also to the other muscles of the penis, and to the constrictor vaginae in the female ; gives some branches to the lower part of the rectum, and to the sphincter ani, which are termed the external or inferior hemorrhoidal arteries (A. hÅ“morrhoidales inferiores, s. externes ,) and sends others also to the skin of the perineum, labia pudenda, and scrotum.

The external , anterior, superior, or deep branch ( R . anterior, s. superior, s. profundus , s. pudendus) is called the artery of the penis (A. penis) in the male, and the artery of the clitoris {A. clitoridea) in the female. When the internal pudic artery gives off considerable branches within the pelvis, this artery not unfrequently arises mostly from the other adjacent branches' of the hypogastric artery, especially from the obturator artery, less frequently from the external iliac artery, particularly from an external pudic artery, an anomaly which is indicated in the normal state by the more or less manifest anastomoses between the internal and the external pudic arteries.

This artery is much larger in the male than in the female on account of the greater proportional size of the parts to which it is distributed.

In both sexes it proceeds from below upward, around the inner face of the pubis and ischium, between the bone and the corpus cavernosum of the penis and clitoris, and distributes branches to the vagina and prostate gland, the labia pudenda, and the scrotum, finally to the clitoris and the penis, which branches are arranged after the same type.


31S


DESCRIPTIVE ANATOMY


The branches which go to the prostate gland and the scrotum in the male, to the vagina and to the labia pudenda in the female, are given oft' the first, directly above the sciatic tuberosity.

After these the trunk descends along the ischium and the pubis, covered by the erector penis ( levator penis, clitoris ), and thus comes into the triangular space below the symphysis pubis, where the roots of the cdrpus cavernosum of the penis in the male, and of the clitoris in the female unite.

In both sexes, the artery then divides into two branches, the superficial and the deep branch.

The superficial or the dorsal branch, the dorsal artery of the penis or clitoris (R. dorsalis, s. superficialis penis vel cliioridis), passes through the suspensory ligament. It is very tortuous when the penis is not erected, and proceeds under the skin at the side of the synonymous artery of the opposite side, with which it sometimes unites, after a very short course, advances thus on the back of the penis, and gives branches to its skin and its fibrous membrane, and sends off others which descend into the scrotum. At the groove behind the glans, it forms a crown around it, and finally penetrates into its substance.

The deep branch or the cavernous artery ( Jl. profunda , s. cavernosa penis, s. cliioridis) passes through the fibrous membrane of the corpus cavernosum of its side, thus penetrates into the substance of this body, and soon divides into several branches. These proceed from behind forward, along the penis, expand in the corpus cavernosum of both the penis and urethra, and frequently anastomose with those of the opposite side.

The two deep branches often unite in a single common trunk.

Sometimes the internal pudic artery terminates much sooner than we have mentioned, in the transverse perineal artery, and the dorsal artery of the penis or clitoris arises wholly or in great part from the obturator artery.

VII. UMBILICAL ARTERY.

§ 1483. The third artery of the anterior branch of the hypogastric artery, the umbilical artery ( A . umbilicalis), is before birth the continuation not only of the trunk of this artery, or even of the primitive iliac artery, but is larger than the hypogastric and femoral arteries, and is the continuation of the aorta.

At all periods of life the umbilical artery goes a little obliquely forward and inward, toward the upper part of the lateral wall of the bladder, to which it is attached by mucous tissue. Thence it proceeds along this wall, toward the posterior face of the anterior wall of the abdomen, and thus goes from behind forward and from below upward to the umbilicus.

In the fetus it is open in its whole extent, but soon after birth it is gradually obliterated after leaving the umbilicus, so that finally it


ANGEIOLOGY.


319


affords a passage to the blood only in the part between its origin and the bladder, the rest of it being changed into a full and solid ligament, enveloped by a fold of the peritoneum, and which may be generally traced to the umbilicus.

During fetal existence, the lower and anterior part of the umbilical artery which is convex, gives off not only the branches of the hypogastric artery, which we described above, but also, first, the inferior vesical, then the vaginal, next the uterine, and finally one or more superior vesical arteries, which generally are very distinct from each other. But as it is gradually obliterated, and as at the same time the lower extremities and their vessels are developed, these arteries approach each other, and seem to be in part the upper arteries of the anterior branch of the hypogastric artery.

These branches arise in the following order, which we adopt, since in following it the arteries to be described, correspond from behind forward to those already mentioned.

VIII. VESICAL ASTERIES.

§ 1484. The vesicul arteries (A. vesicates) are distinguished into inferior and superior.

The inferior are larger than the superior, and generally there is only one. They arise from the umbilical or from an anterior branch of the hypogastric artery, which is usually the internal pudic, or from the trunk of the hypogastric artery ; they go downward and forward to the lower and posterior part, and also to the neck of the bladder, the commencement of the urethra, to the prostate gland and to the vesiculæ séminales in the male, and to the lower part of the vagina in the female.

The superior are generally smaller and more numerous; they always arise from the lower part of the umbilical artery, consequently from the most anterior part or from the extremity of the hypogastric artery, and go to the middle and superior part of the bladder.

IX. MIDDLE HEMORRHOIDAL ARTERY.

§ 1485. The middle hemorrhoidal artery (A. hÅ“morrhoidea media) often follows the inferior vesical artery from below upward, and from behind forward ; but frequently also it arises lower than it, being even sometimes deficient, and is given off by the ischiatic or by the internal pudic artery. Sometimes it arises from the upper or lower hemorrhoidal arteries, with which it always anastomoses, and is distributed on the anterior face of the rectum and also on the posterior part of the bladder, where it communicates with the proper vesical arteries.


320


DESCRIPTIVE ANATOMY.


X. VAGINAL ARTERIES.

§ 1486. One or two vaginal arteries ( A . vaginalis ) usually follow the inferior vesical artery. But this artery is frequently deficient, and it is then replaced by the ramifications of the vesical, the hemorrhoidal, or the uterine arteries. Sometimes also, even when it forms a distinct branch, it does not arise in the order mentioned, but comes from some one of the arteries of the anterior or of the posterior branch of the hypogastric artery.

It goes forward, inward, and downward. Its branches are distributed to the inferior and middle regions of the lateral part of the bladder and of the vagina.


XI. UTERINE ARTERY.

§ 1487. The uterine artery (Jl. uterina) generally succeeds the vaginal artery, but it frequently varies from this order. It is however constant.

It goes inward, toward the upper part of the vagina, to which it gives off some branches, as well as to the bladder ; it then reascends in the broad ligament along the lateral wall of the uterus. In its course which is very tortuous, it gives off numerous ramifications which are also curved, to the anterior and posterior faces of the uterus. Some of these ramifications are distributed on the surface and others in the substance of this organ.

Its upper part expands by several branches in the folds of the peritoneum ; they go to the internal organs of generation, to the Fallopian tubes, and to the ovaries, where they frequently anastomose with the spermatic arteries.

§ 1488. In man, the vessels which correspond to the uterine or the vaginal arteries are small secondary branches of the vesical and of the external hemorrhoidal arteries.


ARTICLE SECOND.

EXTERNAL ILIAC ARTERY.

§ 1489. The external or anterior iliac artery (.fl. iliaca externa , s. anterior , s. cruralis iliaca , s. femoralis), from its origin, descends from within outward, on the inside of the psoas magnus muscle, sends numerous small branches to this muscle, and also to the lower part of the iliacus muscle.

It usually gives off, at a greater or less distance from the crural arch, two large branches, the epigastric artery, and the circumflex


ANGEIOLOGY.


321


iliac artery, which are very important in a pathological and surgical point of view on account of inguinal and crural hernias.

The first usually arises a little and sometimes much higher than the second, and even above the crural arch ; besides, it always comes from the inside of the iliac artery, while the other constantly arises from its outside.

1. EPIGASTRIC ARTERY.

§ 1490. The epigastric artery {A. epigastrica) is rarely a branch of the common or deep crural artery,(l) but it often arises by a trunk, in common with the obturator artery, so that we may consider it as giving off this latter(2) (§ 1476), although, for all this, its origin is not necessarily displaced and carried higher than usual. It is often given off. sometimes higher and sometimes lower, from the external iliac artery, so that the place where it arises varies to the extent of two inches, although the obturator artery is not necessarily one of its branches. (3) Thus we may consider erroneous the opinion of Hesselbach, who asserts that this artery rarely varies in its origin and in its course, (4) and also that of Mayer,(5) who, like Burns, asserts that it always arises directly below the crural arch. The latter case exists very seldom, for the epigastric artery almost always arises above Poupart’s ligament. On the contrary, the place where it detaches itself from the external iliac artery varies much, although it never comes fiom any other vessel. (6) It however generally arises directly above the crural

arch, (7) and its origin is normal when situated one inch or even two inches above this arch.(8).

(1) Monro, Morbid anatomy of the human gullet, Edinburgh, 1811, p. 426.

(2) At least we have never found in this case that the epigastric was a branch of the obturator artery, although we have olten seen both arise by a common trunk, and have now several cases of the anomaly before us. Hesselbach, ( Ueber den Orprung und das Fortschreiten der Leisten-und Schenkelbrüche, Wurtsburg, p. 17) and Bekkers ( loc . cit., p. 315), mention in fact one case where the epigastric arose from the obturator artery. But it is evidently wrong, as it follows from the description of this anomaly given by the former, in saying that the obturator artery came from the inside of the crural more than an inch above the crural arch ; since it follows from it we say that the common trunk arose, as is commonly seen in this case, from the external iliac, and not from the internal iliac, or hypogastric artery, as would be the case provided the expressions of Hesselbach weie correct. This anomaly however may sometimes occur. Monro (loc. cit., p. 427) seems to have observed it, for he says that in one preparation before him the epigastric arose from the obturator artery, and afterward went upward and inward, toward the rectus abdominus muscle.

(3) Which Hesseloach seems to think necessary.

(4) Hesselbach, loc. cit., p. 17-52.

(5) Mayer, Beschreibung der Blutgefässe des menschlichen Körpers , p. 206.

(6) Monro is very correct in saying (loc. cit., p. 254) that the epigastric artery varies much in its origin.

(7) As has been correctly stated by Bichat (loc. cit., p. 311) and Murrav, (loc. cit.. p. 89).

(8) Outlines, p. 354.

(9) According to SÅ“mmerring, lor. cit., p. 307.


Vor. II


41


DESCRIPTIVE AN ATOM V


322

When the epigastric artery arises unusually high it descends near the crural arch, sometimes very low, even below this arch, and always passes behind the commencement of the spermatic cord, above the inguinal ring, so that it is situated on the inside of this cord. There it suddenly curves and reascends vertically on the posterior face of the rectus abdominis muscle, first between this muscle and the peritoneum, then between it and the posterior layer of the sheath.

Soon after it is reflected around the spermatic cord, it gives off, directly above the inguinal ring, a constant branch, which divides into two branches ; one goes downward and backward and anastomoses with the iliac artery, the other is transverse and goes inward, proceeds along the horizontal branch of the pubis, behind the inguinal ring, and communicates with that of the opposite side. It also sends to the spermatic cord or to the round ligament of the uterus, some ramifications which penetrate to the scrotum and the labia pudenda, and anastomose below with the spermatic arteries, and above with the uterine arteries in the female. These ramifications, which go to the spermatic cord and to the round ligament of the uterus, sometimes come from the trunk of the external iliac, even above the epigastric artery, when the latter arises lower than usual. This arrangement coincides with the very high origin of the spermatic arteries notwithstanding the sloping situation of the testicles and of the ovaries, since it manifestly depends on the spermatic cord being situated at first higher and more internally.

The trunk of the epigastric artery divides below into two branches, the external, which is generally the larger, and the internal, the smaller ; it then ascends on the posterior face and in the substance of the rectus abdominis muscle, sends off several branches outwardly, one of which is frequently larger than the others, in the internal part of the broad abdominal muscles, gives branches to these, the recti, and to the pyramidales muscles, and to the peritoneum, and terminates near the centre of the abdomen, by anastomosing with the branches of the external thoracic, the inferior intercostal, and the internal mammary arteries.

The epigastric artery is situated on the outside of the tumor in internal inguinal hernia, and on the inside in external inguinal hernia ; so that in the former case it is wounded when the incision is carried outward and in the latter case when the bistçry is directed inward. It is rarely so far distant from the inside that it is raised with the umbilical artery or with the remnant of this vessel, and consequently proceeds on the inside of the tumor, even in an internal inguinal hernia.(l) In crural hernia it is usually found outward, so that we run the risk of opening it when we cut in this direction. It is however difficult to wound it when it does not arise lower than usual, while this is easy when it comes from the crural artery, in which case it sometimes


(1.) Bekkers, he, cit, p. 316


ÀNGEIOLOGV.


323


ascends on the outside of the inguinal ring, sometimes passes before this opening to go to its inside ; it may also be divided, when, although it does not arise lower than usual, it descends first superficially and resumes its situation afterward to go toward the umbilicus.

§ 1491. Sometimes a considerable branch arises from the inside of the iliac artery, below this artery, the following, or finally the crural arch. This is half as large as the epigastric artery, and ascends outside of the inguinal ring, between the external face of the obliquus abdominis muscle and the skin, gives branches to this muscle, particularly to the integuments, extends to the umbilical region, anastomoses below with the epigastric artery, and may be considered as the second epigastric artery. When this branch exists, it is also found on the outside of the tumor in an external inguinal hernia, and it is wounded if the bistory is carried in that direction.

II. CIRTUMFLEX ILIAC ARTERV.

§ 1491. The circumflex or anterior iliac artery {Jl. abdominalis , s. civcumflexa iliaca externa , s. iliaca externa minor , s. epigastrica externa ) usually arises on the outside of the iliac artery, opposite the epigastric artery, which is generally a little larger than it. As however it is more constant in its origin than the latter, it is not unfrequently placed more or less below it. It frequently comes from above the epigastric artery, although the latter arises at its usual place. In some subjects it even arises from the crural artery, directly below the crural arch, but always at least from its outside. It goes directly outward and upward toward the iliac crest, frequently sends branches to the tensor fasciae latæ and sartorius muscles, always give them to the iliacus muscle, and following the direction of the crest of the ilium, proceeds from before backward and from within outward, in the lower and middle part of the broad abdominal muscles, between which its principal branches penetrate. The latter anastomose with the ileo-lumbar and epigastric arteries. Others, which go outward, toward the great trochanter and the sartorius muscle which they accompany, communicate with the ramifications of the crural artery.

This artery is not unfrequently divided into two trunks, one of which generally arises a little below the epigastric artery.

The external branch is generally much larger than the other, but sometimes becomes a small branch, while the principal branches of the artery go obliquely inward and upward. In this case, when one or more of these branches are considerably large, the operation of paracentesis might give rise to a formidable hemorrhage. (1)

(1) Ramsay, Account of some uncommon muscles and vessels, in the Edinb. med. and surg. jmtrn., vol. viii. p. 282, tab. 1, fig'. 1.


324


INSCRIPTIVE ANATOMY


ARTICLE THIRD

CRURAL ARTERY.

§ 1493. The external iliac artery after emerging from the crural arch, under the centre of which it passes, is called the crural or femoral artery [A. cruralis, s. femoralis communis s. cruralis inguinalis , s. cruri inguinalis). It is situated in this place on the neck of the femur, almost directly below the skin, covered only by the fascia lata aponeurosis, the fat, and the lymphatic glands of this region, over the vein which accompanies it, and occupies nearly the centre of the space between the symphysis pubis and the anterior and superior spine of the ilium, between the adductor muscles of the thigh on one side, the rectus anticus and the sartorius muscles on the other.

Beside the small inconstant ramifications which it distributes to the skin, to the muscles, and to the lymphatic glands of this region, it gives off, sometimes higher and sometimes lower from its inside, one, two, and even three external pudic , scrotal , or vtdvar arteries, the upper, the lower, and the lowest (A. pudendœ externa , superior, inferior et infima , s. tertia).

These arteries, which proceed directly under the skin, go from without inward in the integuments and the fat of the pubis and of the lower part of the abdomen, the inguinal glands, the scrotum, and the labia pudenda, where they form the anterior scrotal and labial arteries (A. scrotales et labiales anteriores). To this is referred the second epigastric artery mentioned above.

§ 1494. The crural artery has not always the same extent. Its length is principally determined by the origin of the deep femoral artery, which always arises from its posterior and inner side, so as to be covered by it. This branch is generally given off from the trunk one or two inches below the crural arch, rarely higher, (1) but sometimes also it arises directly below the arch or even, which is always very rare, above it. On these differences depend also those in the size of the superficial and deep crural arteries or of the continuation of the trunk. When the crural artery arises very high it is usually much larger than common, nearly equal to the superficial in size, and then it frequently gives off the upper branches of the latter, particularly the external pudic arteries, but more frequently still the circumflex arteries, which we shall mention directly. Sometimes the latter and the deep crural artery arise from a common trunk and at the same place.

(I) Burns has already corrected the error made by Bell, who asserted that this division usually occurred four inches above the crural arch.


ANGEIOLOGY.


325


I. DEEP CRURAL ARTERY.

§ 1495. The deep crural artery (A. cruralis , s. femoralis profunda) gives off frequently, not far from its origin, two branches, called the circumflex arteries of the thigh (A. circumjlerœ femoris ), which are distinguished into external and internal. This however is not always the case. Sometimes, but very rarely, these two arteries (more frequently one of them, particularly the internal, and very rarely the external) arise from the common crural or even from the superficial crural artery, below the origin of the deep femoral artery,

I» CIRCUMFLEX ARTERIES.

§ 1496. The internal circumflex artery {A. circumflexa femoris interna ) generally arises higher than the external. Its origin is sometimes two or three inches above that of the latter ; hence it comes more frequently than the other from the common crural artery, directly below the crural arch and the epigastric artery, higher even than the three external pudic arteries, and it is thus sometimes given off by the external iliac artery. It generally comes from the inside, but in some subjects from the outside of the common crural artery. In this case it gives one or more branches, which go outward and upward, into the inguinal glands, the iliacus and the sartorius muscles, and anastomose with those which arise from the crural artery. The trunk goes inward, passing in the second case below the crural artery, and at the same time descending a little when not unusually high. It gives branches to the lower part of the psoas and iliacus, the pectineus, to the short and long adductor muscles, afterward goes deeply inward and backward, below the pectineus muscle, and immediately around the neck of the femur, and divides behind the pectineus into two branches, a superior or anterior and an inferior or posterior.

The superior is smaller and soon subdivides into two branches ; the external and smaller is called the artery of the cotyloid cavity (A. acetabuli) ; it goes to the capsular ligament and to all parts of the articulation, turns on the head of the femur, anastomoses by a large ramus cule with the obturator artery, and distributes branches to the obturator externus muscle. The internal is larger, passes behind the adductor longus and brevis, and is expanded in the upper part of the adductor magnus muscle.

The inferior branch is much larger than the preceding, and is the continuation of the trunk. It descends backward, behind the adductor magnus muscle, is distributed principally to the gracilis muscle, the three long flexors of the leg, the long head of the biceps femoris, the semimembranosus and the semitendinosus, and finally becoming sometimes one, sometimes two branches, called the trochanterian, which are distinguished into an upper and lower (R. trochantericus superior et infe

326


DESCRIPTIVE ANATOMY.


rior), it is reflected from before backward, on the inner part of the femur, then outward and upward, to arrive at the great trochanter, ascends before the gemelli and quadratus femoris muscles, between them and the obturator externus muscle, gives branches to these muscles, and also to the tendon of the obturator internus and pyriformis, and anastomoses with the external circumflex, the gluteal, the ischiatic the inferior hemorrhoidal, and the obturator arteries. This inferior branch is sometimes smaller, and is distributed only to a portion of the adductor magnus and to the gracilis muscles ; all the other ramifications, especially the anastomotic, arising from the superior.

Beside the anastomoses between the external and the internal circumflex arteries at the posterior part of the thigh, these two arteries often unite by a very large transverse branch on the anterior face of the bone, which, added to their communication with the crural artery, completes the circle of anastomosis.

By all these anastomoses the internal circumflex artery is the principal channel through which the blood comes to the lower extremity â– when the external iliac artery is tied. It is consequently one of those vessels which are considerably dilated after this operation.(I)

§ 1497. The external circumflex artery (Jl. circumflexa femoris ex terna) arises still more frequently than the preceding, although not always from the outside of the deep crural artery. It comes sometimes from the place where this latter is given off from the common femoral artery, and sometimes much lower.

It goes obliquely outward, turning on the anterior face of the femur, directly on the upper part of the cruræus muscle, gives small branches to the lower extremity of the iliacus muscle, and soon divides into an ascending and a descending branch.

The descending branch which arises sometimes wholly, sometimes partially, from the superficial or from the deep femoral artery, gives ramuscules to almost all the outer part of the triceps extensor, also to a small portion of the rectus femoris muscle, and sends upward, across this muscle, a transverse vessel which goes to the large trochanter, penetrates into its substance, and forms a net work on its surface by anastomosing with the ramifications of the internal circumflex artery.

The ascending branch penetrates from before backward and from within outward, principally into the gluteus médius muscle, passes above the great trochanter, and anastomoses in this place with the internal circumflex, the gluteal, and the ischiatic arteries.

These anastomoses are also very much dilated when the external iliac artery is tied.

• II. PERFORATING ARTERIES.

§ 1498. The deep femoral artery after giving off the circumflex arteries goes backward, inward, and downward, so that it descends

(1) A. Cooper, Account of the anastomoses of the arteries of the groin ; Med. Chir. TVans., vol. iv. p. 424.


ANGEXOLOGY.


327


on the inside of the femur, between the vastus internus externally, the adductor longus and brevis internally, and the superficial femoral artery forward. In this course it generally gives off some anterior and several posterior branches ; the latter are larger and more constant.

The anterior generally arise very high from the outer and inner sides of the artery. Sometimes there is only one and sometimes we find several on each side. The external goes to the vastus intemus and penetrate also to the crurales muscle. The internal go to the adductor magnus and adductor brevis muscles, and, passing between these two muscles, arrive at the upper and middle part of the gracilis intemus muscle, of which they are the principal nutritious vessels.

Properly speaking, the trunk of the deep femoral artery divides to give rise to the posterior branches, since it penetrates much farther back, to the posterior part of the thigh behind the femur.

These branches have been termed the perforating arteries (A. femoris perforantes), because they pass through the adductor magnus muscle to the parts behind it.

They vary in number from one to five ; for sometimes the whole trunk, or at least that part from which the perforating arteries generally arise, goes backward, after passing through the summit of the adductor magnus muscle, and then descends behind this muscle, while in other cases it proceeds before it, and gradually gives off branches, which pass through it to arrive at the posterior part of the thigh. This diference is sometimes observed in the two lower extremities of the same subject.

The saper ior or first perforating artery commonly divides into two branches, an upper which ascends, and a lower which descends.

The superior branch ascends toward and around the great trochanter, on which it anastomoses with the ramifications of the external circumflex artery, and penetrates into the lower part of the .gluteus maximus muscle, where it communicates with the gluteal artery.

The inferior branch turns around the femur forward and outward ; it is distributed to the vastus extemus and to the rectus, and to the long head of the biceps muscles. It also gives off the nutritious artery of the femur {A. nutritia ossis femoris ).

The second and third perforating arteries sometimes arise opposite each other, one from the outside the other from the inside of the femoral artery. The external goes to the triceps extensor muscle, the internal is distributed to the biceps, the semitendinosus, and the semimembranosus muscles.

Sometimes we find also two other perforating arteries, an external and an internal, which are distributed in the same manner.

In some subjects the upper branch, then unusually large, is the only one which passes through the adductor magnus muscle. It divides into two branches, an ascending which gives all the internal ramifications to the flexor muscles ; the inferior is larger, and gives off all the external ramifications except the first. The latter is not visible


32S


DESCRIPTIVE ANATOMY.


externally, but directly where the adductor magnus muscle is inserted it passes through this muscle to empty itself from within outward, in the vastus externus and the rectus femoris muscles.

The sciatic nerve also receives considerable branches from the perforating arteries.

A large branch, the anterior extremity of the trunk of the deep femoral artery, always descends before the adductor magnus muscle, between it, the adductor longus and brevis muscles, distribute branches to these muscles, and near the centre of the thigh give off the inferior nutritious artery of this bone.

Many of these branches, especially the lower, sometimes arise from the superficial, and not from the deep femoral artery. They all anastomose with each other. Farther the superior, as we have already observed, communicate with the external femoral and the gluteal arteries. The lower and the middle are connected by large anastomosing branches with recurrent branches, which arise from the lower part of the superficial femoral and the popliteal arteries.

Thus when the common or superficial artery is obliterated to a greater or less extent, the perforating branches of the deep femoral artery, and generally all its ramifications, are very much dilated, larger even than the trunk, as is proved by the observations of Deschamps, ( 1 ) Dupuytren, (2) and Astley Cooper. (3)

The deep femoral artery supplies the blood to most of the muscles of the thigh, to almost all the skin of this extremity, and to its bone ; it also gives origin to the accessory vessels for the circulation of the blood in the lower extremity.

II. SUPERFICIAL FEMORAL ARTERY.

§ 1499. The superficial femoral artery (Jî. femoralis superficialis , s. cruralis femoralis, s. cruri-femoralis , s. femoro- tibial is), after the origin of the deep, penetrates a little farther, between the vastus internus on one side and the adductor longus and brevis on the other, passes below the sartorius, to arrive at the inner side of the thigh, proceeds before the adductor muscles to the commencement of the lower fourth of the thigh, enters in this place the tendon of the adductor magnus muscle, and thus comes on the posterior face of the limb, where it is called the popliteal artery.

In its course it gives off branches, of which the principal are the internal and the external ; but it also sends off anterior and particularly posterior branches, especially at its lower part.

The internal branches are distributed in the adductor, the gracilis and the sartorius muscles.

(1) Observ. anat. failcs sur un sujet opéré suivant le procédé de Hunter, d'un anéurysme de l’artère poplitée ; in the Mém. prés, â l’instit., 1805, vol. i. p. 251.

(2) Journ. de Corvisart, vol. vii. p. 536.

(3) Dissection of a limb , on which the operation for popliteal aneurysm had been performed, in the Med. chir. trans ., vol. ii. p. 250.


ANGEIOLOGY.


329


The external are distributed in the latter, to the rectus, and particularly to the vastus internus ; the deep pass behind the femur, and go to the vastus extemus.

The anterior distribute blood to the sartorius muscle and to the skin-, to which also go some ramifications of the other branches.

The posterior go to the vastus internus, but particularly to the lower part of all the flexors of the leg, and as they turn around the femur they also penetrate into the vastus extemus and extend to the skin. They anastomose by large branches above with the perforating arteries, below with the superior and inferior articular arteries.

The superficial femoral artery deserves its name, because, during its whole course, it is situated near the skin. It is covered for a short distance by the sartorius muscle which crosses it. We may then easily find it in operations. The place where it is exposed in Hunter’s operation for aneurism is directly below the lower edge of the sartorius muscle at the inner part of the anterior side of the thigh.(l) The objection that when we operate in this place the articular arteries are lost and the circulation cannot continue is unfounded, (2) since when the superficial femoral artery is entirely obliterated, the anastomoses of the branches of the deep femoral artery with the lower branches of the superficial, and with those of the popliteal artery, supply channels which are large even in the normal state, and through which the blood may pass from the branches of the deep femoral into the articular arteries, and into all the parts below the ligature,

III. popliteal artery.

§ 1500. The popliteal artery (A. poplitaea , s. cruri-poplitcea, s, femoro-poplitcea) is the lowest portion of the femoral artery, and descends into the calf of the leg, inclining a little from within outward ; it extends from the beginning of the lower fourth of the femur to the summit of the upper fifth of the leg. Sometimes it is much longer, because the superficial femoral artery penetrates the adductor magnus higher, and also divides a little higher.

It is separated at its upper part from the femur and from the posterior face of the capsular ligament of the femoro-tibial articulation at its central part, by an abundance of fat and cellular tissue. The tibialis posticus muscle separates it below from the tibia.

Behind, it is separated at its upper part from the skin by the sciatic nerve and the popliteal vein, by fat and by mucous tissue ; in its lower part, by the muscles of the calf of the leg, and the plantaris muscle.

Above, it is separated by abundance of fat and cellular tissue, outward from the biceps femoris muscle, and inward from the semitendi (1) Home, An account of Hunter's method of performing the operation for the cure of popliteal aneurysm, in the Trans, of anass. for the improv^oi med. and surg. knowl., vol. i. no. 4. Additional cases, &c. ibid. vol. ii. no. 19 (2) DeschampS, loc. cit ., vol. i. p. 254.

Vol, II 42


33 Ü


DESCRIPTIVE ANATOMY


nosus and the semimembranosus muscles. The two upper heads of the triceps extensor muscle closely envelop it at its lower part. It is then looser and also nearer the bone above and below, but is every where surrounded with an abundance of fat and cellular tissue. This circumstance, added to the prominence of the flexor muscles of the tibia and of the fibula, renders it difficult to fix it and to compress it.

§ 1501. Beside certain inconstant branches which, when it passes through the tendon of the adductor magnus muscle higher than usual, appear near its origin, on the posterior face of the thigh, it gives off,

1st. From its upper part or crural portion, particularly from the posterior and inner side of this portion, several branches, which go to the lower part of the flexor muscles of the tibia.

2d. Lower down three superior articular arteries {Jl. s. rami articulares superior es), which are distinguished into internal, external, and middle, which sometimes, even usually, all, or at least two, arise by a common trunk from the anterior side of the popliteal artery. Some of these arteries are double in some subjects, then only one is detached from the trunk before the other, and the superior anastomoses with the muscular branches mentioned before. The internal and external are usually larger than the middle.

§ 1502. The external superior articular artery (A. articularis genu superior externa ) rests directly on the tibia, and passes between this bone and the common tendon of the biceps muscle, usually goes from below upward, but always from behind forward and from within outward, and gives off, in its course, ramifications to the inferior belly of the biceps muscle, also to the lower part of the vastus externus, is distributed on the outer condyle of the femur, penetrates into the articular capsule, gives branches to all the ligaments of the keee, and communicates, by a very large anastomosing branch which proceeds across to the anterior face of the femoro-tibial articulation, on the common tendon of the extensors of the thigh, on one hand, both on the side and forward with the ascending branches of the external inferior articular artery on the other, on the median line and fonvard, with a similar branch of the internal superior articular artery.

§ 1503 . The internal superior articular artery {Jl. articularis genu superior interna ) varies more than the external and the middle in respect to its origin, for it not only forms a distinct trunk much more frequently than the latter, but it also not unfrequently, in fact almost normally, arises very high, as it sometimes comes from the superficial femoral artery, and then descends along the inner edge of the vastus internus muscle, to which it distributes ramifications. In this case, we find at the most normal place of its origin, a small artery, which is sometimes a branch of a common trunk of the articular arteries, and sometimes arises directly from the popliteal artery, and anastomoses with the superior internal articular artery. When the origin of the latter is placed low, it goes a little from above downward, like the external, before it proceeds inward and forward. It divides into one or several


ANGEÏOLOGY.


331


muscular branches, which go to the lower part of the vastus internus muscle ; another median artery is situated lower, and passes behind this muscle and the common tendon of the extensors of the thigh, goes into ihe inner condyle of the femur and to the inner part of the ligaments of the knee ; finally, a third, which is superficial ; this proceeds on the anterior face of the femoro-tibial articulation, directly under the skin, anastomoses below with the branches of the internal inferior articular artery, and outwardly and transversely with the transverse branch of the external superior articular artery.

Both the external and the internal superior articular arteries give off considerable and recurrent branches, which communicate with the branches of the deep and superficial femoral arteries.

§ 1504. The middle articular artery (A. articulons genu media azijgos ) very rarely forms a distinct trunk, and is generally given oft' by the external superior articular artery. It goes forward and downward, penetrates from behind forward between the two condyles of the femur, and is distributed near the centre of the knee, in the femorotibial articulation, to the crucial ligaments, to the articular fat, to the posterior and middle part of the capsular ligament, and anastomoses with the branches of the inferior and also of the other two s uperior articular arteries.

§ 1505. Some small external and internal ramifications arise from the middle and inferior part of the popliteal artery and of its crural portion ; these are not constant and go to the lower part of the flexor muscles of the tibia and fibula. This portion then gives off the arteries of the gastrocnemii muscles and the inferior articular arteries.

§ 1506. The arteries of the gastrocnemii muscles (A. gemellce) usually arise, at least in part, above the inferior articular arteries and come from the posterior side of the popliteal artery. They are generally two, an external and an intentai, one for each of the two upper heads of the triceps suræ muscle. They rarely arise opposite each other. We frequently find also several other smaller gemellæ arteries, which however do not always exist. These vessels furnish the blood to the plantaris muscle, which however sometimes receives a proper and distinct branch.

§ 1507. The inferior articular arteries {A. articular es genu inferiores externa et interna) are usually two, an external and an internal, which generally form two distinct trunks. They arise from the anterior and lateral side of the popliteal artery, rarely at the same height. Sometimes one and sometimes the other is higher. Generally they are of the same size.

§ 1508. The external sends branches to the lower and middle head of the triceps suræ muscle. These branches however sometimes arise, at least in part, from a special branch of the popliteal artery. The artery then, passing directly above the external head of the tibia, below' the external lateral ligament of the knee, and on the capsular ligament of the articulation, goes thus from behind forward In its course it


3 iS*


descriptive anatomy.


gives branches to the articular capsule, and anastomoses on one side by ascending lateral branches with the descending branches of the external superior articular artery, on the other by a large transverse branch, which passes above the lower part of the anterior face of the tendon of the extensors of the thigh, below the patella, with a similar transverse branch from the internal inferior articular artery.

§ 1509. The internal usually proceeds a little downward, goes from behind forward and from without inward, below the internal head of the triceps suræ muscle, directly surrounds the inner condyle of the tibia, gives numerous branches to the popliteus muscle, sends downward other branches, which anastomose on the internal face of the tibia with the recurrent branches of the posterior tibial artery, gives also others, which are larger and transverse, which communicate directly above the insertion of the common tendon of the extensors of the thigh with the recurrent branches of the anterior tibial artery, and finally goes upward and forward on the external anterior face of the ligament of the patella, where it anastomoses by several ramifications with the internal superior and with the external inferior articular arteries.

§1510. Besides these two inferior articular arteries, we sometimes find a middle articular artery (A. articularis inferior media, s. azygos ), which however arises oftener from the internal, and which penetrates from behind forward in the fernoro-tibial articulation, on the median line, between the two condyles of the tibia.

The popliteal artery generally gives off no other branches than those which have been described ; it is then the principal source of the anastomotic articular branches, by which, from the communication established between the upper and the posterior branches of the deep femoral artery, or between the inferior and recurrent branches of the arteries of the knee, the circulation of the blood may continue regularly in the leg, even when the superficial femoral and the popliteal arteries are obliterated. Thus these vessels are very much dilated after an operation for popliteal aneurism, where the superficial femoral and the popliteal arteries are obliterated.


ARTICLE FOURTH.

ARTERIES OF THE LEG.

§ 1511. The popliteal artery generally, after passing an inch without giving off any branches except those which go from its lower part into the soleus or to the third head of the triceps, suræ muscle, divides about an inch below the knee, very rarely higher and opposite the articulation, into two branches, called the tibial arteries (A. tibiales, s. cnemiales, Barclay). Of these two branches, the posterior is the larger, and may be considered from its direction as the continuation of the trunk, and is the common trunk of the posterior tibial and peroneal


angeiology,


333


arteries ; the anterior is smaller, separates from the trunk, and is the anterior tibial artery. The common posterior trunk is always large! than the anterior ; sometimes it exceeds it greatly in size, in which case the latter is arrested in the middle of the leg, and all the branches which it generally gives off then arise from the posterior tibial and from the peroneal artery.

It sometimes divides very high. Thus, in a case observed by Sandifort, (1) the crural artery divided directly below Poupart’s ligament. Portal(2) has also found it to divide higher than usual. Ramsay(3) has seen it bifurcate, not in fact above the knee, but at least above the popliteus muscle ; the anterior tibial artery passed before this muscle, between it and the tibia, and was there compressed by him.

I. ANTERIOR TIBIAL ARTERY.

§ 1512. The anterior tibial artery (A. tibialis antica, s. rotularis)( 4) describes a slightly acute angle to go forward above the upper edge of the interosseous membrane. On the anterior face of the leg it divides into two branches, the smaller of which is the ascending or recurrent branch ; the other is the continuation of the trunk ; the latter descends on the anterior face of the limb and is distributed on the tibial side of the leg and foot.

§ 1513. The recurrent artery {A. recurrens ' gives branches to the tibialis posticus muscle, and is situated directly on the outer face of the upper extremity of the tibia ; it proceeds from below upward, to be distributed partly in the head of the tibia, partly also to the external and lower part of the ligaments of the knee and the common tendon of the extensor muscles of the leg. It anastomoses with the inferior articular artery, and by means of it with the superior and likewise with the ramifications of the femoral artery. We must place it among the accessory vessels of the lower extremity.

§ 1514. The trunk of the anterior tibial artery descends on the anterior face of the interosseous membrane, between the peroneus brevis muscle, the extensor digitorum communis longus, and the extensor longus pollicis proprius, and is covered by the two latter. It gives outward and inward numerous short and small branches, some of which are distributed in these muscles, while others pass through them to go into the peronei muscles and even to the skin.

(1) Obs. anat. path., book iv. p. 97. The crural artery divides thereinto an anterior and posterior tibial artery, and we cannot admit that there is any doubt in regard to its high division into a superficial and a deep crural artery, since Sandifort expressly says, that on the left side the division occurred as usual in the calf of the leg.

(2) Anat. méd., vol. iv. p. 230.

(3) Account of an unusual conformation of some muscles and vessels ; in the Edinb. Med. Journ., vol. viii. p. 283.— Barclay, loc. cit., p 263.

(4) We describe this artery first, although from its direction and its small size it ie not the continuation of the trunk, because it corresponds to the radial artery in its distribution.


334


DESCRIPTIVE ANATOMY.


When the posterior tibial or the peroneal artery is unusually large the anterior tibial artery terminates on the back of the foot or in the leg! Sometimes it does not exist as a separate trunk, and is replaced in the leg by the perforating branches of the posterior tibial artery and on the back of the foot by the peroneal artery. In some subjects also it is obliterated at the articulation of the foot, while above and below this part it admits the blood and is distributed as usual.(l) It generally furnishes the dorsal arteries of the foot and those of the large toe.

Near the lower end of the leg, it gives off the two malleolar arteries (A. malleolar es), an external and an internal, w r hich vary much in their size and place of origin.

§ 15.1 5. The external malleolar artery {A. malleolaris externa ) often arises a little higher than the internal, then descends from behind forward between the tibia and the fibula, resting directly on these bones and below the tendon of the peronei muscles, goes outward, expands on and in the external malleolus, frequently sends branches also to the anterior part of the lower end of the tibia, gives ramifications to the extensor hallucis brevis and abductor minimi digiti muscles, and anastomoses by a large branch with the recurrent branches of the tarsal artery on the anterior face of the articulation of the foot, and also with the anterior branches of the peroneal artery on the outside of the os calcis. This branch is constant, but it varies in size, and when large it partially or wholly gives off the dorsal artery of the foot. Sometimes it does not arise from the anterior tibial but from the peroneal artery, when the latter is unusually large. It is rarely given off by the peroneal artery, and arises still less frequently from the posterior tibial artery.

§ 1516. The internal malleolar artery (A. malleolaris interna) usually arises a little below the preceding. It not unfrequently divides into several branches, which are given off from the anterior tibial artery, one on the tibia and the other on the tibio-tarsal articulation.

It proceeds from without inward, under the tendons of the tibialis anticus and the extensor digitorum longus muscles, resting directly on the tibia and in the second case on the capsular ligament, arrives at the internal malleolus, distributes branches to this eminence, to the capsule of the articulation of the foot, to the astragalus, and anastomoses with the branches of the tarsal and posterior tibial arteries.

When two internal malleolar arteries exist, they communicate with each other.

This artery also sometimes arises, but more rarely than the preceding, from the peroneal or the posterior tibial artery.

§ 1517. After giving off the malleolar arteries, the trunk of the anterior tibial artery passes under the tendons of the extensor digitorum communis longus, on the outside of the extensor hallucis proprius, and comes on the back of the foot, giving off right and left small branches,

(1) This arrangement does not necessarily arise from the primary formation ; it. may, as Burns correctly remarks (or Barclay, toe. cit., p. 293), t e accidental and ho produced by compression. This ougnt also to be admitted in the second case


ANGEIOLOCiY.


335


which go into the periosteum, the dorsal ligaments of the tarsus, and the tendons of the extensor and peroneus brevis muscles. In this place it is called the dorsal artery of the foot (A. pediœa). The latter is rarely the continuation of the trunk of the peroneal or of the posterior tibial artery.

§ 1518. Internal and external branches arise from the dorsal artery of the foot. The latter are more numerous, larger, and more constant than the internal. We observe two particularly, the tarsal and the metatarsal artery.

The tarsal artery (A. tarsea ) arises from the outside of the dorsal artery of the foot, sometimes higher and sometimes lower on the back of the foot, even above the lower extremity of the tibia, in which case the external malleolar artery is very small ; this vessel is considerable, and its caliber almost equals that of the continuation of the trunk of the anterior tibial artery ; thus it would be more convenient to term it the external tarsal artery {A. tarsea externa ), in opposition to another branch which corresponds to the inside.

This tarsal artery goes transversely outward on the astragalus and os calcis, gives branches to these bones and also to the external part of the ligaments of the tibio-tarsal articulation and to the tarsus, sends off toward the external malleolus a large branch which anastomoses with the external malleolar artery (§ 1515), communicates on the outside of the os calcis with the branches of the peroneal artery, gives off forward other branches which unite to those of the metatarsal artery, penetrates to the cuboid bone, to the posterior extremity of the fifth metatarsal bone, anastomoses also with the external plantar artery on the outer edge of the foot, and distributes branches to the extensor digitorum brevis and to the abductor minimi digiti muscles.

§ 1519. Next comes the metatarsal artery (A. metatar sea ), which also arises from the outside of the dorsal artery of the foot, and varies so much in regard to its origin that it is sometimes a branch of the tarsal artery, and sometimes arises several inches distant from it, and from the dorsal artery of the foot, directly behind the anterior edge of the tarsus.

It is generally smaller than the preceding. Its direction, like that, is from within outward, assuming a course more transverse as it arises farther forward, and is always situated below the extensor digitorum brevis muscle. It is more or less evidently convex forward, and forms an arch, which is completed outwardly by the anastomosis constantly existing between it and the tarsal artery. This arch, on the outer edge of the tarsus, is changed by the smaller but constant branches of the tarsal artery into a vascular net-work, which covers most of the back of the foot. When this artery arises far backward, we usually find a second, which is smaller and proceeds on the anterior edge of the dorsal face of the tarsus, and which communicate with the posterior by very analogous longitudinal branches, which correspond in number and situation to the three external interosseous spaces. This second artery is not so much a branch of the dorsal artery of the foot as the result of


336


MESCltlPTJVE ANATOM V.


anastomoses between these longitudinal branches and the dorsal interosseous arteries.

Sometimes there are even three metatarsal arteries, a third existing between the two we have mentioned.

A transverse arch, the convexity of which looks forward, constantly forms on the anterior part of the dorsal face of the tarsus or on the posterior part of the metatarsus. This arch contributes more or less but constantly with the posterior perforating arteries given off by the inferior tibial artery to form the dorsal interosseous arteries (A. interosseœ dorsales),

This vascular net-work is termed the dorsal arch of the tarsus (Æ. dorsalis tarseus). It varies much in extent and complexity.

A dorsal interosseous artery proceeds in each space between two metatarsal bones. These arteries are always very large and sometimes of an enormous caliber. They are four in number ; but the first or the most internal, comprised between the first and second metatarsal bones, is considered as the continuation of the trunk and is called very improperly the external dorsal artery of the large toe (A. hallucis dorsalis).

All these dorsal interosseous arteries are similar in the following respects :

1st. They anastomose by their posterior extremity with the posterior perforating arteries.

2d. They communicate with the anterior perforating arteries by their anterior extremity, between the bases of the first phalanges of the toes,

3d. They give off, outward and inward, branches, by which they anastomose with each other on the back of the tarsus, and which are distributed in the external interosseous muscles, the bones of the metatarsus, the abductor pollicis longus, and the skin of the dorsal face of the tarsus and of the toes. The branches which go to the toes, each of which receives at least two, the tibial and the peroneal , are called the dorsal arteries of the toes {A. digitales dorsales tibiales et peroneœ)

These superior interosseous arteries sometimes divide anteriorly into two branches, the tibial and the peroneal , each of which always goes to a different toe.

From the outer part of the tarsal arch a branch usually arises, which is also connected with the superior interosseous arteries, but which goes to the abductor minimi digiti muscle, and sometimes arises from the fourth interosseous artery, or, according to the usual way of numbering them, from the third. This last also most generally gives off another branch to the fibular side of the little toe, the dorsal peroneal branch of this appendage, while itself gives off the dorsal tibial branch.

Sometimes butrarely the second superior interosseous artery, generally called the first, does not arise from the metatarsal artery, but from the continuation of the trunk of the dorsal artery of the foot, and then the latter corresponds more than usual to the middle of the dorsal face of ♦he tarsus.


ANGEIOLOGY.


337


§ 1520. The internal branches of the dorsal artery of the foot are smaller than the external. They are generally as numerous, but usually there is only one very large. That arises about the centre of the tarsus, a little before the anterior extremity of the astragalus. It is well called the internal tarsal artery {A. tarsea interna).

This artery proceeds obliquely from without inward and from behind forward, distributes branches to the internal half of the bones of the tarsus and also to the first metatarsal bone, to part of the extensor digitorum brevis and of the abductor pollicis pedis, and anastomoses with the dorsal artery of the back of the foot on the dorsa.1 face of the tarsus, with the first interosseous artery, with the internal plantar artery on the inner edge of the foot, finally with the internal malleolar artery, and thus contributes to form the dorsal arch of the tarsus.

§ 1521. The trunk of the dorsal artery of the foot divides, between the posterior extremities of the first and second metatarsal bones, into two branches : one is the continuation of the trunk, the first metatarsal artery, usually termed the dorsal artery of the great toe {A. dorsalis hallucis) ; the second, the deep anastomosing branch (R. anastomoticus profundus ), passes directly to the sole of the foot, between the two bones, and forms with the external plantar artery the deep plantar arch {A. plantaris profundus), whence arise most of the plantar arteries of the toes (A. digitales plantares).

The dorsal artery of the large toe usually proceeds from behind forward on the back of the foot, along the external edge of the toe, and there divides into two branches, which become, one the common dorsal artery of the large toe , the other the dorsal tibial branch of the second toe.

It anastomoses most generally either at its place of origin or by one of its two branches with the plantar artery of the large toe.

II. POSTERIOR TIBIO-PERONEAL ARTERY.

§ 1522. The common trunk of the posterior tibial and peroneal artery, called also the tibio-peroneal artery, or simply the posterior tibial artery (A. tibio-peronea, s. tibialis postica, s. tibialis poplitea), descends vertically behind the interosseous membrane, covered by the heads of the peronei muscles, and generally, soon after the origin of the anterior tibial artery, g'ives off two considerable branches, an external and an internal.

The internal branch sends off small twigs to the popliteus muscle, penetrates principally into the tibia as the upper nutritious artery {A. nutritia tibiae superior ), and gives off from behind forward, into the periosteum of this bone, ramifications which anastomose on its internal face with those of the inferior and internal articular artery (§ 1509).

The external branch gives off ramuscules to the lower or middle head of the triceps surse muscle, proceeds below it, around the upper extremity of the fibula, sends off ramifications to the upper part of the

Vol II 43


338


DESCRIPTIVE ANATOMY.


peroneus longus muscle, and anastomoses both with the anterior tibial (§ 1511) and with the descending branches of the external inferior articular artery. These two branches consequently contribute to enlarge the system of the accessory vessels of the leg.

§ 1523. After giving them off, the tibio-peroneal trunk, which sends only inconstant branches to the soleus muscle, divides generally from one to two inches below the origin of the anterior tibial artery into two branches, the peroneal artery and the posterior tibial artery.

I. rERONEAL ARTERY.

§ 1524. The peroneal artery ( A . peronÅ“a , s. fibularis) generally but not always arises at the place mentioned. Sometimes, but much more rarely, and only when the popliteal artery divides unusually high, it arises above, more frequently below, this point, and in the second case it is smaller in proportion as its origin is lower. Sometimes, in fact often, it does not exist, and it is replaced by the branches which are successively given off from the posterior tibial artery. Independently of its point of origin it varies very much in respect to its volume, a circumstance in regard to which it increases and diminishes inversely with the anterior tibial artery. It is generally smaller than the two tibial arteries ; but sometimes when one of the latter is deficient it is much larger than usual.

It descends on the posterior face of the interosseous ligament, covered by the soleus muscle, on the inside of the flexor longus digitorum communis muscle, gives its largest branches to these two muscles and also to the peronei, usually sends off, near the lower extremity of the leg, rather a large branch, which, passing under the posterior tibial artery, is called the posterior internal malleolar artery (A. malleolaris interna posterior ) and goes to the internal malleolus, on the surface of which it frequently communicates with the anterior internal malleolar artery furnished by the anterior tibial artery (§ 1516), and terminates on the outer face and the tuberosity of the os calcis by ramuscules, which enter partly into this bone, and partly by large branches by which it anastomoses with the posterior tibial artery, thus forming the inferior plantar arch.

§ 1525. At various heights of the leg, but generally toward its lower extremity, it gives off a branch which also varies much in size and which goes to the anterior face of the limb, passing between the two bones. When this branch is considerable it is termed the anterior peroneal artery ( A . peronœa anterior). It proceeds, near the surface, on the outer and anterior face of the leg, frequently descends to the external face of the tarsus, unites to the external malleolar artery, given off by the anterior tibial (§ 1515), concurs to form the dorsal arch of the tarsus, anastomoses with the branches of the external plantar artery, and distributes twigs to the tendons of the extensor digitorum communis, to the posterior part of the extensor minimi digiti


ANGEIOLOGY,


339


muscle, to the external malleolus, to the astragalus, and to the cuboid bone.

This branch does not always arise from the peroneal artery ; it is then generally very small, and does not descend to the lower extremity of the leg or is entirely deficient. It is normally replaced by a branch of the anterior tibial given off by the external malleolar artery (§ 1515) less frequently, although more commonly than when it arises from the peroneal artery, it comes from the posterior tibial artery, and then it passes, attheusual place, on the anterior face of the leg.

The anterior peroneal artery much more rarely not only arises higher than usual, sometimes even not far from the middle of the anterior face of the leg, so that it sends off in this place ramifications to the peronei and to the extensor digitorum communis muscle, but it is also so large that it gives off the external malleolar artery ; and the dorsal artery of the foot is even the continuation of its trunk, and then the anterior tibial artery is very small, terminates on the back of the tarsus, and anastomoses with it.

Not more frequently the peroneal artery, extends farther than usual in the sole of the foot, and gives off the external and the internal plantar arteries. We have before us only one specimen of this anomaly. At the same time the anterior tibial artery is extremely small ; it stops at the middle of the leg, and all the branches it generally gives off below this point arise from the posterior tibial artery, which passes to the anterior face of the limb, about the level of its lower fourth.

II. POSTERIOR TIBIAL ARTERY.

§ 1526, The •posterior tibial artery (A. tibialis postica) is generally much larger than the peroneal artery, but its direction varies more than that of the primitive trunk, and it proceeds slightly inward.. It is generally a little larger than the anterior tibial artery and sometimes very much exceeds it in size. It descends, covered above by the third head of the triceps suræ muscle, between this muscle, the flexor longus digitorum communis and the tibialis posticus, and is entirely loose at its lower part, being covered only by the crural aponeurosis and the skin and the posterior face of the tibia, on the inside of the tendo-Achillis. In its course it gives off posteriorly numerous small branches to the soleus muscle and the tendo-Achillis, and anteriorly to the tibialis posticus on flexor longus digitorum communis muscles. At the lower part of the leg it sends off several larger branches both outward and inward ; these anastomose frequently, on the two malleoli, with the internal and external malleolar arteries, given off by the anterior tibial artery.

Theposterior tibial artery, proceedingbetween the tendons of the flexor longus digitorum communis and the tibialis posticus muscles, situated on its inside, and that of the extensor pollicis pedis on the outside, so that it passes on the latter, leaves the posterior face of the leg, and arrives at the sole of the foot, where it is situated on the posterior face of the os calcis.


340


DESCRIPTIVE ANATOMY


'Very rarely it passes from the posterior to the anterior face of the leg. thus becoming the dorsal artery of the foot. It most generally sends off, at the place where it enters the sole of the foot, a considerable branch, which goes into the os calcis and also into the lower extremity of the tendo-Achillis ; this branch anastomoses on the tubercle of the os calcis, before this tendon, with the final branches of the peroneal artery, and by means of them with the external malleolar artery ; thus a vascular plexus is formed which may be termed the inferior or plantar tarsal arch ( rete , s. arcus tarsus plantaris).

Not unfrequently another external and large branch goes to the posterior part of the abductor pollicis pedis muscle.

The posterior tibial artery then divides below the internal malleolus, about the centre of the inner face of the calcanéum, but a little behind it, into two branches, the external and internal plantar arteries.

These two branches, and the two branches described previously, very rarely arise from the peroneal artery, which happens when the posterior tibial arterv replaces the lower portion of the anterior tibial artery (§ 1525).

III. PLANTAR ARTERIES.

I. INTERNAL PLANTAR ARTERY.

§ 1 527. The internal plantar artery (A. plantaris interna ) is always smaller than the external, and vanes in size less than the latter. It follows the direction of the trunk and goes forward, under the tendons of the flexor digitorum longus muscle, above the long head of the abductor pollicis, not far from the inner edge of the foot. In its course it sends superficial branches to the abductors and the flexor pollicis brevis, and to the flexor communis digitorum brevis, gives deep branches to the inner half of the plantar face of the ligamentous envelop of the tarsus, to the os calcis, to the astragalus, and to the scaphoid bone ; anastomoses, in several places above the inner edge of the foot, with the branches of the internal artery of the tarsus and of the dorsal artery of the foot, and gives off anteriorly, between the first and second toes, generally one, often also two, branches, which form the plantar artery of the large toe, and frequently anastomoses, by an external branch, with the deep plantar arch.

II. EXTERNAL PLANTAR ARTERY.

§ 1528. The external plantar artery (A. plantaris externa) is deeper than the internal. It varies in size more than this latter. It is often scarcely visible, and again is sometimes three times the size of the internal. These differences depend principally on those in the size of the dorsal artery of the foot (§ 1517), for there is always an inverse relation between the caliber of these two vessels.

The external plantar artery immediately goes far outward. It proceeds between the abductor pollicis pedis and the flexor digitorum


ANGEIOLOGY.


341


brevis below, and the accessory muscle above, toward the outer edge of the sole of the foot, where it extends forward, on the inner edge of the abductor minimi digiti muscle, gives branches to all the muscles mentioned, and anastomoses, by several branches which reascend above the outer edge of the foot, with the arteries of the tarsus and metatarsus.

At the posterior extremity of the fifth metatarsal bone it goes inward, and gives off, either in this place or a little before, a considerable branch, the peroneal plantar artery of the fifth toe (À. digitalis plantaris peronea digiti quinti ), which goes forward on the flexor minimi digiti muscle, along the fibular edge of the toes to the anterior extremity, sends branches to its flexor muscle, to the third internal interosseous muscle and to the skin, and finally anastomoses, on the ungueal phalanx of the little toe, with the tibial branch.

The deep or internal plantar artery then goes almost transversely forward and inward, between the internal interossei and the other muscles of the sole of the foot, and anastomosing with the deep anastomotic branch of the dorsal artery of the foot, between the first and second metatarsal bones, forms the deep plantar arch , which is concave backward and convex forward, and is situated very deeply on the posterior extremities of the metatarsal bones.

III. PLANTAR ARCH.

§ 1529. The digital arteries and the anterior and posterior perforating arteries arise from the deep palmar arch.

a. Digital arteries.

§ 1530. The digital arteries (Jl. digitales) arise forward, from the convex part of the arch.

Their general characters are,

a. They are situated deeply in the sole of the foot, and proceed from behind forward, on the square belly of the flexor digitorum longus communis, and the transverse belly of the adductor hallucis.

b. Between the posterior extremities of the toes they divide into two branches, which go one to the tibial side of the outer, the other to the peroneal side of the inner toe.

c. The two branches unite on the ungueal phalanx, and also anastomose with each other and with the dorsal branches.

d. They anastomose forward with the superior and inferior metatarsal arteries at their bifurcation.

But they differ very much in regard to their origin. The deep arch most generally gives rise to the deep plantar arteries of the three outer and the peroneal branch of the second toe, less frequently to the tibial branch of this and the plantar branch of the large toe.

The peroneal branch of the little toe often comes directly from the plantar arch, and even farther behind it, from the external plantar


342


DESCRIPTIVE ANATOMY.


artery (§ 1528), but it not unfrequently arises, by a common trunk, with the tibial branch of the fifth toe and the peroneal branch of the fourth. We have never observed that when this first digital artery gave off also the tibial branch, it was destined solely for the fifth toe, and did not proceed at the same time to the peroneal side of the fourth. Even when the peroneal branch of the fifth toe forms a distinct and separate trunk, it generally communicates by large anastomosing branches, both on the metatarsus and on the first phalanx of the toe, with the second digital artery, and the tibial branch of the fifth toe.

The second digilcd artery when it does not form a trunk with the preceding, goes to the tibial side of the fifth toe and to the peroneal side of the fourth.

Next comes the third, which goes to the tibial side of the fourth toe and to the fibular side of the third. Sometimes this artery is double as far as the arch from whence it arises to the anterior part of the metatarsus ; but its two trunks there unite in one, which soon divides into two branches, the tibial branch of the fourth and the peroneal branch of the third toe. This arrangement occurs particularly when the usual number of digital arteries is diminished in any manner whatever, as, for instance, by the union in one trunk of the peroneal branch of the fifth toe and of the two following branches.

Next comes usually a fourth, which divides in the same manner for the second and third toes.

The fifth constantly forms the tibial branch of the second toe. Sometimes, when the anterior tibial artery is much smaller and the posterior on the contrary is larger than usual, it forms the common plantar artery of the large toe , from whence the tibial branch of the second also arises.

The plantar artery of the large toe and the tibial branch of the second vary the most in their origin and arrangement.

This artery is generally the continuation and termination of the trunk of the dorsal artery of the foot, which comes to the first phalanx of the large toe, goes to its plantar face, and gives origin to all the plantar and dorsal branches of this toe, sending off first the peroneal dorsal branch, then the peroneal plantar branch, next the tibial plantar branch, and finally the tibial dorsal branch, which anastomose as usual.

More rarely the continuation of the trunk of the dorsal artery of the foot divides, soon after giving off the deep anastomosing branch to the sole of the foot, into two branches, a superior, which becomes the common trunk of the dorsal artery of the large toe and the tibial branch of the second ; an inferior, or the common trunk of the two plantar arteries of this toe, which bifurcates near the centre of the plantar face of the large toe, to give rise to two plantar branches. But we must remark that here we find a similarity between the anomaly and the normal or more common arrangement first described, since the two


ANGE10L0G Y.


343


branches communicate at the base of the first two toes by a large anastomosing branch.

The superficial internal plantar artery given off by the posterior tibial artery always contributes to form the two plantar branches of the large toe and the inner branch of the second; since it constantly anastomoses near the anterior extremity of the first metatarsal bone with the trunk of these branches, and thus forms the superficial plantar arch {arcus plantaris superficialis).

When the anterior tibial artery is smaller than usual, it sometimes but not always gives off only the dorsal artery of the large toe ; sometimes too it sends off in part the tibial artery of the second. On the contrary, the trunk from which the plantar branches of the large toe and the plantar branch of the second arise, the internal plantar artery, is unusually large, and is always increased by a branch, which varies in size ; this arises from the deep plantar arch, and communicates with it toward the extremity of the first metatarsal bone.

Finally, sometimes but rarely all the arteries of the first and second toe arise only from the posterior tibial artery, particularly from the deep arch. The anterior tibial artery, which is very small, then terminates simply by a deep anastomosing branch in the deep plantar arch, and a large branch arises from the latter, which soon divides into two : one is deeper and larger, and is the continuation of the trunk ; it goes from behind forward on the first metatarsal bone, and is also enlarged by one or two branches arising from the internal plantar artery, which is also in this case unusually large, and bifurcates to give rise to the common plantar artery of the large toe and also to the tibial artery of the second ; the other is smaller and more superficial, ascends to the back of the foot between the first two metatarsal bones, gives off the dorsal branches of the large toe, and becomes, with a second digital artery given off by the deep branch, the common trunk of the tibial branch of the third toe and of the peroneal branch of the second.

6. Anterior perforating arteries.

§ 1531. The anterior perforating arteries {A. perforantes anteriores ) arise on the anterior part of the deep plantar arch, sometimes between the digital arteries. They are small and go only to the interosseous muscles, to the transverse head of the adductor hallucis muscle, and the metatarsal bones. A part of its ramifications communicate anteriorly with the digital arteries and the dorsal artery of the foot.

c. Posterior perforating arteries.

§ 1532. The posterior perforating arteries {A. perforantes posteriores) arise from the posterior and upper surface of the deep plantar arch. They give branches to the posterior part of the interosseous muscles, and also recurrent branches to the anterior part of the tarsal


344


DESCRIPTIVE ANATOMY.


ligaments and bones, and passing through the posterior extremities of the interosseous spaces, come on the back of the foot, where they anastomose with the upper interosseous arteries.

These arteries are generally small, and can be considered only as the anastomoses between the dorsal and plantar arches. However, as these latter and the dorsal interosseous arteries are generally much larger than their corresponding parts in the hand, the posterior perforating arteries are sometimes unusually developed ; so that the transverse tarsal artery sends only small anastomosing branches to their posterior extremities, in the place where they appear on the back of the foot. But in this case they are not the only origin of the dorsal interosseous arteries, which arise also from the plantar arteries of the toes and are much larger than the common trunks of the digital arteries, and which give all the digital branches commonly arising from the anterior side of the deep arch.

In this case the usual anterior branches of the plantar arch still exist, but they are merely branches for the deep muscles of the sole of the foot and the anterior perforating arteries ; so that they are as slightly developed as the dorsal interosseous arteries generally are.

There are many degrees between this state of the dorsal interosseous arteries and the common one ; so that for instance many or all the dorsal interosseous arteries contribute equally to form the digital arteries, and thus the dorsal and plantar arteries have about the same size, although it does not necessarily follow that the dorsal interosseous arteries arise from the deep plantar arch, as in the anomaly described. On the contrary, they sometimes become unusually large, but are however only the branches of the dorsal arch.

SECTION III.

OP THE VEINS OF THE BODY.

§ 1533. The veins of the body generally unite in three large trunks, which open into the right auricle (§ 1305), the large coronary vein of the heart and the two venœ cavœ.


CHAPTER 1

OF THE VEINS OF THE HEART.


I. LARGE CORONARY VEIN.

§ 1534. The large coronary vein of the heart ( vena coronaria maxima cordis) opens into the right auricle, on the left and lower side of the interauricular septum, a little way from the venous orifice of the right


A.NGEIOLOG*.


345


ventricle. It rarely empties itself into the left subclavian vein, (1) in which case the veins of the body do not unite except in two large trunks.

It arises from all the extent of the left ventricle by four or five considerable branches, which proceed downward from the summit to the base of the heart, and among which we observe three which are larger and longer than the rest.

The upper branch follows the upper groove of the convex face of the heart, which marks the upper edge of the septum. The second proceeds along its blunt edge, and the third near the inferior groove.

The smallest branches, which do not descend as low as the preceding, are situated between them.

All correspond to ramifications of the arteries, and empty at right angles into the trunk of the coronary vein, which proceeds in the transverse groove between the left ventricle and left auricle, first downward, then from behind forward to the place where it opens into the right auricle.

II. SMALL CORONARY VEIN OP THE HEART.

§ 1535. The small coronary vein of the heart (F. coronaria cordis minor , s. Galeni) belongs principally to the right auricle. It arises from the summit of the heart, proceeds in the lower longitudinal groove, or a little to the right, along the posterior and inferior edge of the right ventricle, receives the branches which come on the lower face of this ventricle, and almost always empties into the preceding, directly behind its opening. It rarely opens into the 'auricle, a little before the large coronary vein,

III. SMALL ANTERIOR VEINS OF THE HEART.

§ 1536. Besides these two large veins, others also, which are smaller and may be termed the small anterior veins of the heart , arise from the anterior ventricle, from the aorta and the pulmonary artery, and open separately into the anterior part of the right auricle. They extend from the summit to the base of the heart, proceeding before and above the preceding.

IV. SMALLEST VEINS OF THE HEART.

§ 1537. The smallest veins of the heart (V. minima cordis) conv ey the blood in every direction, even in the left half of the heart, but especially into the right auricle, through the foramina of Thebesius ( foramina Thebesii).


(1) Le Cab, in the Mém. de Vac. des sc., 1738, Hist., d. 62. Von. II. 44


346


DESCRIPTIVE ANATOMY


CHAPTER II.

VEINS OP THE I-IEAD AND UPPER EXTREMITIES.

§ 1538. The veins of the head and of the upper extremities all unite in the descending vena-cava.


ARTICLE FIRST.

VEINS OF THE HEAD.

§ 1539. The veins of the head are distinguished into the superficial or external and the deep or interned. The latter convey the blood from the brain ; the former return it from the other parts of the head. They terminate in two large trunks, the internal and the external jugular vein.

I. SUPERFICIAL VEINS OF THE HEAD.

§ 1540. Almost all the superficial or external veins of the head open into the external jugular vein. A very few of them accompany the arteries ; the largest of them however differ a little in their distribution from that of the large arterial branches to which they correspond.

Those which resume the blood from the tongue, the pharynx, the skin, and the superficial muscles of the face, finally, from the sides and from the posterior part of the skull, unite in two large trunks, an anterior and a posterior, which correspond, the former to the facial artery (§ 1351), the latter to that part of the external carotid artery which is above the facial artery, and to its outer termination, or to the temporal artery (§ 1358). These two trunks unite to form one, which is short and corresponds to most of the external carotid artery, and is called the common trunk of the superficial veins of the head ( truncus communis venarum capitis superficialium), or rather the anterior cephalic vein ( V. cephalica anterior).

A. FACIAL VEIN, OR ANTERIOR BRANCH OF TIIE ANTERIOR VEIN OF / THE HEAD.

§ 1541. The anterior trunk of the veins of the head, the facial vein , the anterior and internal facial vein ( R. vena, cephalica anterioris anticus , s. V. facialis anterior , Walter) is formed by the veins of the anterior and much the larger part of the face.

It follows the direction of the facial artery, but is situated more behind than this vessel, and as it is less tortuous, it is also some distance from it.


angeiology.


34 ?


Regarded from above downward, according to the course of the blood, this vein arises gradually by the union of the following branches : The upper branches are two in number, an anterior and internal and a posterior and external. The first is called the supra-orbitar and the second the frontal vein.


I. SUPRA-ORBITAR VEIN.

§ 1542. The supra-orbitar vein ( V. supra-orbitalis ) is situated below the frontalis muscle, proceeds transversely along the upper edge of the orbit, anastomoses externally with the frontal branch of the temporal vein, and arises from several venous twigs, which come from the orbicularis palpebrarum, the corrugator supercilii, and the frontalis muscles.


II. FRONTAL VSIN.

§ 1543. The frontal vein ( V. frontalis) arises,

1st. From the branches which anastomose with the final anterior branches of the temporal vein and also with the synonymous branches of the opposite side, form thus a very complex vascular net-work on the frontal region, and come from the frontalis muscle, from the skin, and the frontal bone. The trunk formed by the union of these branches which often unites, at the lower part of the squamous portion of the frontal bone, with the synonymous trunk of the opposite side, by a large anastomosis, and frequently forms a median branch.

2d. From an inferior branch, the superior dorsal vein of the nose ( V. dorsi nasi superior), which, after anastomosing very frequently with the inferior dorsal artery of the nose, ascends and unites with the superior branch, which we shall describe.

III. INFERIOR NASAL VEINS.

§ 1544. The supraorbital and frontal veins unite in a common trunk in the inner angle of the eye, which descends along the nose directly below the skin.

This trunk receives from before backward and from below upward, below the inner angle of the eye, first, the inferior dorsal vein of the nose ( V. dorsi nasi inferior ), then the upper anterior vein of the nose (V. nasalis anterior superior), afterward the lower anterior vein of the nose (V. nasalis anterior inferior ), which frequently anastomose together, and with the upper dorsal vein of the nose.

IV. CORONARY VEIN OF THE UPPER LIP.

§ 154G. The trunk of the facial vein next receives, as high as the ala of the nose, the coronary vein of the upper lip, which often forms a common trunk with the anterior and inferior nasal artery, and which frequently anastomoses with it.


34

DESCRIPTIVE ANATOMY


V. LOWER INTERNAL PALPEBRAL VEIN.

§ 1546. The facial vein receives at its upper part, -opposite the anterior and inferior nasal artery, the internal and inferior palpebral vein (V. palpebralis inferior interna). This vein is situated in the lower eyelid, between the skin and the orbicularis muscle ; it forms a very complex network which anastomoses externally with the upper palpebral vein, given off by the temporal vein (§ 1551), and with the external palpebral vein.

VI. LOWER INTERNAL PALPEARAL VEIN.

§ 1547. The external inferior palpebral vein ( V palpebralis externa inferior ) descends directly under the skin, along the external edge of the orbicularis muscle, anastomoses within with the upper external palpebral vein furnished by the temporal vein, outward with the internal inferior palpebral vein, and, passing under the zygomaticus major muscle, before the malar bone,- empties into the trunk of the facial vein much deeper than the preceding.

VII. UPPER AND ANTERIOR INTERNAL MAXILLARV VEIN.

§ 1548. Some distance below this external inferior palpebral vein the facial receives the upper and anterior internal maxillary vein ( V. maxillaris interna anterior superior ), which arises from the upper teeth and from the upper maxillary bone, from the posterior part of the nasal fossæ, and from the lower and anterior part of the orbit, by the following branches :

1st. The upper alveolar vein ( V. alveolaris superior).

2d. The posterior nasal vein (V. nasa/is posterior).

3d. The anterior ophthalmic vein ( V. ophthalmic a superior).

§ 1549 From this point to the lower maxillary bone the facial vein receives principally,

1st. The lower or external vein of the upper lip ( V . labii superioris inferior , s. externa), which is much smaller than the internal.

2d. The tipper buccal vein ( V. buccalis superior).

3d. The middle labial vein (V. labialis media), which is transverse, and empties itself into the trunk opposite the angle of the lips.

4th. The inferior labial vein ( V. labialis inferior).

5th. The submental vein ( V . suhmentalis).

§ 1550. It receives upward and outward, in its course,

1st. The inferior buccal vein (V. buccalis inferior).

2d. Three or four masseteric veins ( V. massetericœ), a superior, a middle, and an inferior, which arise from the substance of the masseter muscle, and form an extensive network on the surface of this muscle, which anastomoses with all the branches of the facial vein.


ANGEIOLOGt.


349


3d. The vein nf the submaxillary gland (V. glandules maxillaris inferioris).

B. COMMON TEMPORAL VEIN OR THE POSTERIOR BRANCH OF THE ANTERIOR VEIN OF THE HEAD.

§ 1551. The common temporal vein, the posterior branch of the anterior vein of the head ( V. temporalis , s. R primarius, venae cephalicæ anticÅ“ posticus, s. V. facialis posterior externa , Walter), is formed partly of superficial and partly of deep branches. The former arise principally from the middle and lateral parts of the external face of the skull ; the latter come from the deep regions of the face.

The following are the principal branches which unite below and backward to form the temporal vein :

I. EXTERNAL UPPER PALPEBRAL VEINS.

§ 1552. One or two external upper palpebral veins (V. palbebralis superior externa ) receive the blood from the tunica conjunctiva, the orbicularis palpebrarum, the skin of the upper eyelid, and frequently anastomose together, and also with the upper and lower external palpebral arteries, and the following.

II. EXTERNAL SUPRAORBITAL VEIN.

§ 1553. The external supraorbital vein ( V. supraorbitaria externa ) proceeds transversely over the upper edge of the orbit, under the orbicularis palpebrarum and the ligaments of the eyelids, and anastomoses with the external upper palpebratyveins (§ 1552).

III. EXTERNAL FRONTAL VEIN.

§ 1554. The external frontal vein (V. frontalis externa) anses front the skin of the forehead, from the frontalis muscle, from the periosteum of the frontal bone, and from this bone, anastomoses with the internal frontal vein (§ 1543) before, outward with the temporal vein, and communicates with the two or three preceding, at the outer extremity of the upper edge of the orbit.

IV. DEEP TEMPORAL VEINS.

§ 1555. These three branches are situated directly under the skin. The trunk which is formed by them, or the deep temporal vein ( V temporalis profunda ), penetrates the aponeurotic envelop of the temporalis muscle, proceeds upward and backward under this aponeurosis, above the zygomatic arch, turns very frequently, receives in its course several branches which resume the blood from the temporalis muscle and the temporal bone, anastomoses frequently with those of the facial


350


DESCRIPTIVE ANATOMY.


vein, and communicates, before the external ear and above the tern poro-maxillary articulation, with the superficial temporal vein.

V. SUPERFICIAL TEMPORAL VEIN.

§ 1556. The superficial temporal vein ( V. temporalis superficialis) is generally smaller than the preceding, and is formed by an anterior and a posterior branch, which are both situated directly under the skin. The first arises from the sinciput, the second from the upper part of the occipital region, from the upper part of the ear. They most frequently join at a right angle, and form a small common trunk, which is soon united with the deep temporal vein. These two branches frequently anastomose with each other. The anterior also communicates with the branches of the external frontal vein, and the posterior with the occipital vein.

VI. TRUNK OF THE TEMPORAL VEIN.'

§ 1557. The common trunk formed by the union of the deep and superficial temporal veins, descends on the outer face of the malar bone, comes behind the ascending branch of the inferior maxillary bone, penetrates into the parotid gland, goes forward under the angle of the lower jaw, and anastomoses in this place with the facial vein or anterior branches of the veins of the head, and thus produces a short common trunk.

In this course it receives anterior, posterior, and internal branches

VII. ANTERIOR BRANCHES.

a. Anterior articular vein.

§ 1558. The first anterior branch, counting from above downward, is the anterior articular vein ( V. articularis anterior ), which anastomoses very much with the deep temporal vein, and resumes the blood from the parts of the temporo-maxillary articulation.

b. Transverse facial vein.

§ 1559. The transverse facial vein ( V. facialis transversa) empties into the trunk of the temporal vein, a little below the preceding : it is a considerable vessel, and generally arises by a superior and an inferior branch.

The superior branch arises from around the temporo-maxillary articulation, and anastomoses with the anterior articular vein (§ 1558), and with the external infraorbital vein.

The inferior branch arises from the superficial and the deep branches.

The superficial branches carry the blood from the parotid gland, from the outer face of the masseter muscle, from the skin of this region, and from the parotid canal, and anastomose with the maxillary veins.


ANGEIOLOGÏ.


351


The deep veins come from the pterygoideus externus muscle, and then go between the neck of the jaw and the posterior edge of the masseter muscle, where they communicate with the superficial branches,

c. Parotid veins.

§ 1560. The temporal trunk receives, much lower down and anteriorly, some small parotid veins ( V. parotideœ).


VIII. POSTERIOR ERANCHES.

a. Anterior articular veins.

§ 1561. The posterior branches of the trunk of the temporal trunk, are, besides the following, the anterior auricular veins ( V. auriculares anteriores ), which arise from most of the concha of the ear.

b. Internal and posterior maxillary vein.

§ 1562. The deep branch (R. venez facialis poslerioris profundus , Walter) corresponds mostly to the internal maxillary artery, furnished by the external carotid artery. We may then term it the internal posterior maxillary vein, to distinguish it from the anterior and superior maxillary vein (§ 1548). It is formed by one or two inferior maxillary veins, and by four or five deep temporal veins, proceeds inward, before the common temporal trunk, backward and downw ard, and empties itself at some distance from the angle of the jaw, into the posterior part of the common temporal vein, after giving off a considerable branch, which descends and anastomoses with the external jugular and the occipital veins.

IX. LARYNGEAL VEIN.

§ 1563. The common trunk ot the anterior and posterior veins of the face corresponds to the external carotid artery, and usually receives anteriorly a small branch, the laryngeal vein ( V. laryngea) which arises from the mucous membrane, and from the muscles of the larynx and of the hyoid bone.

II. POSTERIOR CEPHALIC VEIN.

§ 1564. The posterior cephalic vein is formed principally by the veins of the brain, the tongue, and the pharynx.

I. VEINS OF THE BRAIN.

§ 1565. The veins of the brain may be divided into the external and the internal. The large branches produced by their union are all in

352


DESCRIPTIVE ANATOMY.


serted in the pia mater of the brain, and carry the blood into trunks called sinuses (sinus) which are formed by the inner membrane of the veins and by the dura mater. These trunks are partly surrounded by the bones of the skull, have principally transverse and longitudinal directions, communicate by several smaller sinuses, which have no constant direction, carry the blood backward and downward, and finally open into the posterior cephalic vein.

It seems to us more proper to describe the sinuses before we mention the veins of the head.

a. Superior longitudinal sinus.

§ 1566 . The superior longitudinal sinus ( sinus longitudinalis s. falciformis superior) is the longest sinus of the brain, and is situated on the median line. It occupies the convex edge of the falx of the cerebrum, directly under the frontal suture, the sagittal suture, and the upper half of the squamous portion of the occipital bone, from the crestu galli process of the ethmoid bone to the internal occipital protuberance. It has the form of a triangle, the base of which is turned upward, the apex downward ; it gradually enlarges from before backward very much, and terminates in the internal occipital protuberance, where it generally anastomoses with the right transverse sinus, in an irregular depression called the torcular herophili. We usually remark within a greater or less number of transverse cords (trabeculae) : these extend from one side to the other, and are formed internally by the dura mater, externally by the internal membrane which is reflected upon the latter.

The longitudinal sinus receives on each side, in its inferior and lateral parts, ten or twelve veins, which arise from the upper and external face and from the internal face of the brain, and which proceed in the pia mater and principally above the grooves between the circumvolutions.

The veins of the outer and upper face are the largest and the most numerous. Before they empty into the upper longitudinal sinus, they receive those which ascend along its internal face. They always proceed from before backward, increasing considerably in volume.

Most of them, with the exception sometimes of the anterior, arrive at the longitudinal sinus at very acute angles and in a direction opposite to that of the blood which passes through it.

The posterior vein, also, before opening into the sinus, usually proceeds some distance, frequently an inch between the fibres of the dura mater, which separate to receive them, and in the intervals of which they frequently curve very much.

The curves of these posterior veins are also generally supplied with single more or less apparent valves, which the anterior do not possess, because as they open into the sinus more transversely, there is less danger of the regurgitation of the blood.

The superior longitudinal sinus also receives, above, a considerable number of little veins, some of which come from the bones, while others


ANGEIOLOGY.


353


pass through the skull, and establish the communication between the internal venous system of the head, and the external branches of the temporal and facial veins. This results from the numerous ramuscules, and especially those of one or two larger veins, which passing through the parietal foramina (F. parietalia ) carry the blood from within outward.

Finally, the dura mater also gives venous branches, wririch empty into the upper and lateral parts of the superior longitudinal sinus.

6. Inferior longitudinal sinus.

§ 1567. The inferior longitudinal sinus ( S. longitudinalis, s.falciformis inferior , s. v.falcis inferior )( 1 ) is much smaller than the superior. It extends from the beginning of the middle third of the falx of the cerebrum to its posterior extremity, where it anastomoses, generally dividing into two trunks, the inferior of which proceeds along the lower and unattached edge of the cerebral falx, and empties itself into the anterior extremity of the fourth sinus, while the superior reascends between the layers of the falx and penetrates downward into the centre of the same smus.

This smus receives the veins of the falx, and in some rare cases some inferior veins of the internal face of the brain and of the corpus callosum.

c. Right sinus.

§ 1568. The fourth, right , or more properly the oblique sinus, the sinus of the tentorium (S. rectus, s. perpendicularis, s. quartus, s. obliquas, s. tentorii\ properly speaking, is only the posterior part of the preceding, but it is much larger than it. It descends obliquely from before backward, on the middle of the tentorium of the cerebellum, and occupies all the space between it and the union of the superior longitudinal sinus (§ 1566) with the transverse sinuses (§ 1571).

It gradually becomes broader from before backward and is triangular.

The transverse and oblique cords are more numerous in the anterior part than they are in the superior longitudinal sinus.

Forward and upward it receives the inferior longitudinal sinus (§ 1567). The two large internal cerebral veins, or those of Galen ( V. magnæ Galeni ), also open into its anterior extremity, below the anterior and inferior root of the inferior longitudinal sinus.

d. Large internal sinus.

§ 1569. The large internal sinus takes up the blood from the inn er parts of the encephalon, and is formed principally on each side by the


VOL. II.


(1) Bichat, Anal, desc., vol. iv. p. 394. 45


354


DESCRIPTIVE ANATOMY.


union of two vessels, the choroid vein and the vein of the corpus striatum.

The first proceeds in the choroid plexus, along the pes hippocampi, goes forward with the choroid plexus between the corpus striatum and the posterior large cerebral ganglion, and receives in the latter part of its course numerous ramuscules of veins, which go from below upward, through the substance of the large cerebral ganglion, and extends to the anterior pillar of the fornix.

The second is formed by small veins, which arise from the substance of the large anterior cerebral ganglion or the corpus striatum. It goes from behind forward, in the channel grooved between the corpus striatum and the thalami optici, until it anastomoses by its anterior extremity with the corresponding extremity of the choroid vein.

It is sometimes double ; the posterior then passes above the thalami optici, and usually opens into the vein of Galen.

The latter, arising from the point mentioned, proceeds directly from before backward, that is, in a direction contrary to that of the two branches which produce it, under the fornix, in the prolongation of the pia mater, which penetrates within the brain, and on that of the arachnoid membrane, which accompanies it. It generally receives, near its posterior extremity, the superior and anterior veins of the cerebellum. It opens into the anterior extremity of the right sinus, very near that of the opposite side, with which it sometimes unites to form a trunk of but slight extent, the direction of which it sometimes but not always crosses.

e. Superior veins of the cerebellum.

§ 1570. The fourth sinus also receives the superior veins of the cerebellum, that is, the posterior, for the anterior empty in the veins of Galen.

These veins, which, like the anterior, cross the transverse grooves of the cerebellum, go backward, and the anterior forward. Proceeding at first from before backward and then forward, they penetrate to the posterior part of the fourth sinus, and sometimes also into the commencement of the transverse sinus.

f. Transverse or lateral sinuses.

§ 1571. The transverse or lateral sinuses (S. transversi, s. laterales ) are the largest, and descend on each side, in the transverse groove of the occipital bone, anastomose there with the fourth sinus and also with the upper longitudinal sinus, and terminate in the foramen lacerum, in the groove of the internal jugular vein.

That of the right side usually unites, but that of the left rarely, with the superior longitudinal sinus to form a short common trunk. Sometimes also the posterior extremity of the latter passes directly between the two lateral sinuses.


ANGEIOLOGY.


355


That of the right side is most generally larger than that of the left.

We not uncommonly observe that one or even both of them is divided in a greater or less part of its course, by a transverse layer, into a superior and an inferior portion.

When this layer exists through the whole extent of the lateral sinus, the latter is completely double.

One of these two lateral sinuses is sometimes deficient. The superior longitudinal sinus then descends to the large occipital foramen, around which it turns to go to the posterior foramen lacerum.

The lateral and inferior veins of the cerebrum and the inferior veins of the cerebellum open into the lateral sinus.

The lateral and inferior veins of the cerebrum , the inferior cerebral veins, arise at nearly the centre of the skull, on the outside of the hemispheres, and usually unite in three trunks ; these are joined by a fourth, which comes from the lower face of the posterior lobe, separate from the cerebrum, go forward, and open separately from above downward at about the centre of each lateral sinus.

The inferior veins of the cerebellum, arise from the lower face of this organ, unite in two or three trunks, go backward and outward, and open from from below upward into the transverse sinus.

g. Superior petrous einu3.

§ 1572. In the place where the transverse sinus touches the posterior extremity of the petrous portion of the temporal bone, and leaves its horizontal direction to go obliquely upward, we see detached, from its outside, a much narrower sinus, the superior petrous sinus (S. pelrosus superficialis, s. superior ), which proceeds downward, inward, and forward, along the upper edge of the petrous portion of the temporal bone, where it terminates in the cavernous sinus, consequently unites this and the transverse sinus by anastomosis.

h. Inferior petrous portion.

§ 1573. The inferior petrous sinus (S. petrosus inferior, s. profundus) arises at the lower extremity of the transverse sinus, directly above the posterior foramen lacerum, from the anterior side of this sinus ; this is broader but shorter, and is situated between the anterior part of the petrous portion of the temporal bone, and the body of the occipital bone and is almost wholly situated in a fossa hollowed from the latter bone the posterior part of which is sometimes changed into a canal. This sinus proceeds from before backward and from without inward, which direction is preserved at its extremities better than in its centre ; it opens into the back part of the cavernous sinus, and establishes another large anastomosis between it and the transverse sinus.


356


DESCRIPTIVE ANATOMY.


i. Cavernous sinus.

§ 1574. The cavernous sinus (S. cavernosus ), a considerable dilatation and of a very irregular form, is situated, on each side, on the lateral part of the body of the sphenoid bone. It anastomoses posteriorly with the posterior extremities of the two petrous sinuses, forward with the coronary sinus, and backward with the anterior occipital sinus.

Its cavity has numerous soft reddish irregular filaments which intercross and are arranged in a reticular form, from whence it takes its name.

The internal carotid artery and the sixth pair of the cerebral nerves pass through it, covered by its inner membrane, which is reflected on them and unites them.

It receives superiorly the anterior and middle inferior cerebral veins, forward the ophthalmic veins, downward, on the sides, the venous branches from the dura mater.

k. Coronary sinus.

§ 1575. The coronary sinus (S. circulons, s. coronoideus ) is generally much broader anteriorly than posteriorly, and surrounds the pituitary gland. Its anterior or posterior portion is often deficient. It is sometimes also partly double, which depends on the existence of a transverse branch which passes below the gland. It receives the vein from the pituitary gland, and sometimes also the ophthalmic veins.


/. Anterior occipital sinus.

§ 1576. The anterior occipital sinus (S. occipitalis , s. basilaris anterior ) extends transversely on the posterior face of the basilar process, from the union of the two petrous sinuses on each side, and the posterior extremities of the cavernous and coronary sinuses to the corresponding point of the opposite side. It thus forms a considerable anastomosis between the sinuses of the two sides, and represents a second crown, situated below the preceding, which communicates below with the analagous sinuses of the vertebræ.

m. Posterior occipital sinus.

§ 1557. The posterior occipital sinus ($. occipitalis , s. basilaris posterior) is sometimes single, sometimes and more frequently double. In the latter case we find a right and a left. It extends from the inner extremity of the two transverse sinuses, and the external occipital protuberance, along the posterior edge of the circumference of the large occipital foramen, encircles the posterior and the lateral portions of this foramen, and anastomoses in front with the lower extremity of the


ANGEIOLOGY.


357


transverse sinus ; so that it forms a greater or less anastomosis between the lower and the upper part of this sinus.

It is sometimes double at its summit and single in the centre, but it always divides very high up, above the occipital foramen, into a right and a left portion. It is generally not very large ; but it is frequently broad, and then the transverse sinus is smaller in a direct ratio.

It sometimes but not very often replaces this sinus either on one or both sides.

In other subjects, on the contrary, we cannot trace it in the least.

§ 1578. The transverse sinuses empty through the posterior foramen lacerum into a very short common trunk, which may be termed the internal and ‘posterior cephalic vein, or the encephalic vein ( V. cephalica interna posterior, s. cephalica encephalica, s. cerebralis), and thus contrast it, according to the analogy of the arteries, to the external and anterior cephalic vein, or to the facial vein.

This trunk is situated very deeply, and descends outside of the trunk of the internal carotid artery, on the inside of the' posterior belly of the digastricus muscle. It extends from the posterior foramen lacerum to the upper edge of the larynx, where it anastomoses with the anterior cephalic vein.

It receives anteriorly the pharyngeal and the lingual veins, which generally empty separately, although they often unite with each other and with the superior thyroid vein.

II. PHARYNGEAL VEIN.

§ 1579. The pharyngeal vein (V. pharyngea) descends on the posterior and lateral part of the pharynx, and anastomoses very frequently with that of the opposite side. It is often double on one side ; in this case, one of the two most generally arises from the thyroid vein.

III. LINGUAL VEIN.


§ 1580. The lingual vein ( V. lingualis ) arises from the end of the tongue, enters between the myio-hyoideus muscle, the genio-glossus muscle, and the submaxillary gland, proceeds along the upper edge of the hyoid bone, before the hyo-glossus muscle ; thus its direction is backward, and it opens into the internal cephalic vein, either by a common trunk with the preceding, or below it.

III. INTERNAI, JUGULAR VEIN.

§ 1581. The anterior and posterior cephalic veins unite near the hyoid bone, to form the internal jugular vein ( V. jugularis internal), which might be more properly termed by analogy with the arteries, the common cephalic vein ( V. cephalica communis). This vessel descends almost perpendicularly on the anterior and lateral part of the neck, out

358


DESCRIPTIVE ANATOMY.


side of the primitive carotid artery and the pnenmo-gastric nerve, inside of the sterno-cleido-mastoideus and the omohyoideus muscles, comes to the anterior extremity of the clavicle under whieh it passes and unites with the subclavian vein, to form the trunk of the innominata.

I. SUPERIOR THYROID VEIN.

§ 1582. In this course the internal jugular vein receives some distance below the union of the external and internal cephalic veins, a vein sometimes single and sometimes double, which often forms a common trunk with the pharyngeal and lingual veins, this is called the superior thyroid vein ( V. thyroidea superior) : it corresponds exactly in its distribution to the artery of this name, but differs from it very constantly in its termination. It always empties into the common trunk of the external and internal cephalic veins. It not unfrequently divides, some distance from its insertion, into an upper and a lower branch, one of which ascends and the other descends. The superior thyroid artery, however, sometimes imitates the vein in this respect, and this anomaly frequently occurs, because it resembles the normal form of the vein.

II. INFERIOR THYROID VEIN.

§ 1583. The internal jugular vein also receives in its course, one or two inferior or middle thyroid veins ( V. thyroideœ mediœ, s. inferiores , s. descendentes), which arise from the outside of the lower half of the thyroid vein and empty higher or lower into it.

This formation is remarkable also, as the superior or the inferior thyroid artery sometimes partially or wholly arises on one or both sides, from the common trunk of the carotid arteries, and consequently resembles the normal arrangement of the veins.

IV. EXTERNAL JUGULAR VEIN.

§ 1584. The external jugular vein (V. jugularis externa) is much smaller than the internal, and forms the superficial or cutaneous vein which corresponds to the latter. It arises as high as the angle of the lower jaw, from the back side of the internal, goes outward under the parotid gland, and receives first in this place the posterior auricular vein ( V. auricularis posterior ), and then descends vertically between the platysma myoides and the sterno-cleido-mastoideus muscles, crosses the direction of the latter, and is placed on the inside of the omohyoideus muscle. Its lower portion corresponds to the inside of the sterno-cleido-mastoideus muscle, and is much deeper than the superior. It opens into the subclavian vein outside of the internal jugular vein. In order to this, it generally passes on the inside of the clavicle, but it is also sometimes reflected on this bone, from without inward.


ANGEIOLOGY.


359


Its lower extremity is often divided into two branches which ascend more or less high.

Not unfrequently that part of its upper extremity which we have before mentioned as being that by which it arises from the internal jugular vein, is only a small anastomotic branch, and the external jugular vein is so large above this point, that it receives the common trunk of the temporal vein and of the posterior internal maxillary vein, which does not enter as usual into the anterior cephalic vein.

I. SUPERIOR SUPERFICIAL OCCIPITAL VEIN.

§ 1585. The external jugular vein receives a little way below the inferior posterior auricular vein (§ 1584) the superior superficial occipital vein ( V. occipitalis superficialis superior ), which descends between the skin and the occipitalis muscle.

Next come some deeper branches, which arise from the lateral and posterior muscles of the neck.


II. INFERIOR SUPERFICIAL OCCIPITAL VEIN.

§ 1586. The inferior superficial occipital vein ( V. occipitalis superficialis superior) arises behind the superior, between the trapezius and the splenius muscle, some distance behind the external jugular vein, descends and empties into the latter at the lower part of the neck.


III. POSTERIOR AND SUPERIOR SCAPULAR VEINS.

§ 1587. Below, the external jugular vein receives posteriorly, the superior and the posterior scapular veins which accompany the arteries of the same name, and anastomose together and with the cephalic vein of the arm.


IV. ANTERIOR CUTANEOUS VEINS.

§ 1588. Before, it receives the anterior cutaneous veins of the neck, distinguished into the upper, the middle, and the lower. These veins arise from the skin and the anterior muscles of the neck, and frequently anastomose above with the inferior branches of the facial veins.

t


ARTICLE SECOND.

VEINS OP THE UPPER EXTREMITIES.

§ 1589. The blood of the upper extremities returns to the heart by the deep and the superficial veins.


360


DESCRIPTIVE ANATOMY.


I. DEEP VEINS.

§ 1590. The deep veins follow the arteries of the same name, each of which is usually attended by two veins which proceed at its sides.

II. SUPERFICIAL VEINS.

§ 1591. The superficial or the cutaneous veins are much larger than the preceding, and proceed under the skin, between it and the brachial aponeurosis.

Their roots, or the digital veins, arise principally from the back of the fingers, where we find from six to eight branches, situated at the side of one another, which frequently anastomose together. These branches also receive the largest veins which proceed along the palmar face of the fingers, which, at the height of the second or the first phalanx, leave this face to go to the dorsal.

We may refer these veins to two principal trunks, the radial vein, and the ulnar vein.


I. CATANEOUS RADIAL VEIN.

§ 1592. The cataneous radial vein, or the brachial cephalic vein (V. brachialis radialis catanea s. cephalica ), arises from the thumb and the index finger, and is called the cephalic vein of the thumb ( V. cephalica pollicis) proceeds on the back of the hand, in the space between the first two metacarpal bones, at first along the radial edge of the forearm, then along the anterior side of the arm, outside the biceps flexor muscle, passes between the pectoralis major and the deltoides muscle, and empties in the subclavian vein, below the clavicle.

II. CUTANEOUS ULNAR VEIN.

§ 1593. The cutaneous ulnar or basilic vein (V . brachialis cutanea ulnaris, s. basilica) arises from the dorsal face of the third finger, often also from all the space between the back of the index and that of the little finger, and forms, on the back of the hand, a considerable network, which anastomoses in front with the cephalic vein of the thumb. Sometimes, when it comes on the back of the carpus, it goes forward toward the radius, and anastomoses, from the lower extremity of the forearm, with the preceding, with which it always communicates on the anterior and posterior faces of the limb, by means of several large branches, which form a broad network. It almost always forms in the forearm the anterior cutaneous ulnar vein ( V. ulnaris cutanea anterior ■), and the posterior cutaneous ulnar vein ( V . ulnaris cutanea posterior), the latter being generally larger than the former.


angeiology.


361


After leaving the articulation of the elbow it ascends, under the brachial aponeurosis, on the inside of the arm, along the ulnar nerve which it covers, and empties into the lower extremity of the axillary vein.

III. MEDIAN VEIN.

§ 1594. The median vein (V. mediana) is a large branch which serves to anastomose the radial and ulnar veins and also the superficial and the deep veins of the arm. It is generally single, but is sometimes double ; its length varies, and it extends obliquely upward and backward, from the ulnar to the radial vein, as high as the flexor carpi ulnaris muscle. It generally sends one or more considerable branches, which anastomose with the anterior part of the deep brachial vein, or of the deep radial or ulnar vein. These branches are sometimes replaced by others of the cutaneous radial vein. The lower part of this vein is called the median cephalic , and its upper part the median basilic vein.

Sometimes the median vein ascends on the anterior face of the forearm, between the cephalic and the basilic vein, with which it communicates by numerous anastomoses ; it is generally termed the common median vein ( V. mediana communis).

III. AXILLARY VEIN.

§ 1595. The axillary vein ( V. axillaris) arises at the lower extremity of the axilla, from the union of the basilic with one of the brachial veins, most frequently the internal and posterior. It ascends directly before the axillary artery, receives in the centre of its course the second' vein of the arm, the external thoracic and subscapular veins, finally comes under and behind the clavicle, and is called the subclavian vein when it reaches the upper extremity of the serratus magnus muscle.

IV. SUBCLAVIAN VEIN.

§ 1596. The term subclavian vein ( V . subclavia) is usually applied to all that part of the system of the descending vena-cava which is included between the latter and the upper extremity of the axillary vein. Some anatomists, as Bichat, consider the upper part of the veins of the pectoral extremity, which extends to the scalenus anticus muscle, as also belonging to the axillary vein, and consider the subclavian vein as commencing only in this place, contrary t.o all analogy with the arrangement of the arteries. It would be more proper then to confine it to the external portion of this trunk, which extends from the upper extremity of the serratus posticus to the scalenus anticus muscle.

This proper subclavian vein receives the external jugular vein, which then empties into it (§ 1584) from below upward.

Vol. II. 46


362


DESCRIPTIVE ANATOMY.


ARTICLE THIRD.

INNOMINATA VEIN.

§ 1597. The innominata vein ( V. anonyma ) is generally known as the subclavian vein ; but it is more convenient to conform with the analogy of the arteries, and to apply to it the first term. It is formed on each side by the union of the internal and external jugular and the subclavian veins. The scalenus anticus muscle separates it from the corresponding artery ; it passes before this muscle while the artery proceeds behind it.

The left innominata vein is nearly twice as long as the right. It goes almost transversely or at least very obliquely downward and to the right, directly before and above the arch of the aorta, and above the upper edge of the sternum, leaving the sternal extremity of the left clavicle.

The right leaves the sternal extremity of the right clavicle, goes more vertically downward and to the left, unites at an acute angle with that of the left side, above the cartilages of the first rib, and thus gives rise to the descending vena-cava.

We may consider the inner third of the left subclavian vein as corresponding to the upper part of the arch of the aorta. The trunk of the descending vena-cava represents the beginning of this latter artery. The innominata vein of the right side corresponds perfectly to the innominata artery.

The innominata vein receives on each side the vertebral , the superior intercostal , the internal mammary , the superior diaphragmatic , the thymic, the superior cardiac, and the lowest thyroid veins.

I. VERTEBRAL VEIN.

§ 1598. The vertebral vein (V. vertebralis) accompanies the vertebral artery, before which it is placed. It anastomoses above with the occipital sinus, in its course from above downward and inward, by intermediate branches, with the vertebral sinuses of the neck, resumes the blood of the deep muscles of the neck by external branches, and often divides, at its lower extremity, into two roots, of which the upper emerges with the vertebral artery, through the vertebral foramen of the sixth cervical vertebra, while the lower emerges from that of the seventh either alone or at least attended only by a small arterial vessel.(l)

According toBichat, that of the right side passes before, and that of the left side behind the pneumo-gastric nerve and the subclavian artery.


(t) Eustachius, Dc ossibus, in Opp. omn., p. 191.


ANGEIOLOGY.


363


But this arrangement is by no means general. At most, the inferior root of the right vertebral vein, which passes through the vertebral foramen of the seventh cervical vertebra, usually goes behind these parts.

II. SINUSES OF THE VERTEBRAL COLUMN.

§ 1599 . The sinuses of the vertebral column ( S . columnœ vertebralis)( 1 ) are situated on the posterior face of the bodies of the vertebra, before the dura mater, are formed by two long lateral trunks and by numerous transverse anastomosing branches, which are not, like the sinuses of the skull, formed by the dura mater of the inner membrane of the veins, and which, instead of adhering intimately to the meningeal sinus, are retained between it and the bone by a loose cellular tissue.

The two trunks descend on the two sides of the posterior face of the bodies of the vertebrae, empty principally into the vertebral vein, with which they continue through the anterior condyloid foramen of the basilar bone, empty also the blood into the anterior occipital sinus, with which they communicate at least by considerable anastomoses, contract very much on the intervertebral ligaments, especially in the lumbar region, diminish singularly in caliber at the sacrum, approach each other in this place, and arise by several minute branches from the fat which surrounds the dura mater.

They anastomose together on each vertebra by several large tortuous transverse branches (circelli venosi). Hence each of these bones has a proper venous crown, similar to that at the base of the skull, and corresponds finally to the whole venous system of the interior of the skull, and opens externally into the adjacent veins, between each pair of vertebra.

The two longitudinal trunks are also united at their inferior extremity by a large transverse posterior branch, which corresponds to the anterior transverse branch of the coronary sinus of the skull (§ 1575 ).

These trunks anastomose outwardly with the posterior branches of the vertebral, intercostal, lumbar, and sacral veins, through the intervertebral foramina. The transverse branches receive anteriorly numerous branches, which come from the substance of the bodies of the vertebras, and posteriorly those which arise from the dura mater.

The branches which enter the external veins, which we have mentioned first, carry outward the blood which the sinuses of the vertebral column have received from the dura mater and from the vertebra.

From this description it follows that each vertebra, consequently also each corresponding section of the spinal marrow, particularly in the early periods of life when the spinal cord occupies the whole vertebral column, has its proper venous system, and that all these systems anastomose together and form a chain of rings.

(I) G. Breschet, Essai sur les veines du rachis, Paris, 1819.


364


DESCRIPTIVE ANATOMY.


III. SUPERIOR INTERCOSTAL VEIN.

§ 1600. The superior intercostal vein (V. imtcrcostalis supremo) is almost as large as the azygos vein (§ 1605), is much larger on the left than on the right side, and is often only a branch of the vertebral vein. When it is distinct and separate from the latter, it empties from below upward into the trunk of the innominata. Its roots extend below the eighth rib. It arises from the intercostal spaces, the left lung, the left bronchial vein, the esophagus, the aorta, &c., and anastomoses by its lower branches with the right and left azygos veins, unites to the first, and always proceeds at the left side of the second. It is as much longer as the left azygos vein is shorter, and resembles the right azygos vein as the branches of anastomosis between it and the left are larger. It proceeds downward, along the vertebral column, behind the pleura.

§ 1601. The internal mammary vein, the superior diaphragmatic vein, &c., correspond precisely to the arteries of the same names. The lowest thyroid vein alone differs.

IV. LOWEST THYROID VEIN.

§ 1602. The innominata veins receive from above downward, usually on the right and left, or at least on one side, the lowest thyroid vein (V. thyroidea ima ). The right is nearer the outer extremity of the right innominata vein than the left is to that of its own ; and the latter almost corresponds to the median line, while the other is thrown still more to the right, although the latter arises from the left lobe of the thyroid gland.

Its constant existence deserves attention, because the lowest thyroid artery, which is not common, is a repetition of it.

CHAPTER III.

TRUNK OF THE SUPERIOR VENA-CAVA.

§ 1603. The superior or descending vena-cava ( V . cava superior , s. descendens ) is formed by the union of the two innominata veins, a little above the arch of the aorta, near the cartilage of the first rib on the right side. Thence it descends to the upper and right part of the right ventricle. Its direction is nearly vertical, a little oblique however from right to left and from behind forward. It proceeds on the right side of the aorta, and it is inclosed for the space of about two inches in the sac of the pericardium. Its upper part is loose and covered on the right b} r the summit of the right lung, on the left by the aorta, backward by the right superior pulmonary vein, forward by the cartilage of the upper eighth rib of the right side. It is situated entirely on the right.


ANGEIOLOGY.


365


§ 1604. This is its usual arrangement; but sometimes, although very rarely, we find two descending venæ-cavæ, and then the two trunks of the innominata vein are not united. We have before us two instances of this anomaly, which has been mentioned also byBœhmer,(l) Murray, (2) and Niemeyer.(3) In this case the right descending venacava descends before the aorta, turns backward and outward around the left auricle, comes on the lower face of the heart, goes forward in the circular groove, reaches the right auricle, and opens into its lower and posterior part.

This anomaly is very curious, on account, of its analogy with what is seen in several mammalia and in several reptiles.

CHAPTER IV.

AZYGOS VEIN.

§ 1605. The descending vena-cava receives no branch in the pericardium: at least it is extremely rare that the azygos vein empties into it within the pericardeal sac. (4)

But directly after leaving the pericardium, it receives at its posterior part, the azygos vein ( V . azygos , s. sine pari), which opens still more rarely into the right auricle than into that portion of the vena-cava enveloped by the pericardium, and it more frequently opens into the venacava much higher than usual.

This vessel forms a large anastomosis between the descending and the ascending vena-cava, for it arises from the latter by numerous branches, and empties into the former.

It does not perfectly deserve its name, since we find on the left side also a vessel which corresponds to it, the small semi-azygos -vein (F, hemiazygos) : this latter does not however extend as high.

In the cases where this vein is thought to be doubled, (5) there is no new and unusual trunk, but generally, only a simple change in respect to capacity. This second azygos vein, which always exists on the left side, is only ah extraordinary development of the left superior intercostal vein, which constantly anastomoses by considerable branches with the right and left azygos veins. In this case there is only a diminution, a contraction of the branches which anastomose between the common left and the right azygos vein, and likewise between the latter and left superior intercostal vein, with a considerable increase of the left azygos vein, whence a trunk is formed which occupies the left side, but Avhich always,, empties into the corresponding subclavian vein at the usual place. •

(1) De confluxu triarum venarum cavarum, Halle, 1763.

(2) Neue Schwedische Abhandlungen, vol. ii. p. 286.

(3) DefÅ“tu ; puellari difformi , Halle, 1814.

(4) Cheselden, Phil. TV., No. 337.

(5) See our Handbuch der pathologischen Anatomie, vol. ii. p. ii, p. 127.


366


DESCRIPTIVE ANATOMIC,


We have sometimes observed, in a similar case, a very curious formation, the insertion of the right azygos vein much higher than usual, and once even in the trunk of the vena-innominata of the right side.(l)

This greater development of the left azygos vein, and its union with the left upper intercostal vein in a common trunk are not rare, but the lateral insertion of this vessel is much less common ; here the right azygos vein empties into the left, which is much larger, and its trunk does not terminate in the descending vena-cava, but in the left subclavian vein. (2)

The azygos vein arises below on the' two sides, by considerable branches, either directly from the ascending vena-cava, or from the renal or the first lumbar veins, most generally by several of these vessels at once.

The trunks formed by the union of these branches, the right and the left, the former of which is the proper, or rather the right azygos vein, and the latter the semi-azygos, or more properly the left azygos vein, pass, sometimes with the aorta through its opening, sometimes more outwardly, through the diaphragm.

The trunk of the right side proceeds forward and to the right on the side of the esophagus, before the right intercostal arteries, on the anterior face of the vertebral column. It receives behind and on the right the ten or eleven inferior intercostal veins, of which the inferior ascend, the central are transverse, and the superior descend. Two or three of the latter generally unite in a single trunk. They all proceed below and before the intercostal arteries.

The right azygos vein receives anteriorly the esophageal and the right bronchial veins.

It receives on the left side, and nearly upon the seventh or the eighth dorsal vertebra, the semi-azygos or the left azygos vein, which passes behind the thoracic canal and on the vertebral column to come to it, after receiving the five or six inferior intercostal veins.

This left azygos vein is sometimes double ; when this is the case, another, which is superior and smaller, anastomoses with it, and empties into the right azygos vein, when the superior left intercostal vein is smaller than usual.

The right azygos vein anastomoses, by transverse branches, on the anterior face of the bodies of the vertebrae, with the superior intercostal vein.

Similar anastomoses exist also between it and the left trunk, so that the formation of the venous system on the anterior face of the bodies of the vertebrae resembles that on their posterior face.

(1) Wrisberg has once observed the same thing ( loc . cit., vol. i. p. 136.) This arrangement of the right azygos vein does not necessarily exist whenever the left is unusually developed.

(2) We have seen this case once. Wrisberg is the only author (loc. cit., obs. iii. p. 142-145) who mentions it.


ANGEIOLOGT.


367


CHAPTER V.

VEINS OF THE LOWER EXTREMITIES.

§ 1606. The veins of the lower extremities like those of the upper extremities, are divided into deep and superficial veins.

I. DEEP VEINS.

§ 1607. The deep veins which accompany the arteries, and with which they are closely connected on both sides, are double almost to the knee, but in such a manner that the two synynomous veins already unite with each other at some distance from then: upper extremity. After leaving the ham they are single.

I. POPLITEAL VEIN.

§ 1608. The popliteal vein ( V. poplitea) is single, and arises from the union of the anterior and posterior tibial and fibular veins ; it is situated backward and a little on the outside of the popliteal artery. It is more superficial than this artery, and intimately adheres to its parietes.

II. CBURAL VEIN.

§ 1609. The superficial crural vein (V. femoralis superficialis), by which term the preceding vein is designated, after it passes through the tendon of the adductor magnus muscle, comes on the inside of the crural artery, which partly covers it ; it is then situated more deeply than this artery.

III. DEEP CRURAL VEIN.

§ 1610. The deep crural vein (V. femoralis profunda) is generally more superficial than the artery of the same name.

IV. COMMON CRURAL VEIN.

§ 1611, The superficial and the deep crural veins unite and give origin to the common crural vein (V. cruralis s. femoralis communis), which is situated more inward and backward, and consequently more deeply than the corresponding artery. It is placed on the inside of this vessel, and is separated from it by the crural nerve. It passes under the crural arch to enter the abdomen.


368


DESCRIPTIVE ANATOMY.


II. SUPERFICIAL VEINS.

§ 1612. There are two superficial veins called the saphena (V. saphena,), which carry back the blood from the skin of the lower extremities. They are distinguished into external and internal.

I. INTERNAL SAPHENA VEIN.

§ 1613. The internal saphena vein ( V. saphena , s. saphena interna, s. magna , s. cephalica pedis ) ' arises by a deep branch, situated below the layer of cellular substance, from most of the inside of the toes, like the superficial veins of the arm, and is composed on the back of the foot of several branches, which form a considerable network ; it proceeds forward and backward along the internal and upper part of the tarsus, passes from the internal malleolus to the internal and anterior part of the leg, thus comes behind the inner condyle of the femur, then goes to the inside of the thigh, ascends along its inferior part before the gracilis or the adductor longus muscle, passes through the fascia lata aponeurosis, about one inch below the crural arch, and empties outward and backward into the common crural vein.

A second branch which is more superficial, and situated directly below the skin, arises from the inner and anterior part of the leg, sometimes also only ’ from the inside of the tibio-tarsal articulation, often anastomoses with the preceding in this place, ascends on the anterior internal side of the thigh, and unites with the preceding, directly below its confluence with the crural vein. There it receives the superficial internal crural vein, and also most of the external pudic and subcutaneous abdominal veins, which descend outward to come to it.

II. EXTERNAL SAPHENA VEIN.

§ 1614. The external saphena vein ( V . saphena externa) is much smaller than the internal with which it communicates at its origin. It arises on the outside of the back of the foot, goes backward and upward under the external malleolus, approaches the tendo Achillis, reaches the centre of the posterior part of the summit of the leg, is situated in the ham on the inside of the tibial nerve, and empties a little above into the popliteal vein.

HI. EXTERNAL ILIAC VEIN.

§ 1615. The external iliac vein (F. iliaca externa, s. anterior ) is the direct continuation of the common crural vein, (§ 1612) and ascends behind and on the inside of the external iliac artery and along the iliacus internus muscle. At its lower extremity it receives the epigastric and the circumflex iliac veins.


ANGEIGLOGY.


369


IV. HYPOGASTRIC VEIN.

§ 1616. The hypogastric vein ( V. hypogastrica, s. iliaca posterior, s. inferior) arises by branches which correspond to those of the hypogastric artery, from the external and internal parts of the pelvis, consequently from the glutei muscles, the genital organs, the bladder, and the lower part of the rectum. The umbilical arteries which are the continuation of the hypogastric trunk in the fetus, alone have no corresponding vein, as the umbilical vein goes to the liver.

The twigs are here very considerable in proportion to the branches, so that these vessels form plexuses, which are termed according to the parts whence they arise, the hemorrhoidal plexus {plexus hemorrhoidalis),ih.einternalandexternalpudicplexus (P . pudendalis internus et externus ), the vesical plexus (P. vesicalis ), the sacral plexus (P. sacralis), the vaginal plexus (P. vaginalis), and the uterine plexus (P. uterinus).

V. PRIMITIVE ILIAC VEIN.

§ 1617. The external iliac and hypogastric veins unite to form a short trunk called the primitive iliac vein ( V. iliaca primitiva , s. communis). This trunk proceeds from below upward, and from without inward. It unites at an obtuse angle with that of the opposite side, on the anterior face of the fifth lumbar vertebra, and on the right to form the ascending vena-cava.

The right trunk is shorter than the left, exactly as the common trunk of the subclavian and jugular veins on the right side, a little less so however than the latter. It also ascends a little more vertically.

The right is placed behind and outside of the primitive iliac artery, the left behind and on the inside of this artery, before which its upper part passes.

These two trunks always unite below and on the right of the bifurcation of the primitive iliac artery, so that the upper part of the left primitive iliac vein is situated below the commencement of the right primitive iliac artery.

CHAPTER VI.

ASCENDING VENA-CAVA.

s

1618. The inferior or ascending vena-cava {vena-cava inferior , s. ascendens) extends from the fourth or the fifth lumbar vertebra, to the lower part of the right amide. It is always much larger than the superior. In its whole course, it is situated on the right of the vertebral column, at the side of the aorta which is partly covered by it.

Below and in most of its extent, it proceeds perpendicularly upward, but its upper part inclines to the right, so that it there takes an oblique

Vol. II. 47


37a


DESCRIPTIVE ANATOMY.


direction. This part is situated in a particular depression of the posterior edge of the liver, sometimes even it is surrounded entirely by the substance of this gland, from which it can be easily separated.

Directly below the liver, it passes through the square opening of th diaphragm, enters the chest, and opens there directly from below upwards, into the right auricle.

§ 1619. This is the common arrangement of the ascending venacava.

The anomalies it presents, relate to the number , the situation , and the insertion of the vessel.

1st. A rare anomaly is where the ascending vena-cava divides into two trunks ; it presents several degrees.

The least anomaly seems to be that where the left side of the ascending vena-cava gives off, a little below the renal veins, a vessel which ascends behind the aorta to go to the left renal vein, with which it anastomoses, so that these two veins form around the trunk of the aorta a plexus, whence arise all the renal veins of the corresponding side.

We have seen this arrangement several times. In fact there seems then to be a double renal vein ; but when we consider that this vessel passes behind the aorta to empty itself into the upper renal vein, and when we regard the following series of anomalies, we cannot but consider it as indicating the doubling of the trunk of the ascending venacava.

We sometimes see too, in the place where the ascending vena-cava arises from the confluence of the two primitive iliacs, an accessory vessel which varies in size, and ascends on the left of the aorta, and opens either into the vena-cava or into the left renal vein.(l)

When the division is more marked the two trunks which proceed on the right and the left of the aorta are still more similar. Zimmermann, (2) Wilde, (3) and Pætsche,(4) have described cases of this kind The division always commenced as high as the renal veins, and the two trunks anastomose together, on the fifth lumbar vertebra, by a small transverse branch.

The division of the ascending vena-cava into two trunks more rarely depends on the fact that the hepatic veins do not unite with it. The first degree of this anomaly is where the hepatic veins open into the ascending vena-cava higher than usual, above, and not below, the diaphragm, as Huber(5) and Morgagni(6) have observed. It exists in the highest possible degree when the trunk of the hepatic veins empties the blood into the right auricle. (7)

(1) Morgagni, Dc.sed. el. cans, morb., tp. 47, a. 30. — Peh!, De venar. var., 1773. —We have seen this anomaly several limes.

(2) Dc notanclis circa naturcc h umanœ machinœ lusis , Duisburg, 1750, p. 54, 55.

(3) Comm. Petrop.. vol. xii. p. 312, vol. viii. fig. 1-2.

(4) Sylloge, obs. an., in the Hall. coll, dis., vol. vi.

15) Obs. anat ., Cassel, 1760, p. 34.

rfj) De sed. et caus. morb., ep. 60, a. 6.


ANGEIO.LOGY,


371


All these anomalies are remarkable, as they establish an analogy between man and most reptiles and fishes, and also between the abdominal and the thoracic veins.

2d. The ascending vena-cava exists sometimes on the left, and not on the right side of the vertebral column, not only where the viscera generally are inverted, but even when the latter case does not exist. ( 1 )

3d. The anomaly is greatest when the vein opens into the left auricle, (2) which depends on the development being arrested.

§ 1620. The ascending vena-cava receives the lumbar , the spermatic, the splenic , the capsular , the inferior diaphragmatic, and the hepatic veins.

I. LUMBAR VEIN'S.

§ 1621. There are three or four lumbar veins (V. lumbares ) which correspond to the lumbar arteries and empty into the ascending venacava. The left, which pass behind the aorta, are longer than those of the right. All anastomose with each other, and with the vertebral sinuses, through the intervertebral foramina (§ 1599).

II. SPERMATIC VEINS.

§ 1622. The spermatic veins (V. spermaticce ) usually open the right into the anterior part of the ascending vena-cava, some distance below the right renal vein ; the left opens more externally than the preceding into the left renal vein.

These veins, particularly the left, are divided at a greater or less distance from their union, an arrangement remarkable as being a greater development of the type of the left side. Hence results a plexus called the corpus pampiniforme.

III. RENAL VEINS.

§ 1623. The renal or emulgent veins ( V. renales emidgentes ) are usually single, and are numerous more rarely than the arteries, even where the latter vary. They are situated also farther forward than they.

The left is much longer than the right. It arises higher than it, opens into the vena-cava at more of a right angle, and usually passes before the aorta to go to it.

We not unfrequently find it behind the aorta, (3) an anomaly, to which that leads where the vein divides into an anterior and a posterior trunk, which pass, the latter behind, the former before the aorta, beyond which they are frequently again blended into one,

(1) Morgagni, Ep. anat., m. 56, a. 31.

(2) Ring, in the Med. and phys. journ., vol. xiii, p. 120.— Lemaire, in the Bull, des sc. mêd., vol. v. 1810.

(3) Albinas, Annot. acad., b. vii. c. 2.— Sandifort, 05«, an. path., b. i. c. 5 ; b, iv. c. 8.

We have often seen this anomaly.


372


DESCRIPTIVE ANATOMY


IV. CAPSULAR VEINS.

§ 1624. The capsular veins (V. capsulares) open, the right almost always into the ascending vena-cava, the left, on the contrary, into the left renal vein, nearly about its centre.

V. HEPATIC VEINS.

§ 1625. We may distinguish the hepatic veins (V. hepatic«) into large and s'mall.

The small are more numerous than the large. They empty into that portion of the ascending vena-cava, which ascends behind the liver, and are arranged irregularly in pairs one at the side of another. We number about twelve.

The large are much larger. They emerge from the posterior edge of the liver, much nearer its upper than its lower face, and empty into the anterior part of the vena-cava, directly below its passage through the square opening of the diaphragm.

There are usually two which open into the vena-cava near each other.

The right is smaller, and almost always a little deeper, and belongs entirely to the right lobe.

The left is much larger, especially in the fetus, and divides directly below its insertion into the ascending vena-cava, into two trunks, of which the right belongs to the inner part of the right lobe, and the left to the left lobe only.

VI. INFERIOR DIAPHRAGMATIC VEINS.

§ 1626. The inferior diaphragmatic veins ( V. phrenicœ inferiores) accompany the arteries of the same name, and empty either into the large hepatic veins or enter into the vena-cava, directly before it passes through the diaphragm.


CHAPTER VII.

SYSTEM OF THE VENA PORTA.

§ 1627. The vena porta (V. portarum)(l), an extremely curious phenomena in the organism, is a small separate system, inclosed in the large, the roots of which arise from the intestinal canal, where it communicates with the system of the aorta by branches of the visceral and mesenteric veins, and which are distributed, like arteries, in the

(1) Walter, De venä port, exerc. anat ., Leipsir, 1739, Exerc. anat ., vol. ii. 1740. — Hœnlein, Descriptiovenæ portarum, Frankfort, 1809.


ANGEIOLOGY.


373


liver, where it unites by means of the hepatic veins (§ 1628) in the venous system of the body.

It is very unfrequently directly continuous with the venous system of the body, and then it does not ramify in the liver, but empties directly into the ascending vena-cava, of which it forms a ramification^ 1) In this case the hepatic artery is larger than usual.

1. VENOUS PORTION.

§ 1628. The venous portion of the vena-porta is formed principally by three large trunks, the coronary vein of the stomach, the splenic and the mesenteric veins, which unite to produce the middle part or the trunk of the vena-porta.

I. CORONARY VEIN OF THE STOMACH:

§ 1629. The coronary vein of the stomach ( V . coronaria ventriculi superior) corresponds to the artery of the same name. It is the smallest of the three branches. It empties from left to right, and from above dow’mvard into the trunk of the vena-porta, behind the piloric portion of the stomach. The constancy of its separation with the two other veins seems to be the cause why the cœliac artery divides so frequently into several trunks.

II. SPLENIC VEIN.

§ 1630. The splenic vein (V. splenica ) not only takes up the blood from the spleen, the omentum, most of the- stomach, the pancreas, and the duodenum, but receives also, shortly before it terminates, the last epiploic vein, and thus corresponds to the inferior mesenteric artery, so that consequently this latter is a subordinate trunk.

III. MESENTERIC VEIN.

§ 1631. The mesenteric vein ( V . mesenterica , s. mesaraica ) receives the veins of the small intestine, of the ascending and transverse colon. Consequently, it corresponds to the superior mesenteric artery. In the early periods of fetal existence, it receives the omphalo-mesenteric vein, which arises from the umbilical vesicle and commonly disappears at the third month of pregnancy.

(1) These cases are extremely rare. We know of but four instances, only two of which are authentic. Lieutaud mentions one of the first class from Bauhin, (Hist, anat. meet ., vol. i. p. 190), and Huber mentions another ( obs . anal., p. 34) ; but perhaps he means the trunk of the hepatic veins, which is probable. The authentic instances have been mentioned by Abernethy (Ph. XV., 1793, vol. i. p. 59-63), and Lawrence (Med. ch. tr., vol. v. p. 174). These anomalies are very important in the history of the secretion of bile, and likewise for the theory of the primitive part of the venaporta, and because they establish an analogy with the invertebral animals.


1374


DESCRIPTIVE ANATOMY.


II. TRUNK AND ARTERIAL PORTION OF THE VENA-PORTA,

§ 1632. These last two branches, in uniting at a right angle, form the trunk of the vena-porta, the walls of which are thicker than those of its venous portion. This trunk proceeds obliquely upward to the right, behind the second curve of the duodenum, having in front the hepatic artery, the biliary ducts, the lymphatic glands, and the hepatic plexus, with which parts it is united by a common envelop, which comes from the peritoneum, the capsule of Glisson ( capsula Glissonii). It ascends before the vena-cava, and is much larger than it. Near the right extremity of the transverse fissure of the liver, it divides at an acute angle into from two to five branches, of which the right is larger and shorter, goes directly to the right lobe of this gland, while the left is smaller and longer, proceeds transversely in the fissure, and enters into the left lobe.

The latter, in the fetus, receives the umbilical vein, and gives off posteriorly the venous canal, which goes into the ascending vena-cava. These two vessels will be mentioned in the history of the fetus.

In describing the liver, we shall mention the distribution of the arterial portion of the vena-porta.


SECTION IY.

PULMONARY ARTERY.

§ 1633. The pulmonary artery (A. pulmonalis, s. vena arteriosa) is generally a little smaller than the aorta, and arises from the summit or apex of the right ventricle, ascends to the left and backward, and presents a convexity upward and forward on the right, while it is concave downward and backward to the left. At its lower part it covers the commencement of the aorta in front, and in the rest of its course it proceeds on the left side of this artery, below its arch and on the left of its trunk. After passing through about two inches, it divides into a right and a left branch. From its bifurcation arises a round solid cord, a line thick and about four lines long, called the arterial ligament ( L . arteriosum). This is the remains of a duct, the arterial canal, or canal of Botal ( ductus arteriosus, s. Botallianus ), or the right root of the aorta, the changes of which we shall describe more minutely when giving the history of the fetus. This cord ascends a little obliquely to the left, toward the commencement of the ascending aorta, and is attached to its anterior part so firmly that it cannot be separated without tearing. A cylinder of bone, more or less apparent, generally forms within it, even in young people, shortly after the canal is completely effaced, in accordance with this general law, that ossification marks a diminution of the vital activity in the organs.


ANGEIOLOGT.


375


The two branches separate from the trunk at a right angle, to go each to its corresponding lung.

The right branch proceeds transversely to the right, directly behind the aorta and the descending vena-cava, before the right bronchia. It is not only larger than the left, which depends on the greater size of the right lung, but it is also longer than it by the whole breadth of the aorta. It also penetrates more deeply into the fissure of the lung, and divides from above downward, before coming to the substance of the organ, into two branches, an upper, which is smaller, and the inferior, which is much larger.

The upper branch goes upward, and at the moment it enters the lung, divides again into two ramuscules, of which the lower is also the larger, while the upper bifurcates in turn.

The lower branch descends behind the superior pulmonary vein, to arrive at the middle and inferior lobes of the lung. It divides, opposite the middle lobe, into two branches, an anterior and superior, which bifurcates also before it enters the most internal part of the middle lobe, the other is much larger and lower, and, covered at first before by the middle branch of the right bronchia, goes to the lower lobe, and divides into three branches before it penetrates into it.

The left branch of the pulmonary artery is shorter and narrower, ascends a little on the left, goes toward the left lung, passes before the origin of the descending aorta, goes outward in the fissure of this lung, between its upper and its lower lobe, and divides into upper and lower branches. Those of its branches which arise the first, the posterior, are generally smaller than the anterior, which arise afterward ; and those which ascend into the superior lobe are smaller but more numerous than those which descend into the lower. All generally bifurcate when they enter this organ.

The two branches of the pulmonary artery and all their ramifications are situated above and before the bronchia and their subdivisions.

§ 1634. The congenital anomalies of the pulmonary artery are,

1st. The total absence.

2d. Its obliteration.

3d. A great narrowness.

4th. Its insertion in the aorta : then it sometimes forms only one trunk, and sometimes its two principal branches arise from two separate places.

5th. Its insertion in the left ventricle.

6th. Its insertion in the two ventricles by the perforation of the base of the interventricular septum.

7th. The existence of two or four valves, instead of three.

Sth. The permanence of the arterial canal.

9th. The insertion of this canal in the subclavian vein.

10th. Finally, the insertion of this canal in the right ventricle.


376


DESCRIPTIVE ANATOMY.


SECTION Y.

PULMONARY VEINS.

§ 1635. The pulmonary veins (V. pulmonales , s. arteriœ venosœ) are usually destitute of valves, with some very rare exceptions.(l) They generally form on each side an upper and a lower trunk, which open at the four angles of the right auricle (§ 1308), and which, considered together, are a little smaller than the trunk of the pulmonary artery. The upper veins are a little larger than the lower, and are somewhat more distant from each other when they arrive at the auricle. Those of the same side are much nearer each other than those of the two sides. They are looser anteriorly than posteriorly, and are placed in front of the branches of the pulmonary artery and of the trachea. After proceeding a short distance, from four to six lines, each trunk, the inferior generally sooner than the superior, divides anew into at least two principal branches, viz. the upper into an upper and a lower branch, the lower into an anterior and a posterior branch, which commonly directly subdivide into two or more branches, before even penetrating into the fissure of the lung.

The right pulmonary veins are a little larger, but most generally much shorter than the left. They are always covered anteriorly by the descending vena-cava and also by the right auricle. The upper vein of this side comes from the upper and middle lobes of the right lung, from the first by its upper branch and by its lower branch from the second. The upper branch however usually receives one or more ramifications from the middle lobe, while the lower receives them only from the inferior lobe. The distribution of the pulmonary veins is then the opposite of that of the artery.

§ 1636. We not (infrequently find a greater(2) or less(3) number of trunks of the pulmonary veins, either from their division or their union. The first anomaly seems to be more common than the second. It does not always occur exactly in the same manner, and differs in quantity and quality. Most generally the number of trunks is increased by one only, there being five. In two cases now before us, the anomaly exists on the right side : the three trunks are situated one above another : the central trunk is much smaller than the other two, and is placed directly below the superior, being nearer to it than to the lower. We then observe in this only a greater development of the normal type.

(1) Kelch (Beytrœge zur path, anat., Berlin, 1813, p. 81, No. 59) has found, before the orifice of one of the right pulmonary veins, a valve, which is very curious, as a repetition of what occurs normally in several reptiles.

(2) Meckel, Mém. de Berlin, 1750, p. 167. — Haller, De part. corp. hum., f. i. f. ii. p. 123. — Portal, Mim. de Paris, 1771, Hist., p. 74. — Sandifort, Obs. anat. path., vol. iii. p. 41; vol. iv. p. 91.

(3) Loeseke, Obs. anat., Berlin, 1754, p, 26. — Portal, Mem.de Paris, loc. cit. — Haller, loc. cit. — Pohl, De vcnis, Leipsic, p. 1 1.— Sandifort, Obs. anat. path., book iii. p. 18.


ADENOLOGV .


377


Less commonly we find a third trunk, which we have observed also on the left side, and which, proportionally smaller than the usual supernumerary vessel, arises by branches coming from the posterior part of the upper and lower lobes, is separated from the right superior pulmonary vein by the right branch of the pulmonary artery, and empties from above downward and from behind forward, into the posterior part of the right portion of the pulmonary auricle, almost opposite its centre.

Still more rarely also the number of pulmonary veins is increased by two, and becomes six ; there are then sometimes three on each side, and sometimes four on one side and two on the other.(l) We regret that Sandifort did not state on which side the anomaly existed in the latter case.

The pulmonary veins seem to be diminished on the left side more frequently than on the right ; at least this diminution has been observed on this side by Loeseke, Sandifort, and ourselves, while the veins on the right side were normal.

Other anomalies of the pulmonary veins, such as the termination of all or of one only, in the descending vena-cava or in the right auricle, are much more rare.


SECTION VI.

LYMPHATIC SYSTEM.

§ 1637. We have already mentioned the general characters of the lymphatic vessels, in the first volume : they accompany the two sections of the vascular system already described, particularly the veins, which they resemble much more than the arteries in their arrangement, and correspond to them so exactly, that their history is already partially given in that of the sanguineous system. The topography of the lymphatic system is generally stated without any regard to the difference of the two principal parts which compose it, the vessels and the glands. But the method adopted by some anatomists, among others by Cruickshank and Bichat, and which is to desciibe first the glands and then the vessels, is preferable. We also have adopted it, because, by insulating the history of the glands, we can not only present a more general picture of the distribution of the lymphatic vessels, but can form more exact ideas of the most essential particulars presented by the glands, in respect to their existence, number, situation, and size, in different parts of the body.

Authors are not agreed as to the order of describing the lymphatics. Some, as Scemmerring and Portal, examine first those of the head, next those of the limbs, finally those of the thoracic and abdominal cavities and of the parts they contain. Others again, as Hewson and Cruik

(1) Sandifort, Obs. anat. path., book iii. p. 41, book ir. p. 91.

Vol. II, 48


378


DESCRIPTIVE ANATOMY.


shank, regard only the position, and begin with the lymphatics of the lower limbs, then pass to those of the abdomen and chest, and terminate by those of the upper extremities and of the head. Many, of whom we shall mention Mascagni and Bichat, whose method resembles the preceding very much, describe the lymphatics according to the relations between them and the principal trunk ; so that they divide them first into two large sections, comprising, first, those which communicate with the thoracic canal within the abdomen and the chest, second, those which open in the neck, either in this canal or directly into the subclavian and jugular veins.

Although the method of describing the lymphatic vessels of the lower limbs is preferable, because we can then commence with the most considerable part of the system, and particularly because it allows us to state beforehand the origin of the principal trunk, whence it is generally followed in treatises, it seems to us more convenient, in a complete treatise on anatomy, to examine these vessels in the order in which we have described the other sections of the vascular system ; and consequently, as we take the history of the arteries as the base of that of the other vessels, to treat, first of the lymphatic vessels of the head and neck, then those of the upper extremities, next those of the viscera of the chest and of the abdomen, and lastly those of the lower extremities. By this method we finally arrive at the principal trunk, and the description follows the same course as the lymph does in the system.


CHAPTER I.

LYMPHATIC GLANDS.

I. LYMPHATIC GLANDS OF THE HEAD AND NECK.

I. LYMPHATIC GLANDS OF THE HEAD.

§ 1638. The lymphatic glands of the head are, proportionally speaking, very small and very few. They have not as yet been demonstrated strictly to exist within the skull, either in the brain or in the parietes. At least we cannot consider certain tumors, as those of scrofula, which are not unfrequently found in greater or less quantity in the substance or on the surface of the brain, as proving that lymphatic glands exist in this viscus;(l) for we have no proof that these tumors arise from enlarged glands and are not new formations.

We cannot assent to the opinion that the pituitary and pineal glands are lymphatic glands.

Those formations called glands of Pacchioni and the other analogous corpuscles which appear in the choroid plexuses are very different


(1) Reit, Manor, clin., vol. îi. f. 1, p. 39.


ADENOLOGY.


379


Those small bodies found in the carotid canal, and which are lymphatic glands, according to 6ome anatomists, as Winterbottom(l) particularly, seem to us to be the upper ganglions of the great sympathetic nerve. We have formed this opinion after frequent examinations of them.

§ 1639. On the contrary there are evidently lymphatic glands on the outside of the head. They are much more rare in the cranial than in the facial portion. In fact, in the skull they exist only at the lower part, behind the ear ; even there they are not constant and very small.

They are more numerous in the face. They are found also at its lower part, under the zygomatic arch, and around the parotid gland in all its extent. The superficial glands cover the outer face of this gland ; the deep glands are situated on the buccinator muscle and behind the parotid gland. We also find very constantly within this gland one or more, which are small and almost, either alone or with those near them, the primitive seat of those tumors which are generally considered, but very wrongly, as developed in the substance of this gland. (2)

The largest and most constant of these glands are situated along the lower edge of the lower maxillary bone, on the anterior part of the inferior belly of the digastricus muscle.

II. LYMPHATIC GLANDS OF THE NECK.

§ 1640. The lymphatic glands of the neck are distinguished into superficial and deep.

The superficial are smaller and less constant than the rest, and are found along the external jugular vein, between the platysma myoides and the sterno-cleido-mastoideus muscles.

The deep glands are much larger and more numerous ; this region contains more than any other excepting the mesenteric.

There are none in the anterior part of the neck nor in the middle part of its lateral face, or we find at least only two or three of them which are small, which are not larger than a seed of hemp, and which are situated on the sides of the larynx, and between it and the hyoid bone. One or several of them are found on the mucous membrane of the trachea and of the esophagus imbedded in a great quantity of fat. They sometimes swell very much, and then may cause suffocation.(3)

The lymphatic glands are small and inconstant also on the posterior part of the neck.

The largest and most numerous are those in the upper and in the lower part of the lateral faces of this region of the neck.

The upper and anterior ( G . concatenate , s. jugular es), which are the largest, extend under the sterno-cleido-mastoideus muscle, from the

(1) De vasis absorbentibus, Edinburgh, 1781.

(2) Burns, Surgical anatomy of the head and neck.

(3) Burns, loc. cit., p. 85, tab. 5.


380


DESCRIPTIVE ANATOMY.


mastoid process, along the carotid artery and the internal jugular vein, to the upper extremity of the cavity of the thorax. Some are placed outward, before the carotid artery, others inward, between this artery and the vertebral column. The most and the largest of these glands are found at the upper part of the neck, where the large vascular trunks divide.

The nearness of the carotid artery renders it possible to confound the tumors produced by their enlargement with an aneurism.(l) These tumors derange respiration and digestion because they compress the great sympathetic and pneumo-gastric nerves.

When the glands behind the large vessels swell, they usually embrace these trunks, and also the nerves, and are blended with them in a single mass.

The inferior and posterior are usually smaller. They are surrounded with a very loose cellular tissue ; they occupy the triangular space between the sterno-cleido-mastoideus muscle, the clavicle, and the trapezius muscle, and frequently extend to the axillary glands, along the vessels of the shoulder.

II. LYMPHATIC GLANDS OF THE UPPER EXTREMITIES.

§ 1641. The lymphatic glands of the upper extremities are divided into the brachial and the axillary.

I. BRACHIAL GLANDS.

§ 1642. The brachial glands rarely exist below the humero-cubital articulation. We however sometimes find several on the course of the radial and ulnar vessels, but they are few and very small.

The glands of the elbow are situated on the anterior face of the arm, especially on that of the inner condyle of the humerus. They vary in number from one to four.

From the elbow to the axilla are from four to seven, placed successively on the inner and anterior side of the arm, along the superficial brachial artery.

II. AXILLARY GLANDS.

§ 1643. The axillary glands in number and size exceed the preceding : we number as many as twelve which surround the large trunks of the vessels. They exist principally between the serratus magnus and the pectoralis minor muscles and the internal part of the vascular trunks, to which they are sometimes very intimately united, but extend below the pectoralis major muscle and the clavicle.


(1) Burns, loc. cit., p. 81


ADENOLOGY.


381


The deepest are the largest, and are covered by the pect oralis minor muscle.


III. LYMPHATIC GLANDS OF THE TRUNK.

§ 1644. The lymphatic glands of the trunk are divided into those of the thorax and those of the abdomen.

I. LYMPHATIC GLANDS OF THE THORAX.

§ 1645. The lymphatic glands of the thorax comprise the glands of the parietes of the thorax, those of the mediastina, and those of the lungs.

I. OF THE GLANDS OF THE PARIETES OF THE THORAX.

§ 1646. They are very small, and their number varies exceedingly. They are found in no determinate order, principally between the external and the internal intercostal muscles, particularly along the heads of the ribs, on the side of the vertebral column. Opposite these latter there are from six to ten on the anterior face, along the course of the internal mammary artery.

II. GLANDS OF THE MEDIASTINA.

§ 1647. The glands of the mediastina are distinguished into those of the anterior and those of the posterior mediastinum.

The glands of the posterior mediastinum, descend along the esophagus and the aorta, and communicate outwardly with the posterior glands of the parietes of the chest. They are numerous but small. The largest are those which correspond to the central dorsal'vertebræ. They not unfrequently swell and cause dysphagia, as Van Geuns has remarked.

Those of the anterior mediastinum are from eight to ten in number, and reascend along the anterior face of the pericardium from the diaphragm. They are rarety diseased, as Cruikshank has observed, and as we also have remarked.


III. BRONCHIAL GLANDS.


§ 1648. The bronchial glands (G. bronchiales, pulmonic œ, Vesalianœ) (1) are situated around the bronchi, but they penetrate, although gradually diminishing in size, in the substance of the lung along the ramifications of these channels. They are always numerous and large, and sometimes to an extraordinary degree. The largest usually exist

(1) Portal, Sur la struct are et sur les alterations des poumons, avec des remarques sur la nature de quelques symptômes de la phthisie; in the Mem. de Paris, 1760


382


DESCRIPTIVE ANATOMY.


before the bifurcation of the trachea between the two bronchi. In the adult they are more or less black. Sometimes this tint extends uniformly to every part; sometimes it exists in more or less broad and deep colored patches. In infancy, on the contrary, the bronchial glands are reddish, like those of all other parts of the body. We have observed, that before becoming entirely black, their surfaces are covered to a greater or less extent with black spots, which probably depends on the mode in which the lymphatic vessels are distributed. Generally they do not begin to be colored until the age of ten years, frequently not till twenty years. They do not all become dark at the same time, and their color gradually deepens.

The extent and the degree of coloring immediately relate not only to the age of the subject, but also to the state of the lungs, and perhaps even to the nature of the air which is breathed, particularly to the quantity of carbon it contains ; at least the bronchial glands are always proportionally larger and blacker in subjects affected with chronic disease of the lungs. They were even blacker than usual in a person affected with this disease, and who was in the habit of smoking.(l)

The black coloring matter is situated not only in the substance of the gland, but also in the fluids they contain, as it may be obtained by expression. The coloring substance seems to be pure carbon, (2) which Pearson thinks is not derived wholly from without.

Although these bodies are generally considered as true lymphatic glands, they are not admitted as such by all authors. Some, as Portal, distinguish the lymphatic glands of the lungs from the bronchial glands, or admit in the lung only a single species of glands, to which they refer the bronchial glands also ; but instead of regarding these bodies as lymphatic glands, consider them secretory organs. This is particularly the opinion of Senac.(3) This anatomist thinks, and in regard to the bronchial glands, Portal also, that they inclose a cavity communicating with the trachea by a canal, which may be easily demonstrated in a diseased state, by passing into it a bristle, and through which it is easy to cause the fluid they contain to pass into the trachea.

Not unfrequently, also, the most perfect similarity exists between the liquid contained in these glands, and that which lines the parietes of the trachea. Senac thinks that they do not act in the fetus : according to Portal, their action continues during life.

According to Portal, the bronchial glands differ from the lymphatic glands of the lungs admitted by this anatomist to exist independently of them, in their situation, volume, and form, since the lymphatic glands are not placed like them below the ramifications of the trachea, but are dispersed irregularly in the substance of the lung, and are collected

(1) Pearson, on the color ing matter of the black bronchial glands and on the black spots of the lungs ; in the Phil. Irans., 1825, plate ii. p. 166.

(2) Pearson, loc. cit., p. 164.

(3) Sona t, TV. du cœur, vol. ii. p. 686.


ADENOLOGY.


383


particularly on the surface of this organ ; they are also smaller, rounder harder, and evidently receive lymphatic vessels. They are also distinguished from them by their changes produced by disease, as the two kinds of pulmonary glands may be affected independent of each other.

We are, however, inclined to agree with those who make no distinction between the bronchial and the lymphatic glands of the lungs. All the characters assigned to them are purely accidental ; the bronchial glands even frequently differ from each other in all these characters, as one may judge from the details we have previously mentioned.

In examining bronchial glands which are very much swelled and which manifestly contain a liquid, we have never discovered any canal going from these bodies to the trachea ; and when these two organs communicate, it may depend on the enlargement or the morbid alteration of the glands, and their pressure upon the trachea ; and farther, some persons have expectorated ossified portions of these glands.

In fact, our observations have shown that the bronchial glands are more subject to ossification than all others, within the substance of the lung, or around the bronchi.

II. GLANDS OF THE ABDOMEN.

§ 1649. The abdominal glands occupy principally the cavity of the abdomen. We find but seldom one or more of small size in the paiietes of this cavity, for instance, above the umbilicus on the linea alba.(l)

The abdominal cavity of all the regions of the body, contains the most lymphatic glands, because there the form and functions of the lymphatic system are most completely developed.

They are principally situated in the folds of the peritoneum which unite the abdominal viscera with each other, and with the paiietes of the abdomen, and they may be divided into mesenteric, gastric , cœliac and lumbar.

I. MESENTERIC GLANDS.

§ 1650. The mesenteric are the largest and most numerous of all the abdominal lymphatic glands. (2)

They are divided into the proper mesenteric glands (Gr. mesenteric æ) and the mesocolic glands (Gr. mcsocolicœ.)

The proper mesenteric glands are situated principally on the left and convex side of the superior mesenteric artery. They are incomparably more numerous and larger than the mesocolic glands. We usually number more than one hundred of them, sometimes even more than

(1) Mascagni, lue. cit., p. 90.

(2) Werner and Feller ( Vasorum lacteorum atque lymphatieorum analomico-physiologica descriplio, Leipsic, tab. i), have figured some mesenteric glands and the lymphatic vessels of the small intestine. Barth, De glandularummesaraicaruminflammatione, Halle, 1820.


384


DESCRIPTIVE ANATOMY.


twice that number, differences which depend only partially on the length of the intestinal canal. Those which correspond to the jejunum are more completely developed in every respect, than those which receive the lymphatics of the ileon. They are rarely less than two inches from the intestine. From this point to the base of the mesentery, they gradually enlarge and approach each other, so that sometimes many are blended in one mass, resembling what is seen in many mammalia, where they are termed the panceas aselli.

These are principally the glands which are swelled in scrofulous patients.

The mcsocolic glands are much smaller and fewer than the preceding. There are seldom more than thirty ; sometimes there are only twenty ; in some rare cases there are fifty. They are situated nearer the intestine than the mesenteric glands, and sometimes rest directly upon it. There are still more in the transverse mesocolon, at the lower part of the ascending colon and in the sigmoid portion of the descending colon, than in the other regions.

These glands are rarely swelled even when the preceding are so.

II. G ASTRO-EPIPLOIC GLANDS.

§ 1651. The gaslro-epiploic glands ( G. stomacho-epiploce) are situated along the large ( G . ventriculi inferiores) and the small (G. ventriculi superiores) curves of the stomach. They are small and few, and not more than four or five to each curve.

III. CELIAC GLANDS.

§ 1652. Under the term celiac glands we may include, as Bichat does, the hepatic , the pancreatic , and the splenic glands. They surround a greater or less portion of the trunk of the vena porta, the splenic vessels, and the trunk of the celiac and superior mesenteric arteries.

IV. LUMBAR GLANDS.

§ 1653. The lumbar glands ( G. lumbar ts) are generally very numerous and very large, and surround, forward and on the two sides, the abdominal aorta and the ascending vena-cava, and also the renal vessels. The anterior are larger than the lateral, which are placed on the sides of the bodies of the vertebrae, and before their transverse processes.

IV. LYMPHATIC GLANDS OF THE LOWER EXTREMITIES.

§ 1654. The lymphatic glands of the lower extremities may be divided into the crural and pelvic.


ADENOLOGY.


385


1. CRURAL GLANDS.

§ 1655. Lymphatic glands are rarely found below the femoro-tibiai articulation. Cruikshank(l) and Hunter have never seen them. Sometimes, although very rarely, there exists on the anterior face of the leg, between the tibia and the fibula, a little below the middle of the limb(2) or higher, near the upper extremity of the interosseous membrane, a small gland, which we have once seen double ; this is called the anterior tibial gland (G. tibialis antica). The popliteal glands ( G. poplitece) are larger than the tibial, although they are very small. They are rarely more than three or four in number, and are situated deeply in the fat, and surround the popliteal vessels.

II. PELVIC GLANDS.

§ 1 656 . The pelvic glands ( G. pelvianæ ) are divided into the inguinal, the external iliac or hypogastric, and the sacral glands.

I. INGUINAL GLANDS.


§ 1657. The inguinal glands (G. inguinales ), are the largest in the body except the mesenteric. They are divided into superficial and deep.

The superficial vary in number from six to thirteen, and are situated directly under the skin, between it and the fascia-lata aponeurosis. They sometimes commence on the internal face of the middle of the thigh. The upper, which are constant, are always closer to each other than the lower ; they surround the upper part of the internal cutaneous vein of the thigh and extend to the symphysis pubis.

The deep are fewer in number, and vary from three to seven. They are placed below the crural aponeurosis, between the adductor, the sartorius, and the iliacus muscles, and surround the superficial crural arch.

The deep glands are not so constant as the superficial.

II. EXTERNAL ILIAC GLANDS.

§ 1658. The external iliac glands (G. iliacce. externat ) are six, eight, or ten in number, and extend along the external iliac vessels, from the crural arch to the beginning of the lumbar region, where they are continuous with the lumbar glands.

(1) Loc. cit., p. 117.

(2) Hewson, loc. cit., p. 27.

49


Vol. II.


386


DESCRIPTIVE ANATOMY,


III. HYPOGASTRIC GLANDS.

§ 1659. The hypogastric or internal iliac glands ( G . hypogastricÅ“, s. iliac ce internez ) also vary in number ; but generally they are more numerous than the external. These glands accompany the internal iliac vessels.

IV. SACRAL GLANDS.

§ 1660. The sacral glands (G. sacrales) are situated between the rectum and the sacrum. They are united laterally with the preceding and above with the mesocolic glands.

CHAPTER II.

LYMPHATIC VESSELS.

§ 1661, We may divide the lymphatic vessels of all parts of the body into superficial and deep. We shall describe them in the same order as we have the glands.


ARTICLE FIRST.

LYMPHATIC VESSELS UF THE HEAD AND THE NECK.

I. SUPERFICIAL LYMPHATIC VESSELS.

§ 1662. The superficial lymphatics of the head proceed under the skin. They are divided into those of the skull and those of the face.

The superficial lymphatics of the skull unite in from four to eight trunks, which form two fasciculi, an anterior and a posterior. The anterior descend along the temporal arteries, the posterior along the occipital artery. The first pass through some of the superficial zygomatic glands, the latter those which exist behind the ear. Both unite with the superficial lymphatics of the neck.

The superficial hjmphatics of the face are more numerous than those of the skull, because there is more of cellular tissue in the face. They descend along the vessels of the face, pass through, partly, the glands situated on the buccinator muscles, but principally and constantly across those which occupy the lower edge of the maxillary bone and the upper part of the neck.

In this place the superficial lymphatics of the skull and face anastomose frequently together, and with the deep lymphatic vessels of the head ; descend, in three or four trunks, some on the sides of the tra


ADENOLOGY.


387


chea, others on the posterior part of the neck, along the internal and the external jugular veins, receive the lymphatic vessels of the thyroid gland and of the muscles of the neck, and pass over the inferior lateral glands.


II. DEEP LYMPHATIC VESSELS.

§ 1663. The deep lymphatic vessels of the head are also divided into those of the skull and those of the face.

The deep lymphatics of the sfcull have not been pursued with clearness and certainty into the substance of the brain, but only into its membranes. They are seen here and there, especially when serum is effused upon the surface of the brain, both in the outer face of this organ, in the pia-mater and the arachnoid membrane, and likewise in the dura-mater, where they follow the course of the bloodvessels. Their trunks descend from the skull, along the internal carotid and vertebral arteries and the internal jugular vein, and unite with the superficial lymphatics of the skull and head, some in the superior, others in the inferior cervical glands. (§ 1662)

The deep lymphatics of the face , arise from the muscles of this region, from the nasal fossæ, and from the buccal cavity, penetrate into the superior cervical glands and unite, both within these glands and after emerging from them, with those which arise from the trachea and pharynx.

§ 1664. The trunks of all the superficial and the deep lymphatics of the head and neck, pass through the inferior cervical glands which they unite, anastomose very frequently with each other and with some vessels which come from the upper extremities and horn the cavity of the thorax, which arrive at the lowest of these glands, and unite in one or several trunks which open into the upper part of the thorac.ic canal, either directly into the angle of union of the jugular and subclavian veins, or finally into one of these last two, and then into the internal jugular, more frequently than into the subclavian vein.


ARTICLE SECOND.

LYMPHATIC VESSELS OF THE UPPER EXTREMITIES.

§ 1665. We must consider, at the same time with the lymphatic vessels of the upper extremities, particularly the superficial, the superficial lymphatics of the dorsal face of the trunk, and of the middle part of its anterior face : for all these vessels terminate in the axillary glands. This arrangement is demonstrated not only by dissection, but by the swelling of the axillary glands, when the vessels remote from these regions have been irritated ; as when, for instance, a blister has been applied to the epigastric region.


388


BESCH I PTÃŽ VE ANATOMY


I. SUPERFICIAL LYMPHATIC VESSELS.

I. SUPERFICIAL LYMPHATIC VESSELS OF THE DORSAL FACE OF THE TRUNK.

§ 1666. The superficial lymphatic vessels of all the dorsal face of the trunk, from the neck to the lumbar region, terminate in the axillary glands.

The superior, which arise from the neck, descend on the trapezius muscle, pierce the deltoides, and in this place, before arriving at the axillary glands, receive those which arise from the skin of the shoulder.

The middle and the inferior proceed transversely upward on the trapezius muscle, pass through this muscle, arrive outward, between it and the teres major muscles, and terminate in the axillary glands.

II. SUPERFICIAL LYMPHATIC VESSELS OF THE LATERAL AND ANTERIOR

FACES OF THE CENTRAL REGION OF THE TRUNK.

§ 1667. These vessels arise from the chest, and from that portion of the abdomen above the umbilicus.

The lateral , which extend lower than the others, penetrate through the obliquas externus abdominis, and the serratus magnus muscles.

The anterior and superior, the highest of which arise from the lower part of the neck, proceed on the pectoralis major muscle, turn on the lower edge of this muscle, and go backward to the axillary glands.

Some of these vessels, the deepest, pass through the rectus abdominis muscle in some subjects, into the internal lymphatic vessels of the thorax. Others, which are situated above, proceed through the deep muscles of the parietes of the thorax, and anastomose with the intercostal lymphatics.

These lymphatic vessels frequently communicate with the inferior, which descend from the anterior face of the abdomen to the inguinal glands.

III. SUPERFICIAL LYMPHATIC VESSELS OF THE UPPER EXTREMITIES.

§ 1668. The superficial lymphatic vessels of the upper extremities, are distinguished into external and internal.

The external commence on the dorsal face of the fingers, proceed first on their sides, follow the course of the cutaneous vessels on the back of the hand, and ramify in this place and in the fore-arm, on the external and posterior faces of which they principally ascend, and where they are farther increased by the lymphatic vessels which arise from this region. They proceed gradually forward and inward, so that near the humero-cubital articulation, the } 7 are situated entirely on the inner face of the limb.


A DENOI.OG V.


389


The internal arise from the internal face of the hand, also proceed along the lateral faces of the fingers, attended by the palmar vessels, anastomose in this place with the dorsal lymphatic vessels, and unite in the hollow of the hand hr three or four trunks, two of which are formed by the lymphatic vessels of the thumb and little finger, and a third and sometimes a fourth is formed by those of the other three fingers. They then ascend on the inner face of the fore-arm, and there receive several of the lymphatic vessels from the integuments of this region. All, or at least most of them, pass through the glands of the elbow, and unite at this point and higher with the external. The largest trunks which result from this union, and which are the fewest, ascend along the inner face of the arm, and following the course of the large blood-vessels, terminate principally in the axillary glands.

Some of them, but very few, attend the cephalic vein between the deltoides and pectoralis major muscles, and go to the inferior cervical glands.

II. DEEP LYMPHATIC VESSELS OF THE UPPER EXTREMITIES.

§ 1669. The deep lymphatics of the upper extremities accompany the deep vessels so exactly, that it is useless to describe them, and they may be known well enough by the terms radial, ulnar , and interosseous ( vasa l. radialia , ulnaria et interossea ). They proceed principally on the inside of the hand, the fore-arm, and the arm, frequently anastomose with the superficial, and receive at the upper part of the arm the small trunks which come from the pectoral muscles.

These deep lymphatic vessels partly penetrate into the glands which are rarely formed in the fore-arm, and all terminate in those of the axilla.

III. TERMINATION OF THE LYMPHATICS OF THE UPPER EXTREMITIES

AND TRUNK.

§ 1670. The lymphatic vessels hitherto described, and which pass through the axillary glands, unite in larger trunks within these glands and in the spaces between them, and are finally reduced to four or five in number, which surround the subclavian artery. They unite anew into two or three large trunks, in the place where this artery comes to the upper part of the chest ; these ascend behind the subclavius muscle, above the subclavian vein, and open directly into it, either alone or united with the deep lymphatics of the trunk, the head, and even also those of the left side, with those of the lower extremity.


390


DESCRIPTIVE ANATOMV.


ARTICLE THIRD.

DEEP LYMPHATIC VESSELS OF THE THORAX.

§ 1671. It is most convenient to describe the lymphatic vessels of the abdomen separately from those of the chest, and to place the history of the former after that of the lymphatic vessels of the lower extremities.

We distinguish the deep lymphatics of the chest into those of the parietes and those of the organs it contains.

I. LYMPHATICS OF THE PARIETES OF THE THORAX.

§ 1672. The deep lymphatics of the parietes of the thorax are divided into lateral, posterior , and anterior.

I. LATERAL AND POSTERIOR LYMPHATIC VESSELS.

§ 1673. The lateral and posterior lymphatics ( Vasa l. intercostalia poslericra ) arise from all the muscles which surround the chest and contribute to form its parietes, also from the pleura, and reunite with the posterior intercostal trunks, which proceed along the intercostal vessels. They also receive on the side of the vertebral column the lymphatic vessels which come from the muscles of the back and from the vertebral canal, pass through the lateral glands of the vertebral column, frequently anastomose and communicate, particularly the upper, with the glands of the lung, principally follow a more or less descending direction, and gradually terminate in the thoracic canal.


II. ANTERIOR LYMPHATIC VESSELS.

§ 1674. 'The anterior lymphatics of the parietes of the thorax, or the internal mammary lymphatic vessels ( Vasa l. thoracica profunda aniica, s. mammaria interna), arise by their deepest branches from the upper and anterior part of the abdominal muscles and the diaphragm, penetrate into the chest, below the xiphoid cartilage, proceed on both sides of the sternum and along its posterior face, pass through the glands in this place, and receive, on each side, the anterior intercostal lymphatic vessels ( Vasa l. intercostalia antica).

Those of the left side rarely reunite in two trunks, usually in one, which ascends obliquely before the left subclavian vein, passes through the inferior cervical glands, afterward descends on leaving this point, and opens into the thoracic canal, more rarely into the venous system.

Those of the right side commonly empty into the right subclavian and internal jugular veins ; but they also sometimes unite previously with the lymphatics of the head and of the upper extremities.


ADENOLOGY.


391


II. LYMPHATIC vessels of the thoracic viscera.

§ 1675. The lymphatic vessels of the thoracic viscera are divided into those of the lungs, the pericardium, the thymus gland, and the heart.

I. LYMPHATIC VESSELS OF THE LUNGS.

§ 1676. The superficial lymphatic vessels of the lungs arise on the surface of this organ from the pulmonary portion of the pleura, and form, on the lungs, a very complex network, with irregular meshes, which corresponds to the lobes of the viscus. Some of the trunks formed penetrate within the fissures of the lobes, and within the glands at the base of these spaces ; others proceed along the internal face of the lungs and empty into the bronchial glands.

The deep lymphatics of the lung arise from the substance of the viscus, anastomose very frequently with the superficial, proceed along the ramifications of the trachea and the pulmonary vessels, also enter into the bronchial glands, anastomose with the superficial vessels within them, and then proceed along the air-passages.

After leaving the bifurcation of the trachea, the lymphatic vessels which come from the bronchial glands, soon unite in three or four trunks, of which only one exists on the right and the others belong to the left side.

Both pass through some inconstant glands situated before and on the sides of the trachea, go behind the internal jugular vein on their side, and empty immediately, or in connection with the lymphatic vessels of the neck and upper extremities, into this or into the subclavian vein.

The pulmonary lymphatic vessels receive, on the trachea, those of the pericardium and of the thymus gland, which ascend into the anterior mediastinum after passing through some glands placed before the aorta and the vena-cava.

II. LYMPHATIC VESSELS OF THE HEART.

§ 1677. The lymphatic vessels of the heart principally accompany the large vessels of this organ, leave the pericardium and ascend on the aorta and the pulmonary artery, pass through the glands on the former of these two vessels, and unite, on one side, with the lymphatic vessels of the lung, the thymus gland, and the pericardium, and on the other, usually empty, by several small trunks, either into the thoracic canal or directly into the left jugular and left subclavian veins.


392


DESCRIPTIVE ANATOMY.


ARTICLE FOURTH.

LYMPHATICS OF THE LOWER EXTREMITIES, AND SUPERFICIAL

LYMPHATICS OF THE LOWER PORTION OF THE TRUNK AND

OF THE EXTERNAL GENITAL ORGANS.

§ 1678. The most proper mode of describing the lymphatic vessels of the lower extremities is to pursue the order adopted for the upper extremities and for the superficial vessels of the neck and back, and connect their description with that of the superficial lymphatics of the lower portion of the trunk and of the external genital organs.

I. LYMPHATIC VESSELS OF THE LOWER PORTION OF THE TRUNK.

§ 1679. The superficial lymphatic vessels of the lower portion of the trunk arise from the skin and the cellular substance of that portion of the abdomen below the umbilicus, the lumbar region, the haunches, and the perineum frequently anastomose with each other or with the superficial vessels of the lower extremities, communicate also, at least the former, with the superficial lymphatics of the upper part of the trunk, and empty into the inguinal glands.

II. SUPERIOR LYMPHATIC VESSELS OF THE EXTERNAL GENITAL ORGANS.

§ 1680. The superficial lymphatic vessels of the external genital organs arise in the male from the scrotum and penis, in the female from the labia pudenda and clitoris. Those of the penis and clitoris proceed, in two or three trunks, along the sides and back of these parts. They anastomose frequently with the superficial lymphatics of the thigh, and empty into the inguinal glands.

III. LYMPHATIC VESSELS OF THE LOWER EXTREMITIES.


I. SUPERFICIAL LYMPHATIC VESSELS;

§ 1681. The superficial lymphatic vessels of the lower extremities are situated between the fascia-lata and the skin, and are divided into anterior , which correspond to those of the anterior face of the fore-arm, and posterior , which are repetitions of those in the hollow of the hand and of the inner side of the fore-arm. The anterior arise from the back and sides of the toes, and from the back of the foot, ascend on the anterior and lateral faces of the leg, are finally placed on the inside of this limb, and then ascend along the internal face of the thigh.


ADENOLOGY


393


The posterior come from the sole of the foot, ascend along the posterior face of the leg, and anastomose frequently -with the anterior.

The largest and fewest trunks which are formed by the union of both, ascend along the internal and anterior part of the thigh, and empty at the summit into the superficial inguinal glands.

The superficial lymphatic vessels of the thigh, proceed principally along its internal and its anterior face. Even those which arise from its posterior face take the same direction. They anastomose with those of the leg, and go to the inguinal glands.

II. DEEP LYMPHATIC VESSELS.

§ 1682. The deep lymphatics of the lower extremities, are fewer than the preceding, and also differ in their situation, being placed below the aponeurosis.

They form four fasciculi, each of which unites in one or two small trunks, which proceed along the three arteries of the thigh and the external saphena vein. They arise from the same parts as those to which these arteries proceed, and from whence this vein arises, and all unite an the ham, in the popliteal glands.

The anterior tibial lymphatic vessels sometimes pass through the anterior tibial glands (§ 1655), which are not constant.

From three to six trunks come from the popliteal glands which are united by these vessels : these trunks ascend along the superficial popliteal and crural vessels which they surround, and receive principally the deep crural lymphatic vessels, which accompany the deep blood-vessels of the thigh.

These deep crural lymphatic vessels, which anastomose frequently with the superficial, enter, some into the deep, others into the superficial inguinal glands. Some pass before these glands, to the inferior iliac glands.

§ 1683. The superior deep lymphatic vessels which arise from the adductor and extensor muscles, and those which rotate the thigh outward, and also from those of the perineum, accompany the obturator, ischiatic, and gluteal vessels, and terminate in the hypogastric and sacral glands.


ARTICLE FIFTH.

ABDOMINAL LYMPHATIC VESSELS.

§ 1684. The abdominal lymphatic vessels divide like the thoracic, into those of the abdominal parietes, and those of the organs contained, in the cavity of the abdomen.


VOL II.


50


394


DESCRIPTIVE ANATOMY.


I. OF THE LYMPHATIC VESSELS OF THE ABDOMINAL PARIETES.

§ 1685. The lymphatic vessels of the abdominal parietes, are divided into the anterior , the lateral , the posterior, and the inferior.

The anterior arise from the skin, from the aponeurosis of the abdominal muscles and from the rectus muscle which they perforate, accompany the epigastric artery, and terminate in the external iliac glands.

The lateral come from the integuments, and from the lateral parts of the abdominal muscles, perforate the broad muscles in this region, proceed along the crest of the ilium, and arrive at the external iliac glands.

The posterior have their origin in the skin of the lumbar region, the quadratus lumborum muscle, the posterior part of the abdominal muscles, and the spinal canal, go inward with the lumbar arteries which they accompany, extend to the vertebral column, penetrate into its lateral glands, and anastomose frequently with those of the side opposite, on the anterior face of the vertebral column, thus giving rise to the lumbar plexus.

The inferior are distinguished into lateral and posterior. The lateral arise from the iliac bones, from the iliacus muscle, and from the levator ani muscle. They pass below the psoas magnus muscle, and go to the external and the internal iliac glands.

The posterior arise from the pyramidalis muscle, from the sciatic plexus, from the sacrum, and from the cavity of this bone. They terminate in the lumbar and the internal iliac glands.

All these lymphatics anastomose either at their origins, or within the glands which they enter.

II. LYMPHATIC VESSELS OF THE ABDOMINAL VISCERA.

§ 1686. The lymphatic vessels of the abdominal viscera, are distinguished into the deep lymphatic vessels of ihe genital and urinary organs, and into those of the digestive apparatus.

X. DEEP LYMPHATIC VESSELS OF THE GENITAL AND URINARY ORGANS.

§1687. The superficial lymphatic vessels of the genital organs, have already been described.

Among the deep, those of the penis and clitoris enter the pelvis along the deep blood vessels of those parts, go to the internal pelvic glands, and anastomose with the inferior lymphatic vessels of the parietes of the abdomen.

The lymphatics of the testicle, which are very numerous and proportionally very large, form two layers, of which the external arises from the tunica vaginalis, and the deep or internal from the substance of the gland. They unite in from eight to twelve trunks, ascend along


ADENOL0GY.


395


the spermatic cord to the inguinal ring, and go to the lumbar glands, following the course of the spermatic artery.

The lymphatics of the prostate gland and vesiculæ séminales, anastomose with those of the bladder.

The lymphatics of the vagina and lower part of the uterus, penetrate into the internal pelvic glands ; a part of those of the lower part of the vagina accompany the round ligament of the uterus, pass through the inguinal ring, and anastomose with those of the uterus. Those of the upper part of this latter organ which unite with those of the ovary, follow the course of the spermatic vessels, and terminate in the lumbar glands, like the corresponding vessels in the male.

§ 1688. Among the lymphatic vessels of the urinary passages, those of the bladder go to the internal pelvic glands.

Those of the ureters enter the external pelvic and lumbar glands, and anastomose with those of the bladder and kidneys.

Those of the kidneys arise from the outside and inside of these organs. The former, or the superficial , unite with the second or the deep , either directly or after forming several small trunks. The first is true of the internal, and the second of those which arise from the rest of the surface of the kidneys.

The trunks formed by the union of the deep lymphatic vessels, leave the renal fissure, accompany the renal vessels, anastomose frequently with those of the genital organs and of the capsulæ renales, and empty into the lumbar glands. Several of them open into the thoracic canal.

Those of the renal capsules unite, some with those of the kidneys, others with those of the liver, the spleen, and the intestinal canal.

IX. LYMPHATIC VESSELS OP THE DIGESTIVE ORGANS.

§ 1689. The lymphatic vessels of the digestive organs are divided into those of the intestinal canal, those of the stomach and the omenta, the liver, the spleen, and of the pancreas. They are also called the lacteal or chylifierous vessels , on account of the fluid they cany at the time of digestion. If however, we except at most the final branches, we ought not to distinguish between the lymphatic vessels which take up the chyle from the intestinal cavity and those which receive the lymph in the substance of the organ, since both fluids follow precisely the same direction.

I. LYMPHATIC VESSELS OP THE INTESTINAL CANAL.

§ 1690. The lymphatic vessels of the intestinal canal ( V. 1. intestinalia ), like the glands, are much more numerous in the small than in the large intestine : there are more also in the duodenum and the jejunum than in the ileon. They may be distinguished into superficial and deep.


396


DESCRIPTIVE ANATOMY.


The superficial arise from the peritoneum, between this membrane and the muscular tunic, and from the latter. They proceed along the intestine, and frequently anastomose together above and below.

The deep arise from the vascular and villous tunic, principally receive the radicles which absorb the chyle, follow a transverse direction, surround the intestinal canal like rings, and anastomose with the superficial, both on the intestine and between the folds of the mesentery. All unite in small trunks, which, two, three, or four in number, proceed between the folds of the mesentery, follow the course of the intestinal vessels, pass through the series of the mesenteric glands, gradually enlarge as they proceed, but become fewer in the same proportion, and anastomose near the pancreas with the lymphatic vessels of this organ, the spleen, and the liver, and concur with the latter to form one of the great roots of the thoracic canal . The lymphatic vessels of the descending colon however do not unite to produce the small trunks. They empty very low into the lumbar and sacral glands.


II. LYMPHATIC VESSELS OF THE STOMACH AND OF THE OMENTA.

§ 1691. The lymphatic vessels of the stomach and of the omenta, or the gaslro-epiploic ( Vasa l. gaslro-epiploica), also form a superficial and a deep layer. We may divide them, in respect to their course, into three fasciculi, which follow the course of the principal blood-vessels of the stomach.

Those of the left side, which arise from the base of the stomach, accompany the short vessels and go to the left, where they anastomose with those of the spleen.

The middle superior arise from the upper part of the rest of the surface of the stomach, go upward and to the left, pass through the glands of the small curvature of the stomach, and reunite at the left orifice of this viscus. Thence they go to the right, pass through the other glands, and anastomose under the liver with the inferior lymphatic vessels of this gland.

The middle inferior, which come from the rest of the surface of the stomach and from the large epiploon, proceed, in company with the blood vessels, along the large curvature of the stomach, pass through the glands in this place, go towards the right side, partially reunite with the middle superior, and go downward behind the pancreas to unite around the cceliac and superior mesenteric arteries, with the intestinal lymphatic vessels, with which they form one of the principal roots of the thoracic canal.

III. LYMPHATIC VESSELS OF THE SPLEEN AND THE PANCREAS.

§ 1692. Among the lymphatic vessels of the spleen and pancreas (F. /. splenico-pancrcatica), the superficial vessels of the spleen arise from its peritoneal coat, and the deep vessels from its substance. Tha


ADENOLOGY.


397


former are reflected around the edge of the spleen, and all, after reuniting in its fissure, leave this cavity, go to the right, accompany the splenic vessels, and anastomose there with the other lymphatics of the digestive organs.

Those of the pancreas soon join those of the spleen and the middle inferior lymphatics of the stomach.

IV. LYMPHATIC VESSELS OF THE LIVER.

§ 1693. The lymphatic vessels of the liver (V. I. hepatica ){\ ) are extremely numerous, and seem to differ from most of the others by the fewness and smallness of their valves. In fact we can generally succeed in injecting them from the trunks, and when injected their course is much more uniform than the others. They may be distinguished into superficial and deep.

a. Superficial lymphatic vessels.

§ 1694. The superficial lymphatic vessels of the liver (2) may in turn be divided into those of the upper and those of the lower face.

1. Lymphatic vessels of the upper face of the liver.

§ 1695. The superficial lymphatic vessels of the upper face of the liver form several fasciculi, which vary in number from four to ten.

Those of the middle fasciculus, which is the largest, arise from the middle region of the right lobe, partly also from the left lobe. They reunite in six or eight trunks, which enter into the suspensory ligament of the liver, and pass into the chest, between the diaphragm and the xyphoid cartilage of the sternum. There they reunite with the lymphatic vessels of the upper face of the diaphragm, form oné or two trunks, enter into the mediastinum, through which they pass from below upward, receiving several lymphatics from the pericardium, the thymus gland, and from the anterior wall of the thorax, and usually open into the left thoracic canal, just before it terminates. They frequently also empty partially or wholly into that of the right side. Sometimes several trunks of this fasciculus do not unite with the rest, but go to the left, pass into the coronary ligament of the liver, between the diaphragm and the left lobe, join the other fasciculi of the hepatic lymphatic vessels, and empty into the lower part of the thoracic canal, within the abdominal cavity or in the chest.

The second fasciculus arises from most of the surface of the right lobe, sometimes in a greater and sometimes a less extent. The trunks reach the right ligament of the liver, pass through the diaphragm in

(1) Schmiedel, De habitu naturuli venarum hjmpha.tica.rum in hepate , Erlangern

(2) Werner and Feller, De vasis hepatis superjicialibus, p. 34-44. — hoc. cit ., tables ii. iii. iv.


S 98


DESCRIPTIVE ANATOMY.


this place, proceed from below upward, and from behind forward on the convex face of this muscle, along its costal edge, and empty into the trunks of the first fasciculus. Others, which are smaller, go backward, and open into the lower part of the thoracic canal, anastomosing with the inferior diaphragmatic lymphatics.

The third fasciculus arises from most of the surface of the left lobe. Its trunks go to the left triangular ligament of the liver, separate in this place, unite with the upper lymphatic vessels of the stomach, and open into the lower part of the thoracic canal, which is still within the abdominal cavity.

2. Lymphatic vessels of the lower face of the liver.

§ 1696. The superficial lymphatic vessels of the lower face of the liver generally form fewer fasciculi than those of the upper face. Those too on the right side generally unite with those on the left. All anastomose with the superficial and the deep lymphatic vessels of the upper face, and give origin to small trunks. The latter approximate each other near the vena portæ, descend along the course of the hepatic bloodvessels, and reunite with those of the intestinal canal.

Other superficial lymphatic vessels of the liver enter into the substance of this gland but do not reunite to those described, and empty into the deep lymphatic vessels.

b. Deep lymphatic vessels.

§ 1697. The deep lymphatic vessels of the liver are much more numerous than the superficial, and accompany the hepatic blood-vessels and the biliary canals, emerge with the latter through the fissure of the vena portæ, and unite in the small epiploon, with the superior lymphatics of the stomach, emptying into the glands of this part, and reunite with the superficial lymphatics of the lower face of the liver, the lower lymphatic vessels of the stomach, those of the spleen and pancreas, descend along the hepatic vessels, anastomose at the base of the mesentery with the intestinal lymphatics, and form, in connection with them, one of the principal roots of the thoracic canal, the middle.


ARTICLE SIXTH.

OF THE THORACIC CANAL. (1)

§ 1698. All the lymphatic vessels open into the venous system of the body in two different places, at the union of the right and left inter (1) J. A. Leitersperger, Prœs. Salzmann, Encheiresis nova, qua ductus thoracicus una cum rcceptacula chyli in quovis subjecto humano demonstrari potest, Strasburg, 1711. — J, S. Henninger, De mesenterio, Strasburg, 1714. — C. P. Wium, De viis aTi

adenology.


399


liai jugular and subclavian veins. Most ol them empty into the left side ; this is the case with the lymphatic vessels of the left portions of the head and neck, those of the left upper extremity, the superficial vessels of the left portion of the trunk, all the deep lymphatic vessels of the chest, except those which arise from the right lung, those from the right portion of the heart and of the thyroid gland, generally also those of the right portion of the diaphragm, and of the right portion of the anterior wall of the chest, finally with those of the lower extremity and of the abdomen, except some which arise from the right half of the upper face of the liver.

On the contrary, the lymphatic vessels of the right portion of the head and neck, those of the right upper extremity, those of the right portion of the diaphragm, partially or wholly, and those of the right portion of the liver, go to the right side.

Those of the lower extremities, the intestinal canal, the stomach, and the spleen, most of those of the liver and the intercostal lymphatic vessels, do not empty directly into the venous system ; but they always open(l) one after another, into the left thoracic canal ( ductus thoracicus sinister), which is formed by their union. Those of the other organs, on the contrary, which we have described, do not empty except into the upper part of this canal, and in part also open directly into the internal jugular and subclavian veins.

I. LEFT THORACIC CANAL.

§ 1699. The lacteal vessels and the lymphatic vessels of the lower extremities, unite towards the first or the second lumbar vertebra, some mentorum et chyli., Copenhagen, 1717. — A. F. Walther, Obs. de ductu hepatico bipartite, vena bronchiali pinistra et inferiore, arteria hepalica, superioris mesaraicce sobole, Leipsic, 1731. — J. C. Bohl, De via lactea, Konigsburg, 1741. — C. M. Bussmann, Prces. Haller, De ductu thoracico, Gottingen 1741. — F. J. Narcissus, De generations et receptaculis chyli, Leyden, 1742. — C. H. Velse, De mutuo intestinorum ingressu et aliis machines humanæ extraordinariis, Leyden, 1742. — A. Portal, Sur la struct, du canal thoracique et sur celle du reservoir du chyle ; in the Mem. de Paris, 1770, p. 393402. — Sabatier, Remarques sur le canal thoracique de l'homme ; in the Mem. de Paris, 1780, p. 693.

(1) Lippi, demonstrator at the hospital, Santa-Maria-Nuova at Florence, seeking some unknown channel by which nature conducted the white fluids into the sanguineous system, without carrying them by a long rout to the thoracic canal, has found a large lymphatic trunk, which emptied into the ascending vena cava, at about the third lumbar vertebra, after passing from above downward, between the trunks of this vein, into which it opened in a direction opposite to that of the course of the blood. The orifice had a kind of valve. Some days after, the same anatomist remarked four distinct trunks which opened, one into the primitive iliac vein, and others into the vena cava. Having injected an inflamed liver, he saw some lymphatics of its triangular ligament, entering into the ramifications of the vena portæ. As he first injected the right side, Lippi undertook to do the same on the left. Having pushed the mercury into the external iliac lymphatics, whence this metal arrived at those situated behind the vertebral column, in the lumbar region, he saw several lymphatics on the left side, entering into the vena cava, some passing above, others below the aorta he also saw some emptying into the splenic and mesenteric veins : Lippi believed that he could distinguish the lacteals which open into the thoracic canal, from those of the external face of the peritoneum, which empty in great part into the veins with those which arise from the lower extremity. F. T.


40ö


DESCRIPTIVE ANATOMY.


times also between the second and the third, or even upon the twelfth dorsal vertebra, between the internal pillars of the diaphragm, and not below, to form the left or the proper thoracic canal. The chyliferous vessels frequently do not form a trunk, but open into this canal very near each other, and nine or ten in number. Most generally, however, the thoracic canal is formed by three trunks, a right, a central, and a left trunk. The first arises by the union of the lacteal vessels ; the other two are formed by the lymphatic vessels of the lower extremities. The right and the central are situated on the right side, and the left on the left side of the aorta. The first two unite before the third joins them. The latter sometimes unites to the principal trunk only by small branches.

§ 1700. The ancient anatomists admitted at the union of these vessels, and consequently at the commencement of the thoracic canal, a dilatation called the reservoir or cistern of Pecquet ( receptaculun , s. cy sterna chyli). This dilatation, however, is often very much contracted, and its apparent existence depends on the manner in which the lacteal vessels arrive at the thoracic canal. In fact they turn upon it, are enveloped by a common cellular sheath, and united by cellular tissue : when this sheath and this tissue are raised, the pretended reservoir almost always disappears.

In some subjects, however, the thoracic canal presents in this place a considerable dilatation, a kind of reservoir.

§ 1701. The thoracic canal passes into the chest behind the aorta, and on the right of it, between the internal pillars of the diaphragm. It is at first placed in the centre of the dorsal vertebrae, rather more to the right than to the left, between the aorta and the azygos vein, a little however before the latter, and directly behind the right layer of the posterior mediastinum. In ascending it goes to the left, but does not always preserve the same situation, although it is placed from the third to the sixth dorsal vertebra behind the esophagus, and is covered by this canal in a greater or less extent. After leaving the third dorsal vertebra, it ascends at the side of the esophagus, and passing behind the arch of the aorta, leaves the chest to extend to the upper edge of the last cervical vertebra. Thence it goes downward and forward, which much favors the progress of the chyle, and in most subjects, it empties itself at the angle of union of the left subclavian and internal jugular vein, usually by one trunk, rarely by several. It rarely opens into one of these two veins.

§ 1702. It is always a little narrower at the middle dorsal vertebra, but below this point again dilates more or less, as it receives the superior and pulmonary intercostal lymphatic vessels. It presents in its course no projections, but describes greater or less curves, and it does not receive many lymphatic vessels, except towards its upper extremity, where the trunks of the left half of the head and of the left upper extremity, open into it directly before it joins the venous system.

It is rarely or never perfectly single ; being always attended with a


ADENOLOGY.


401


greater or less number of accessory branches, which open with it, and immediately arise again from its parietes.

It very frequently divides, especially a little above the centre of the chest, into two, and sometimes into three branches, which almost always reunite after proceeding a greater or less distance. Sometimes it divides in this manner in more than one place ; the accessory vessels enlarge more or less, and assume the characters of real trunks. When this reticulated structure exists in the greatest degree, the whole of the thoracic canal is divided into two halves.(l)

§ 1703. The valves in this canal are not numerous, either near its origin, or near its termination. One pair exists above and opposite the upper dorsal vertebra. Higher up they are double or triple. The convex edge of these valves is turned downward, and their loose or concave edge upward. They are generally arranged in pairs, and rarely three and three, or singly.

We almost always observe, where the thoracic canal opens into the venous system, before its mouth, two very perfect valves, the loose edges of which are turned toward the cavity of the vein, and prevent the reflux of the blood into the canal. They are sometimes concealed by the valves of the internal jugular vein, so that some have pretended, but very unfortunately, that they were unconnected with the thoracic canal, because that they are farther from the heart than the orifice of the canal.(2)


II. RIGHT THORACIC CANAL.

§ 1704. The right thoracic canal, the formation of which we have already mentioned, is much smaller than the preceding (§ 1698), and is usually only an inch long. It descends to empty into the angle of union of the right internal jugular and subclavian veins, rarely into one of these two vessels. Sometimes it does not exist ; this occurs when the vessels which give origin to it open separately into the venous system.

§ 1705. There are always considerable anastomoses, not only between the vessels which unite to form the two common trunks, but also between these trunks.

The insertion of the large thoracic canal in the right half of the venous system(3) is undoubtedly only a greater development of these anastomoses, in accordance with the same law by which analogous phenomena are seen also in other parts of the vascular system ; for instance, the origin of the arteries of the fore-arm above the usual point, and that of the obturator artery by a trunk in common with the epigastric artery. This anomaly is indicated also by the division of the

(1) SÅ“mmerring 1 , loc. cit. p. 487.

(2) Portal, loc. cit., p. 393.

(3) Meckel, Ep. ad Hallerum, p. 30. — Cruikshank, in Ludwig, p. 152.


VOL. II.


51


402


DESCRIPTIVE ANATOMY.


thoracic canal into two halves, which we have already mentioned

(§ l 701 )- ,

When the great thoracic canal empties into the right side of the venous system, the lymphatics of the left half of the head, the neck, the arm, the lung, the heart, &c., do not join, but are arranged like the corresponding lymphatic vessels of the right side in the normal state.

Thus when we consider the gradual development of this anomaly, we see in it the first degree of lateral inversion.(l)

The insertion of the large thoracic canal, which takes place on the left side in the normal state, seems to depend on an effort to re-establish the symmetry which is deranged by the distribution of the venous trunks on the right side.

SECTION VIL

A COMPARISON OF THE DIFFERENT REGIONS OF THE VASCULAR

SYSTEM.

§ 1706. According to a law established in our introduction, there is an analogy but not a perfect resemblance between the different parts of the vascular system, in respect to its three dimensions, that is, from right to left, from above downward, and from before backward.

§ 1707. In accordance with the same law, the most marked analogy is that between the right and the left half of the system, which differ but slightly. Except inconstant variations, the only one of consequence is that in the arrangement of the trunks given off to the head and the upper extremities by the arch of the aorta (§ 1335). This difference seems to be only a part of a general type, which exists in all the arterial system. At least, the right superior aortic intercostal artery and the bronchial artery of the same side usually arise by a common trunk (§ 1439), even as in anomalies, several vessels of the right side often unite in a single trunk, while on the left side one trunk divides into several. Thus, for instance, the left carotid artery not unfrequently arises from the innominata, although the left vertebral artery often comes from the aorta : so too the left renal artery divides into several trunks more frequently than the right. In the single instance we have seen of the high division of the brachial artery on one side only, this was the left. This side also is the only one where we once observed an uncommonly high division of the popliteal artery. The obturator artery arises from the crural artery on the left side more frequently than on the right. When the innominata is divided at the arch of the aorta into its two trunks, the right subclavian artery rarely remains on the right : it goes to the left, and arises more on the left of the aorta ; so that in fact this anomaly seems to depend primitively on an extra

(I) See our Handbuch der path. Anatomie, vol. ii. part 1, p. 183.


COMPARISON OF T;IIE VASCULAR SYSTEM,


403


ordinary development of the left side and to the predominance of its type over that of the right side ; this opinion is strongly favored by the fact that in cases of this nature the right subclavian artery no longer takes the shortest course to arrive at its limb, but turns aside, passing behind the esophagus.

The special characters of the two extremities are often unusually developed simultaneously. Thus, for instance, the left carotid artery is a branch of the innominata, at the same time that the left vertebral artery arises directly from the aorta ; or the right and left carotid arteries are united in a single trunk, when the right subclavian artery arises below the left.

'The contrary seems to be the case with the venous and lymphatic systems ; for the left subclavian and common iliac veins are much longer than the synonymous trunks on the right side, and the superior and inferior thoracic canals of the left side unite, while the right superior proceeds alone.

Finally, the arrangement not unfrequently becomes unusually symmetrical, either by the union or the divisions of the trunks, or because a trunk which is generally placed on the right or the left proceeds on the median line.

§ 1708. Although the upper and the lower halves of the vascular system are less similar than the right and the left, the analogies between them much exceed their differences.

The diaphragm separates the upper from the lower half of the vascular system. If we compare these two halves with each other, after leaving this muscular septum, we obtain the following results :

1st. In the chest, as in the abdomen, the large circulatory system comprises two, which are smaller, viz. the pulmonary circulation in the thorax and that of the vena portæ in the abdomen. The trunk of the vena portæ is an imperfect repetition of the right half of the heart ; its arterial portion represents the pulmonary arteries, and the hepatic veins correspond to the pulmonary veins. The system of the vena portæ is a very imperfect imitation of the pulmonary system, because no muscular heart is there developed, and because the veins open into the general venous system. These are however two conditions, which alone or united occur- in the system of the pulmonary vessels of most animals which have blood-vessels, and which are below the class of birds.

2d. The upper and the lower halves of the arterial system are repetitions of each other in the following respects :

a. The superior and inferior diaphragmatic arteries correspond.

b. The esophageal arteries, the celiac, and the two mesenteric arteries correspond by large anastomoses.

c. The bronchial arteries are represented by a part of the renal and capsular arteries, and by the hepatic. In fact we may consider the liver, the renal capsules, and the kidneys, as analogous to the lungs, whence the vessels of these organs are repetitions of those of the lungs in different degrees of perfection. The vascular system of the liver resembles that of


404


DESCRIPTIVE ANATOMV.


the lungs, as it includes the different arteries of the system of the vena porta ; but it is less perfect. The renal and capsular vessels are still lower in the scale, for there we cannot trace the separation between the vessels of nutrition and those of secretion ; this separation is indicated in the kidneys by some vessels different from the renal arteries, which are distributed on the surface of these organs and in the renal capsules, by numerous vascular ramifications, which come from very different regions.

(/. The thymic arteries correspond to the spermatic arteries, as both generally arise from the trunk of the aorta, and the former frequently come from the bronchial arteries and the latter from the renal arteries.

e. The aortic intercostal arteries are represented by the lumbar arteries. In fact the latter are fewer ; but as the branches which arise from the middle sacral artery, a continuation of the trunk of the aorta, present the same arrangement as they, every difference in this respect disappears. The analogy remarked between the arteries which pass through the intervertebral foramina, above and below the diaphragm, is evidently strengthened by the fact that the superior intercostal artery is a branch of the subclavian (§ 1399), as the lateral sacral artery is one of the hypogastric artery.

f. The division of the upper and lower extremities of the aorta, and the arrangement of the vessels which arise from it on one side to go to the neck, the head, and the upper extremities, on the other to the organs of the pelvis and to the lower extremities, present a most striking analogy. The primitive iliac artery corresponds to the common trunk of the right subclavian and carotid arteries. It is true the analogy does not exist on the left side, but notwithstanding this difference is not essential, as it depends on a consecutive division, the analogy between the two regions is increased by the origin of the left vertebral artery directly from the arch of the aorta, between the left carotid and subclavian arteries, which is common, since this anomaly causes, in some measure, the union of the two vessels.

The carotid correspond to the hypogastric arteries, and the subclavian to the crural arteries, in respect to situation, origin, and distribution.

Of the trunks which arise from the carotid and the hypogastric arteries the superior thyroid and its branches correspond to the uterine and the vesical arteries, the facial and the ascending pharyngeal to the internal pudic and to its branches.

The differences in this respect are as follows :

The subclavian artery gives origin to the vertebral and the inferior thyroid artery ; the hypogastric to the gluteal and ischiatic artery. These latter are distributed like the branches of the subclavian and even of the axillary arteries. The former seem, at first view, to have none which correspond to them in the inferior vascular system, or to correspond to the vessels which arise from the hypogastric artery.


COMPARISON OF THE VASCULAR SYSTEM.


405


This difference almost disappears when the thing is examined attentively.

We cannot in fact deny that the vertebral and the inferior thyroid artery do not properly correspond to the hypogastric artery. The carotid arteries represent only a small part of the latter, which is much developed and reduced to a considerable trunk on account of the greater size of the parts it nourishes. The hypogastric artery is then divided in the upper part of the body into three trunks, the carotid, the vertebral, and the inferior thyroid artery. Hence why the inferior thyroid artery so often wholly or in great part arises from the carotid or the innominata artery, or is entirely deficient, or is replaced by the branches of the superior. The origin of most of the vessels of the neck and of the upper region of the shoulder from the inferior thyroid artery also favors this analogy very much, as these vessels are very similar to the gluteal, the ischiatic, and the obturator arteries.

The vertebral artery is ranked as a distinct trunk because of the size of the brain and the spinal marrow, organs to which it carries blood ; but it evidently corresponds in its mode of distribution, to the lateral sacral arteries furnished by the hypogastric artery.

Many vessels which correspond in their distribution, arise above from the subclavian, and below from the hypogastric artery.

The branches which arise directly from the subclavian and from the crural artery are very analogous. The internal mammary artery exactly resembles the epigastric artery, as the first proceeds on the sides of the posterior face of the sternum, and the second backward and on the sides of the linea alba which corresponds to this bone. The anterior intercostal arteries, given off by the internal mammary artery, are represented by the analogous branches of the epigastric artery.

The circumflex iliac artery seems to us to correspond exactly to the long external thoracic artery (§ 1405 ).

The external pudic arteries manifestly represent several external thoracic arteries.

In both extremities the trunk of the artery divides a short distance above the first articulation into a superficial vessel, which descends to the extremity of the limb, and into a deep vessel, which does not extend beyond the first articulation, that is, beyond the arm or the thigh.

The two circumflex arteries arise very high, sometimes from the superficial and sometimes from the deep trunk. They evidently correspond in their relations with the bone and the first articulation of the extremity, although they slightly differ in their distribution, as those of the arm are expanded in the superficial, and the femoral in the deep muscles, and also as one of the circumflex arteries of the arm is generally much smaller than its corresponding one in the thigh. This latter circumstance depends upon the greater development of the muscles of the thigh. The first depends upon the fact that the highest


406


DESCRIPTIVE ANATOMY.


branches, arising from the hypogastric artery, are distributed to the muscles corresponding to those of the arm, which receive the blood from the circumflex arteries.

The superficial brachial artery divides like the crural, at the second articulation, into two trunks, one of which soon bifurcates in a similar manner. The anterior tibial corresponds to the radial artery, the posterior to the ulnar, and the peroneal to the interosseous artery.

The division of these vessel's however differs remarkably, as it frequently occurs unusually high in the upper extremity, while this anomaly is very rare in the lower extremity, as is proved by our numerous observations and those of other anatomists.

It is difficult to assign the cause of this difference. The most probable explanation is that it depends upon the fact that the upper limbs form and are developed sooner than the lower, and are nearer the hear , Perhaps it depends partly on the greater length of the fingers, the volume of which, compared to that of the posterior part of the hand, much exceeds that of the toes, compared with the posterior part of the foot, and hence they always appear long before the latter. This anomaly, which is almost peculiar to the arteries of the upper extremities, would consequently arise from the normal arrangement of these latter ; to support which conjecture, we would mention the analogous difference in the arrangements of the muscles of the fingers and toes, since the hand presents no trace of the short flexor and extensor of these appendages of the foot. We even recognize with a little attention, that all the upper part of the vascular system differs thus from the lower ; for the separation of the carotid with the vertebral and inferior thyroid arteries, the constant separation of the carotid with the subclavian artery on the left side, the frequent origin of the vertebral artery with the latter, and the not unfrequent existence of a second inferior thyroid artery, (§ 1395 ) are analogous phenomena, of which we find no trace in the lower extremities.

Thus the vascular system of the upper part of the body is characterized by a tendency to divide. But it is not the only part where this tendency is remarked, since it is observed in the development of the brain, the multiplication of the organs of the senses, and the perfection of the extremities, which are perhaps the cause and condition of it.

The arteries of the lower extremities have entirely opposite characters. The circumflex arteries of the thigh are given off by the deep crural artery, more frequently than those of the arm are by the deep brachiaL The superficial crural artery seldom divides higher than usual, and the number of branches given off by the popliteal artery, is frequently less, because the peroneal or the anterior tibial, the first much more frequently and to a greater degree than the second, ceases to form a distinct trunk, and is replaced by the branches of the other vessels of the leg, precisely as the fibufa is in some measure only an appendage of the tibia, while in the fore-arm the radius and ulna are also developed, and both articulate with the humerus, and exactly also


COMPARISON OF THE VASCULAR SYSTEM.


407


as the toes are developed much more imperfectly, and much less movably than the fingers.

The articular arteries of the elbow and of the knee differ principally,

1st. Because the upper vessels of the thoracic extremity axise higher, and are always separated from the others, while those of the pelvic extremity are situated lower, and usually arise by a common trunk.

2d. Because the inferior arteries of the pectoral limbs aiise from the arteries of the fore-arm, and those of the abdominal members from the lower part of the popliteal artery. The internal and superior popliteal artery not unfrequently arises very high ; there are always two smaller inferior articular popliteal arteries which arise from the anterior and posterior tibial arteries, and not very unfrequently the recurrent radial artery is given off by tire brachial artei'y. When the popliteal artery divides a little higher than usual, its two branches furnish also the two largest inferior articular arteries of the knee.

Mairy anatomists mention as a difference in the distribution of the arteries of the hand and foot, the want of a superficial arch in the latter. We have never found this assertioxr to be connect, and it certainly depends upon a want of cai’e in searching into the analogies. In fact the internal plantar artery doubtless corresponds in its origin and course to the superficial palmar branch of the ulnar artery. Besides we have always known it to anastomose with the plantar branch of the anterior tibial artery, so as to form a superficial plantar arch.

But there is a real difference between the origin of the arteries of the fingers and toes, inasmuch as the former arise from the superficial, and the latter from the deep arch. This deviatioxr of the vessels on the surface of the sole of the foot, is sometimes developed to such an extent, that the arteries of the toes come from the superior rather than from the inferior perforating arteries (§ 1530). This arrangement appears to be intended to prevent the compression of the ai’teries of the toes by the weight of the body. Perhaps also it depends on the difference between the back and the palm of the hand, as also between the back and the sole of the foot, in regard to muscularity ; and perhaps the development, on the back of the foot, of the muscles which do not exist on that of the hand, is the reason that the arteries of the toes aiise more deeply. Finally, this difference sometimes disappears, since in some subjects the arteries of the fingers are given off by the superficial palmar arch.

3d. The veins of the upper and lower portion are perhaps more similar than the arteries, at least the arteries present a difference which does not exist in the arrangement of the left jugular and subclavian veins, and that of the left primitive iliac vein.

4th. The upper and lower portions of the lymphatic system, also present the same analogies in respect to the existence, the number, and the situ ation of the vessels and of the glands.

§ 1709. In the vascular system as in the rest of the organism, the analogy is not so great forward and backward, as from right to left.


408


DESCRIPTIVE ANATOMY.


and from above downward. We may, however, in this direction, compare the internal mammary and the epigastric arteries to the aorta, and its branches to the posterior intercostal and the lumbar arteries. So, too, there is a correspondence between the anterior and the posterior branches of the anterior and posterior intercostal arteries and of the lumbar arteries : perhaps in the neck and in the head, between the superficial and the deep arteries, certainly in these two regions, and in the spinal marrow, between the anterior and the posterior spinal, and also between the occipital and the frontal arteries; finally in the limbs between the anterior and posterior circumflex arteries of the humerus, the external and internal circumflex arteries of the femur, the superficial and the deep brachial and the crural arteries, the radial and the ulnar, and the anterior and the posterior tibial arteries, the dorsal arches of the back of the hand and of the foot, and the superior interosseous arteries of the plantar and palmar arches.

The venous system presents the same analogies, which are rendered still more striking by the existence of an azygos and of a semi-azygos vein, which correspond very evidently to the internal mammary veins.

We may compare with the large thoracic canal, which proceeds before the vertebral column, a second lymphatic duct, which ascends behind the sternum.


/


BOOK V.


NERVOUS SYSTEM.

§ 1710. The nervous system(l) is generally divided into that of animal life and that of vegetative life, or into the cerebral system and the ganglionic system. Both are composed of an internal or central part, and of an external ox peripheric. But we have already mentioned the reasons which prevent us from drawing the line between these two systems as distinctly as is usually established. We shall discuss the question more fully when speaking of the great sympathetic nerve. We shall then consider the nervous system as a whole, divided into a centre and a periphery.

SECTION I.

CENTRAL PART OF THE NERVOUS SYSTEM.

§ 1711. The central part of the nervous system is composed of the 3pinal marrow contained in the spinal canal, and of the encephalon contained in the skull. Bartels has proposed to designate it by the

(1) Besides tbe writers mentioned in the first volume who, in their general remarks on the nervous system, have given a complete description of the central part of this system, and who have even described in part its periphery, as Willis and Vieussens, we shall mention also the following, 1st, for the topography of the whole nervous system, A. Monro, An. of the human bones, nerves, and lacteal sac and duct, Edinburgh, 1732, 1750, 1777. — Id., Nervorum an. contracta lat. reddita a Coopmans , Franeker, 1754. — R. Martin, Institutiones neurologicœ sive de nervis corporis humani tractatio, Stockholm, 1781. — J. G. Haase, Cerebri ncrvorumque corporis humani anatome repeiita, Leipsic, 1781. — D. E. Gunther, Cerebri et nervorum distribulionis expositio , Duisburg, 1786. — G. Coopmans, Neurologia c. obs. de calcula ex urethra extracto, Franeker, 1795. — 2d. Topography of the whole central portion or of some of its parts; N. Steno, Discours sur Vanat. du cerveau, Paris, 1679. — H. Ridley, Anatom y of the brain, London, 1695. — V. Malacarne, Nuova esposizione delta vera struttura del cervcletto umano, Turin, 1776. — S. T. Scemmerring, Debasi encephali et originibus nervorum e cranio egredientium, Gottingen, 1788.— V. Malacarne, Encefalotomia nuova universale , Turin, 1780. — Scemmerring, Vom Hirn und Rückenmarck, Mayence, 1788. — Malacarne, Neuro-encefalotomia, Pavia, 1791, 1798. — Sœrnmerring, Tabula haseos encephali, Francfort, 1799. — Chaussier, Exposition sommaire de la struct et des diff. parities de V encephale, Paris, 1807. — Scemmerring, Acadcmicæ annotationes de cerebri administrationibus anatomicis vasorumque ejus habitu, in the Denkschriften der acad. zu München, 1809. — Rosenthal, Beytrag zur encephalotomie, Weimar, 1815. — C. L. Somme, Recherches sur V anatomie comparée du cerveau, Antwerp, 1824. — Rolando, Saggio sulla vera struttura del cervello, in the Dizionario periodico di medicina, Turin, 1822, &c. Ludwig, Scriptores neurolugici minores selecti, Leipsic, 1791, 1795. — In describing each part of the nervous system we shall mention the authors who have treated of them specially.

â– Vol. II. 52


410


DESCRIPTIVE ANATOMY,


collective term cerebrum ; but the term cerebro spinal axis is better. It bulges very much in its anterior or cephalic part, while, in its posterior or spinal, it terminates in a rounded, long, and thin cord. In a full-developed man it does not weigh quite four pounds apothecaries’ weight.


CHAPTER I.

SPINAL MARROW.

§ 1712. Of the central parts of the nervous system we ought to mention first the spinal marrow ( medulla spinalis , s. dorsalis, corda spinalis, Gordon, Cerebrum oblongaium, Collins, ( 1 ) Corps et extrémité inférieure du prolongement rachidien de V enctphale , Chaussier), because it is formed first in the animal series and in the fetus.

§ 1713. Anatomists are not agreed as to the. limits of the spinal marrow. Its lower extremity is well marked because the central portion of the nervous system there ceases ; but all authors do not agree in respect to its upper extremity. Some confine the term spinal marrow to that part of the nervous system within the vertebral column, so that, in their opinion, it terminates at the first cervical vertebra and at the origin of the first cervical nerve. Others, on the contrary, include also under this term the lowest part of the mass within the skull, the medulla oblongata. Some also add the annular protuberance, the cerebral peduncles, the thalami optici, and the corpora striata.

The last two methods seem to us incorrect, because the medulla oblongata differs much from the cord contained in the spinal manow, not only in its size but also in its structure and situation, the arrangement and the distribution of its nerves ; and because in all these respects it resembles the rest of the mass lodged in the skull. As to the second, the only arguments in its favor are, that the spinal marrow continues uninterruptedly with the medulla oblongata, and that the annular protuberance seems to establish the boundary between this and the rest of the mass in the skull. But these two circumstances prove nothing, because the anterior cords of the spinal marrow are also uninterruptedly continuous with the cerebrum across the annular protuberance, and the posterior are also continuous with the cerebellum, on the outside of this protuberance, so that if we did not regard more essential differences there would be no separation between the cerebellum and the spinal marow, as the asserters of the third opinion mentioned above maintain.

(1) Rolando, Ricerehe anatomiche sulla struttura del midolla spinale, Turin, 1824. Ollivier, Essai sur l'anatomie et les vices de con formation de la moelle epiniere chez l’homme, Paris, 1823. — Racchetti, Della struttura della midolla spinale, Milan, 1816.


OF THE NERVOUS SYSTEM

411


I. EXTERNAL FORM.

§ 1714. Generally considered, the spinal marrow is cylindrical ; it is however a little broader fiorn one side to another than from before backward, and thus in the first direction it appears slightly flattened. It may be divided into a cervical and a thoracic part, according to the regions of the vertebral column it occupies ; in its extent from one extremity to the other it has several prominences.

The first is seen at the upper part of the neck, where the cord becomes a little broader. Its breadth is seven lines in this place, while above it is a little less than six lines. Its thickness from before backward, far from increasing, often sensibly diminishes, and is not quite half an inch.

The upper or cervical prominence extends from the lower extremity of the cervical portion to the upper extremity of the thoracic portion, where it suddenly stops. Its length is a little more than three inches, and occupies the space between the second cervical and the first dorsal nerve. It is broadest near the fifth cervical nerve. The middle region of the thoracic portion of the spinal marrow again contracts. It is a little thinner than the cervical portion above the upper prominence.

The spinal marrow forms, near its lower extremity, a second prominence, called the inferior or the lumbar , which is never as large as the upper, and which extends from the first lumbar to the third sacral nerve. This projection is two inches long and five lines broad. It gradually becomes thinner and terminates in a blunt point. This blunt extremity is generally single, sometimes it is evidently bifurcated, and presents a superficial transverse fissure from whence a tubercle arises.

After leaving this point, which corresponds to the first lumbar vertebra, the nervous substance diminishes : and at the extremity of the vertebral canal, the spinal marrow appears only as a rounded filament, a little larger above than below, not quite one line thick in its whole extent, and is formed by the pia-mater. This filament which may be divided into several longitudinal fibres, descends between the origins of the nerves of the lower extremities, concealed by them, and extends to the lower extremity of the spinal canal, where it is attached to the duramater.

Hence it follows that the nervous substance of the spinal marrow, or the proper spinal marrow, by no means fills the whole vertebral canal, and occupies only about two thirds of it, the cervical and the thoracic portions being to the lower portion of the vertebral column as 2:1. The spinal marrow is also smaller than the vertebral canal in its othertwo dimensions.

Its anterior and posterior faces present a longitudinal groove as far as the medullary substance extends ; this corresponds to the median line, and is the anterior and the posterior median groove ( scissurce medulla spinalis mediana anterior et posterior ), which divides this part into two symmetrical halves, a right and a left These two


412


DESCRIPTIVE ANATOMY.


grooves are extremely narrow, and anatomists differ in respect to their existence and proportional depth.

Some, particularly Haller, assert that the posterior is never or seldom found; Chaussier says expressly that the anterior groove is at least deeper and broader than the posterior ; others, as Blasius, Petit, Vicq-d’Azyr, Gall, and Carus, say that the posterior is deeper than the anterior, which Vicq-d’Azyr and Carus think is the broader.

Others, Gordon for instance,(l) mention no difference between the two grooves. Bichat also expresses himself vaguely, for he only says that the two lateral halves are very distinct particularly anteriorly.

We have .always observed an anterior and a posterior groove, the latter generally very narrow, and rarely deeper than the other, although neither penetrates to the centre of the spinal marrow and to its gray substance. When the posterior seems deeper than the anterior, we have several times found that it was enlarged during dissection, so that adopting the opinion of several correct anatomists-, our predecessors, we believe the anterior groove to be larger in every direction than the posterior. The latter is much more perceptible in the prominences, particularly the lower, than in rhe rest of the spinal marrow.

Besides the median groove we observe also, on each side, but not exactly between the first two, and a little nearer the posterior than the anterior, a more superficial groove, which proceed obliquely inward and forward, and are called the lateral grooves ( fissura laterales). These two grooves proceed then to meet each other and the posterior, whence each lateral portion of the spinal marrow is also divided into two other halves, an anterior and a posterior, the former being much the larger. But these grooves are generally only simple depressions, or are at least more superficial than the preceding We cannot trace them the whole length of the spinal marrow, and they are seen only in the upper region of its thoracic portion. They separate on each side, the most posterior part of the circumference of the spinal cord from the rest of this circumference, not far from the posterior median groove. They not only converge inward and forward, but also downward, in the longitudinal direction of the spinal marrow, until they finally unite at the summit of its thoracic portion.

These lateral grooves are much more distinct in the early periods of life, than at a later period, when they frequently disappear and leave not the least trace.

We must distinguish them from the other two lateral grooves, the anterior and the -posterior ( sulci laterales anterior et posterior) which exist on each side, the whole length of the spinal marrow, and which are much broader than the preceding. These grooves receive the roots of the spinal nerves; thus they include numerous small depressions, situated after each other, from above downward, and into which the branches of the nerves penetrate.


(1) Mem. de Paris, 1781, p. 599.


ÃœF TME NERVOUS SYSTEM.


413


The posterior is larger than the anterior.(l) It seems to be a real fissure, more than a simple groove, since it penetrates internally as a very thin wrinkle, in the same direction as the lateral groove described above, and meets that of the corresponding side. This posterior groove not only receives the posterior roots of the spinal nerves, but also marks the limit between the anterior and the posterior medullary cords, into which each half of the spinal marrow is divided, and which slightly project upon the surface of the spinal cord, which is otherwise rounded.

II. STRUCTURE OF THE SPINAL MARROW.

§ 1715. We have already described (vol. 1) the intimate texture of the spinal marrow ; we then have only to state in what manner the gray and the white substances are united, and the arrangement of the large division of these substances.


I. SUBSTANCES OF THE SPINAL MARROW.

§ 1716. The spinal marrow is composed of a gray and of a white substance, the first of which is every where surrounded by the second, and forms a nucleus which this latter envelops on all parts, or at least in most of its circumference.

These two substances differ in form. The gray is composed of a cent’ al transverse portion, and of two lateral parts, which send a penniform prolongation forward and backward. Each prolongation is arched, concave outward, convex inward, much thicker and blunter before than behind, where, except in the lumbar projection, which is almost as thick at its posterior part as in the anterior, it terminates in a point which is particularly evident in some subjects. It terminates loosely at the circumference of the spinal marrow, although it is not covered by the white substance, while the latter envelops its anterior extremity.

These penniform prolongations very probably, have intimate relations with the origin of the spinal nerves ; for the posterior extends exactly in the groove whence the posterior series of their roots arise, and the anterior also goes towards the anterior groove.

The white substance is arranged in an opposite direction from the grey, is convex externally and internally, and the gray nucleus is lodged in it as in a cavity. It is much thicker on its sides than in its other parts. Its right and left portions are not united forward except by a thin layer, which, however, exists through all the spinal marrow, and separates the anterior groove from the gray nucleus. Vicqd’Azyr(2) asserts that they are not united at all posteriorly ; he thinks that the posterior groove penetrates to the gray nucleus ; but they in fact appear to us to be connected by rather a thick medullary

(1) Loc. cit., p. 177.

(2) 7/OC. cit., p. 600.


414


DESCRIPTIVE ANATOMY.


layer, the existence of which is proved by dissection and by the analog}' of the brain.

The proportional quantity of the gray substance is not the same in all parts of the spinal marrow. There is more of it, at the lower than at the upper part of the cord. In the full grown fetus the lower part of the spinal marrow is frequently formed entirely of this gray substance, while in the rest of it a very distinct line of demarkation is already drawn between this and the medullary substance. Not unfrequently the gray substance in the adult is brighter, and the white browner than usual, and thus the texture of the medulla oblongata is more uniform than that of the rest of the central mass.

II. ARRANGEMENT OF THE GREAT DIVISIONS OF THE SPINAL MARROW.

§ 1717. The spinal marrow is composed in all parts of two lateral halves, or of two cords, which are fitted to each other, separated by two median grooves in most of their thickness, but united in the centre by the tranverse portion of the nucleus (§ 1716), backward and forward by the transverse layers of the white substance (§ 1718).

Each of these two lateral cords is formed of two halves ; an anterior which is much the larger, the form of which is that of a figure of 8 inverted ( oo ), and a posterior, which is much smaller and prismatic. The latter passes a little beyond the anterior posteriorly ; its base looks outward, and its summit inward.

Those two portions are separated by the posterior prolongation of the gray nucleus, and by the posterior lateral groove. The posterior cords are not only thinner and narrower than the anterior; they are also a little shorter, but not by any means in the same proportion. The lower extremity of the spinal marrow is formed entirely by the anterior, so that, seen from the side, it appears much lower in this place than in the rest of its extent.

Farther, each posterior cord is likewise composed of two portions, an external, which is larger, and an internal smaller, which are separated by a superficial but very distinct groove. Although this arrangement is also observed in the adult, it is much more evident in the early periods of life, and in animals, during their whole existence.

Most anatomists admit that the spinal marrow is composed of two lateral halves. Asch,(l) Monro, (2) and SÅ“mmerring,(3) have described the two cords which form it more or less minutely, the anterior which is larger, and the posterior which is smaller. Chaussier(4) even admits three on each side : he places the anterior and the posterior be (1) De prima pare nervorum ; in Ludwig, vol. i. p. 238.

(2) Ueber das Nervensystem, p. 22.

(3) Nervenlehre, p. 59.

(4) Loc. cit., p. 148.


OF THE NERVOUS SYSTEM.


415


tween the two median grooves and the anterior and posterior lateral grooves and the middle cord between the latter.(l)

§ 1718. The large lateral cords of the spinal marrow, are fitted to each other in all their length, separated by the median grooves, but again united and blended in the centre. This central part may be termed the anterior and posterior medullary commissures , and the median or cortical commissure.

Gall thinks that the anterior and posterior medullary commissures differ, the first being composed only on the two sides of longitudinal fasciculi, placed side by side, while the second presents on both sides transverse slips, which exactly fit into each other. As yet we have not been able to satisfy ourselves of these two arrangements.

The posterior cords remain on the same side in all their extent. The anterior, on the contrary, intercross at the upper extremity of the spinal marrow, and those of the right side pass to the left, and those of the left side to the right, and all cross obliquely in this place. This decussation which is about five lines long, is indicated on the posterior face, where the anterior fissure does not exist in all its extent, and gives place to a broad but very superficial depression, to reappear immediately, and even deeper than before on the medulla oblongata. It becomes still more apparent on its anterior face, when we carefully separate the spinal marrow transversely in this place. The two cords do not intercross, but pass in a mass from one side to the other : they divide into from three to five fasciculi, which pass some above the others, like the fingers when the hands are clasped. The anterior cords however, do not wholly cross ; their anterior and their posterior parts only present this arrangement. We may easily be convinced of this by a transverse section of the spinal marrow in this place : it is then very manifest, that a white medullary band is detached on each side from the posterior extremity of the anterior cord, which goes forward and inward; and intercrosses with that of the side opposite, while the lateral parts continue their progress from below upward uninterruptedly. By this decussation, the anterior part of the gray nucleus of the spinal marrow, is divided into two lateral portions, each comprised between the internal face of the decussation, and the external lateral portion of the anterior medullary cord.

But we have never found that the anterior internal part of the anterior cords of the spinal marrow which produce the pyramidal bodies of the medulla oblongata, remains on the same side, and that the intercrossing was confined to the fasciculi which proceed from the posterior

(1) Gall {loc. cit., p. 115) and Chaussier (Joe. cit., p. 148) assert that Highmore mentions each half of the spinal marrow as composed of four cords, and consequently that the whole number of these last is eight. It would seem that Gall repeated the assertion after Chaussier, but we find nothing to justify it in the passage referred to by the Paris professor (Anat. b. iii. p. 1. chap, viii.) and Linden also quoted by Chaussier, says nothing like it. Although Chaussier rejects Highmore’s opinion, it is not however contemptible, since by uniting Chaussier’s description and our own, we arrive at the same conclusion.


41(3


DESCRIPTIVE ANATOMY.


part of this cord to the medulla oblongata. (1) If it was thus the decussation would not be visible externally : the anterior part would continue uninterruptedly to proceed externally along the same side of the bodj r , and would receive the fibres from the posterior part of the cord on the other side only very deeply, but this is never seen.

This decussation is so evident, that we can hardly conceive of its being doubted by several anatomists, as Sabatier, (2) Vicq-D’Azyr,(3) Chaussier,(4) and Gordon(5). Gordon states that he does not speak of the two or three bands by which the anterior groove of the spinal marrow is interrupted at the union of the cervical with the cranial portion, except on account of the absurd theories with which physiologists have often connected it. But this decussation has been demonstrated since the time of Mistichelli,(6) by Petit, (7) who was the first to demonstrate it exactly: by Santorini, (8) by Vicq-D’Azyr,(9) with less of precision and clearness, (10) finally, it has been well described by Gall and Cuvier. It has been partly figured by Petit, Santorini, and Gall.

All the objections against its existence are refuted by a positive fact, that the particulars previously described in the whole spinal marrow, are observed only in the place mentioned, and are there constant.

But the cords of the spinal marrow intercross in no other place, and although the contrary has sometimes been maintained, (10) all other arrangements of the spinal cord which resemble these decussations, are only intended to unite the commissures.

The structure indicated by dissection, is demonstrated by the difference between the phenomena which occur when the central portion of the nervous system is injured either above or below the place we have mentioned.

§ 1719. The substance of the spinal marrow of man is solid, not only when it is perfectly devoloped, but even sometime after birth, although several writers have admitted a cavity within it. We may conclude this from the difference in the opinions of authors in regard to the situation and the size of this cavity. Stephanus mentions its existence only as a general fact, without telling where it is situated. (1 1) Morgagni asserts that it is placed in the centre of the spinal marrow, especially its upper part, where he has frequently found small longitudinal cavities entirely covered with gray substance, and where once even he found

(1) Rosenthal, Beitrage zur Encephatotomie.

(2) Mêm. sur lamoelle del’epine et ses enveloppes ; in the Trait, d'anal., vol. iii. p. 452.

(3) Mém. de Paris, 1781, p. 598.

(4) Loc. cit., p. 143.

(5) Human anatomy , vol. i. p. 177.

(6) Dell ’ apoplcssia, Rome, 1709.

(7) Lettre d'un médecin, 1710, p. 11.

(8) Septemdecim tabul., p. 28-29, vol. ii.

(9) Loc. cit., p. 598.

(10) We instance Bartel’s opinion, who considers respiration as a motion dependent on the brain.

(11) De diss. part. corp. hum., b. iii. Paris, 1545, b. iii. c. xxxv. p. 341.


OP THE NERVOUS SYSTEM.


417


one which was very large, five fingers long.(l) Portal seems to have observed it in the same place : but once he found it comprised all the spinal marrow, and that it appeared to be covered with a very thin membrane : and another time it extended only to the fourth cervical vertebra. Gall, however, describes two canals existing all the length of the medulla, one on the right, the other on the left, which do not communicate with each other, or with the cerebral ventricles, but terminating in culs-de-sac, in the thalami optici, where they enlarge and produce a cavity the size of an almond, while the single and median cavity of the other writers is considered by them only as a prolongation of the fourth ventricle.

We have never found in man after birth, a median canal or two lateral canals. The circumstances under which they have been found by Gall and Portal, prove them to have been morbid. From Gall’s observations, it cannot be doubted that the canals he saw were produced ! by art, since he remarks that they could be demonstrated only by dividing the spinal marrow in such a manner that air might be introduced for six or eight lines. The smoothness and distinctness of the surfaces do not prove the real existence of the canals in question, for the first circumstance depends on the softness of the nervous substance, and the second on th ecentral prolongation of the pia-mater. We shall add one observation which we have always made, viz. that the ease with which these canals may be demonstrated, is in a direct ratio with the softness of the medulla oblongata ; and it is much more easy by continuing the inflation to make these communicate with the fourth ventricle, than to follow them into the thalami optici. We have succeeded, when the spinal marrow was soft, in pushing air into its whole length, without employing any cutting instrument, and without thinking that the existence of a normal cavity was proved by the space found in a soft and viscous mass, after having employed such a mode.

We discover only at the top of the spinal marrow, a rounded and extremely narrow canal, from six to nine lines long, terminating below by a cul-de-sac, and continuous above with the floor of the fourth ventricle.


III. WEIGHT OF THE SPINAL MARROW.

§ 1720. The absolute weight of the spinal marrrow, in the adult when deprived of its envelops, and entirely separated from its nerves, is more than an ounce. It is to the brain as 1 : 40.(2)

(1) Adv.anat., vi. anim. 14.

(2) Chaussier establishes a ratio more favorable to the spinal marrow, as he gives the proportion as 1 : 19-25, but this is evidently wrong-, doubtless because the origins of the nerves were not removed.


VOL. II.


53


418


DESCRIPTIVE AN ATOMY .


IV. CONSISTENCE OF THE SPINAL MARROW.

§ 1721 . It is generally thought that the spinal marrow is softer than the cerebrum. When, however, it is observed in the recent state, we remark, that although it is less consistent than some parts of the encephalon, particularly the annular protuberance, it is at least harder than the cerebrum and cerebellum. (1)

CHAPTER II.

ENCEPHALON.

§ 1722. The encephalon ( enccphalwn ), or that part of the central portion of the nervous system contained in the skull, has a rounded and oblong form. It is composed of two parts, which differ in size and arrangement ; an inferior which forms its base, and a superior which extends upwards and on the sides. These two parts are however directly continuous with each other, and with the spinal marrow.

The upper part very naturally divides into two portions, the cerebrum and the cerebellum , which differ in respect to situation size and structure. But it is more difficult to establish divisions in the lower part, since the different segments which form it, pass into each other by less evident shades. Hence, also, the difference which exists between authors in regard to the extent of the parts embraced by the same name.

Thus the term medulla oblongata has been used to designate a greater or less segment of the lower part of the encephalon : but some give this name to all the parts which form the lower region of this viscus, while others apply it only to some of them, and are not agreed in respect to the number of the parts which are thus collecti vely designated.

Many have limited the meaning of the word still more, and employ it only to designate the lower part of the nervous substance, which extends from the occipital foramen to the annular protuberance. Such is, for instance, the method of Haller, SÅ“mmcrring, Cuvier, Chaussier and Bichat. Some of these anatomists, however, particularly Scemmerring, Bichat, and Chaussier, have considered the medulla oblongata not as a particular portion of the central mass of the nervous system, but only as the upper extremity of the spinal marrow, as we have already remarked.

The middle region of the encephalon is situated in front of this part, and is considered by some writers, as Chaussier and Bichat, as a special segment of this mass, called the cerebral protuberance ( protuberantia cerebralis ) by Bichat, and the mesocephalum by Chaussier.

But these two authors do not give it the same limits, for Chaussier

(1) Chaussier, p. 116. — Gordon, p. 182.


OF THE NERVOUS SYSTEM,


419


states it to be composed only of the annular protuberance, the tubercula quadrigemina, and of the valvula cerebralis, while Bichat includes in it also under the term prolongations , those medullary fasciculi which extend from the annular protuberance forward to the cerebrum, and backward to the cerebellum. Others, as Gordon, consider the annular protuberance as belonging to the cerebellum.(l) Vicq-d’Azyr had already said with more justice, that it must be described separately, and that it belongs neither to the cerebrum nor to the cerebellum.


ARTICLE FIRST.

MEDULLA OBLONGATA.

§ 1723. The best mode, in our opinion, is to include under the term medulla oblongata , not only what Haller and his successors have so termed, but also the annular protuberance ; to insulate this part from the rest of the encephalon, and then to divide the remainder into two other portions, the cerebrum and the cerebellum. We also maintain this position, as the portion we include under this term still belongs in common to the cerebrum and cerebellum, while that which is found in front of it, belongs only to the cerebrum, and that which is behind it makes a part of the cerebellum. We also ground ourselves on the fact, that what Haller and others term the medulla oblongata, differs so much from the rest of the spinal marrow in respect to structure, that we must consider it separately(§ 1713).

The medulla oblongata , in our opinion, occupies all the length of the base of the skull, from the large occipital foramen, to the posterior edge of the sella-turcica. Its form is irregularly quadrilateral as it gradually enlarges from behind forward. It is continuous below with the upper extremity of the spinal marrow, anteriorly with the cerebrum, laterally and superiorly with the cerebellum. We must therefore consider it the point of union, or the focus of these three segments of the central portion of the nervous system.

The posterior and inferior part, the proper medulla oblongata of several writers, may perhaps be termed the rachidian bulb, as Chaussiez^) and Bartels(3) call it ; the anterior and upper will retain its usual name of annular protuberance.

I. RACHIDIAN BULB.

§ 1724. The rachidian bulb ( bulbus rachidicus, bidbus rachidicus superior , e. medulla oblongata, Haller, pars cephalica, s. extremum cephalicum , s. spinalis medullœ principium ) is the most posterior and the most

(1) Loc. tit., p. 112.

(2) Loc. cit., p. 120.

(3) Vom. Athmen, p. 108.


420


DESCRIPTIVE ANATOMY.


inferior part of the encephalon, the direct continuation of the spinal marrow. It extends from the first cervical vertebra to the centre of the body of the basilar bone, and exactly fills the posterior part of the upper and concave face of this body.

It has the form of an elongated triangle, and swells insensibly from behind forward, and from below upward. It generally does not exceed an inch in length, and its greatest breadth is about eight lines.

I. EXTERNAL FORM.

A. LOWER PACE.

§ 1725. The lower face of the rachidian bulb is slightly convex, and divided by a groove two or three lines deep, into two halves, a right and a left, which is continuous with the anterior groove of the medulla oblongata, from which, however, it is slightly separated by the decussation of the anterior cords. (§ 1718)

This inferior face presents two pairs of eminences, the pyramids and the olivary bodies.


a. Of the pyramids.

§ 1726. The pyramids (eminentiœ, s. corpora pyramidalia, s. corpora pyramidalia antic a . , s. eminentiœ oblongœ, Gordon, medianœ internes ) are visible with the intercrossing of the anterior cords of the spinal marrow (§ 1718), and are situated entirely inward, so that their internal faces touch. They occupy the whole length of the medulla oblongata. They are from about two and a half to three lines broad. They gradually become broader from below upward, and at the same time their upper projects more than their lower part. They terminate anteriorly by a contracted and rounded extremity, at the posterior edge of the annular protuberance, which projects downward and forward much beyond it. At the same time, they separate slightly from each other, so as to leave in the median line, between them and the posterior edge of the protuberance, a small liiangular hollow, into which the pia-mater penetrates. The anterior groove of the spinal marrow extends between the two pyramids, and becomes deeper at their upper part. Although these eminences terminate as such at the annular protuberance, they how T ever pass uninterruptedly through it, and go forward.

There is no decussation above the point we have already mentioned (§ 1718). The pyramids are also separated from each other by the anterior groove, in the rest of their length, always excepting the place directly below their upper extremity, where they are reunited by a small transverse medullary commissure, about a line and a half high. This reunion occurs at least frequently, just before they separate from each other, as if in this place their substance was pressed forward.


OP THE NERVOUS SYSTEM,


421


Prochaska asserts(l) that there is no gray substance within them : we have succeeded no better than Vicq-d’Azyr(2) in finding it.

In passing from below upward, they send off filaments which are entwined around the olivary bodies.(3)

b. Olivary bodies.

§ 1727. The olivary bodies , the olivary eminences , the lateral eminences ( olivÅ“, s. eminentiÅ“ olivares, Vieussens, s. laterales , Chaussier, s. ovales, SÅ“mmerring, Gordon), are situated on the outside of the pyramids. They go a little obliquely from below upward, and from behind forward, and form a rounded very elongated prominence, the largest diameter of which is from above downward. The prominence which disappears gradually above and below, passes from the lower face to the lateral face of the medulla oblongata, and is about seven lines long, two and a half broad, and one high. The olivary eminences do not extend so high as the pyramids : they cease about a line below the posterior edge of the annular protuberance.

The roots of the hypoglossal nerve arise from the groove between them and the pyramids.

These eminences are medullary externally, but the thin layer of white substance which covers them, is easily raised, and we then perceive a solid gray elongated nucleus, surrounded by an uneven and serrated edge, the centre of which is white, and the circumference of a deep gray. This nucleus is always loosely imbedded in medullary substance, and is called the corpus fimbriatum ( corpus olivœ fimbriatum, s. denticulatum , s. rhomboideum). When cut longitudinally, tranversely, or horizontally, we see very evidently that the gray border of the olivary bodies is interrupted inward, and consequently that the white substance which they inclose, is continuous on this side with the pyramids. This gray edge, on the contrary, unites below with the gray substance of the spinal marrow. From the place of decussation, and even by this decussation, the gray nucleus of the spinal marrow is divided anteriorly into two halves (§ 1718). The olivary bodies seem to be only a development of this arrangement. In fact, new medullary substance develops itself in the gray substance as the spinal marrow enlarges in this place, and is continuous internally with the pyramids. It perhaps would be more correct to say that the latter enlarges outwardly, and that it penetrates into the gray substance in the same manner as the two halves of the spinal marrow separate from each other on the two sides, before it enters the skull, and are enveloped by the gray substance.


(1) Destmct. ner i\, Vienna, 1779. — Gpp. min. vol.i. p. 373.

(2) Mem. de Paris, 1781, p.587.

(3) Santorini, Septemd, tab., p. 26 — 27.


422


DESCRIPTIVE ANATOMY


B. LATERAL FACES. .

§ 1728. Thetwo lateral faces of the medulla oblongata, are sloped and slightly convex outward. They are formed by a medullaiy projection situated outward and backward before the olivary bodies, which goes from below upward, and from within outward, and arrives at the cerebellum. This projection is called the lateral pyramid , the restiform body, the crus of the cerebellum, the posterior eminence, the peduncle of the spinal marrow ( eminentia pyramidalis lateralis, Tarin ; corpus, s. processus restiformis, Ridley ; crus cerebelli ad medullam oblongatam, eminentia posterior, Chaussier; pedunculvs medullÅ“ spinalis, Gordon). Those of the two sides unite at their inferior internal extremity. Each of them is a prolongation of the posterior cord of the spinal marrow at its side. Where they unite, they project slightly inward. They separate from each other from below upward, from behind forward, and from within outward.

A thin medullary layer about three lines long, and less than three broad, leaves the back part of the upper edge of the restiform body on each side; this goes inward. These two layers are separated by the pia-mater, which passes from the restiform body of one side, to that of the other, but they never unite in a state of perfect development. They may be termed the small bridges of the rhomboidal sinus(§ 1729), and may be considered as indicating the union of the two posterior cords. A second and larger, and particularly thicker medullary prolongation, arises from the anterior part of the restiform body, and is covered by the root of the pneumo-gastric and hyoglossal nerves, and is attached to the choroid plexus of the fourth ventricle.

C. UPPER FACE OR CALAMUS SCRIPTORIUS.

§ 1729. The lateral face is imperceptibly continuous with the upper face, by means of the restiform body. This upper face is very much grooved at its anterior and larger part, and these present a triangular depression, which terminates in a point, and is called the rhomboidal sinus, the sinus of the medulla oblongata, the ventricle of Jlrantius, the fossa of the fourth ventricle, the triangular fossa the calamus scriptorius, (sinus rhomboideus, sinus bulbi rachidici, veniricidus Jlrantii,foveola ventriculi quarti, Chaussier ; fossa triangularis, Gordon) . This depression extends more or less into the upper extremity of the spinal marrow, where it gradually contracts to a considerable degree.

On the superior face of the medulla oblongata, directly at the side of the median depression, we observe two medullary cords, which gradually enlarge from behind forward, and are only the upper face of the anterior cords of the spinal marrow, which traverse the spinal marrow from below upward. Between them and the restiform bodies is a broader layer of gray substance.


OF THE NERVOUS SYSTEM.


423


a. Medullary striae of the upper face.

§ 1730. Near the anterior extremity of the upper face, we constantly observe white striæ,(l) which go from within outward, usually project a little, and generally extend from the median depression to the outer part of the face, but which vary in respect to their existence, number, volume, progress, and direction.

1st. Existence. They are, in fact, very constant : but they are sometimes deficient on one or even on both sides. We have never seen a case of the latter, but the former we have met with twice, and always on the left side. Prochaska(2) and Wenzel(3) have seen both.

2d. Volume. They vary in respect to the three dimensions. Sometimes they are extremely narrow from above downward, almost capillary, and at the same time single. In other cases they form considerable striæ, which are more than two lines broad. Sometimes, also, they are very thin, and do not pass beyond the inferior face of the rhomboidal sinus, and do not penetrate into it. They not unfrequently form a rounded projection above this same face, and penetrate more or less into the medulla oblongata, so as to arrive at its lower face. Finally their length varies much. Generally, but not always, some or all of them extend outward to the auditory nerve, and usually go inward to the median groove : but sometimes also they proceed beyond this groove, and blend with those of the opposite side. Not unfrequently they do not extend to it. We have generally remarked, that when they are large and numerous, they usually unite in part or entirely, on the median line.

3d. Number. Then number varies sometimes ; it is independently of their size, and most generally is inversely as the latter, from one only to fourteen.

4th. JLri'angement. The strife of one side generally interlace differently together.(4) They are however sometimes entirely distinct.

5th. Direction. Their direction, most generally, is more or less transverse, although a little oblique from behind forward. Sometimes they proceed almost directly forward. All, or at least some of these striae, most generally extend to the auditory nerve, as we have already stated, and very evidently form the most internal part of its origin.

Very commonly also, the anterior which compose the smallest part of the mass, go obliquely farther forward and outward towards the trifacial nerve, although we cannot clearly demonstrate any connection between them and this nerve. The posterior are sometimes attached to the filaments of the root of the pneumogastric nerve.

They frequently vary in a most striking manner, in every respect, on both sides of the body in the same subject.

(1) Prochaska De struct, nerv., Vienna, 1779.— Wenzel, De penit. struct, cerebri , ch. xxiii.

(2) Doc. cit., p- 388.

(3) Loc.cit. p. 171.

(4) Wenzel, toe. cit.. p. 173— We have seen this several times.


424


DESCRIPTIVE ANATOMY.


These striae are very probably not only the roots' of the auditory nerve, but are connected, although less evidently, both with the trifacial and with the pneumogastric nerve, of which we shall speak more fully, when endeavoring to establish a fewer number of cerebral nerves than is generally admitted.

b. Gray bands of the upper face

§ 1731. Before the white striae, we see on the upper face of the medulla oblongata, other larger and slightly elevated striæ,( 1 ) which arise at some distance outside of the median line, so that their internal extremities are never blended. These striae extend from within outward, gradually swell, are convex forward, and pass over the anterior part of the posterior pyramids. They always unite with the auditory nerve at their external extremity, and are very constant : for of ninetyseven cases they were deficient in only two. (2) They are called the gray bands ( fasciolÅ“ cinerea). They are also generally much marked, and are similar on both sides: but sometimes, although very rarely, those of the two sides are dissimilar, or they are scarcely perceptible on either : this peculiarity depends neither on the age nor on the sex. They arise generally by one, and rarely by two roots, and are always single on each side. Their intimate connection with the auditory nerve, is proved by the fact that it disappears in deaf people.

II. TEXTURE.

§ 1732. The cords of the spinal marrow enlarge in the medulla oblongata, and divide there into fasciculi, more evidently than in the spinal marrow. At the same time, the posterior separate from below upward, and distinct bodies, the olivary bodies , are developed in the substance of the anterior, which are unconnected with the organization of the spinal marrow.

The anterior cords of the spinal marrow, divide evidently into at least two halves, an anterior which is smaller, and a posterior which is larger. Of these two halves, the anterior cross and form the pyramids (§ 1726), the posterior ascend behind the olivary bodies, enlarge and form the floor of the calamus scriptorius, and of the fourth ventricle. We also find another smaller fasciculus, which Gall asserts, is not constant, which Rosenthal has described more exactly, (3) and which our dissections have shown to be constant. This middle fasciculus, which touches the olivary bodies, surrounds them and passes through the annular protuberance to go forward into the tubercula quadrigenina.

(1) The merit of having 1 2 3 made profound researches on these striae belongs to Wenzel, but he neither discovered their existence nor constancy, nor their connection with the auditory nerve, since all these facts are already mentioned positively by Prochaska. (loc. cit. p. 387-391.)

(2) Wenzel, loc. cit. p. 184.

(3) Beytrœge, p. 24—27.


OF THE NERVOUS SYSTEM.


425


The division of the posterior cords of the spinal marrow into two fasciculi (§ 1717) is still more evidentin the restiform bodies, on account of their enlargement. The internal, which are smaller, swell at the lower extremity of the calamus scriptorius, but disappear in a point before the restiform bodies have terminated their course towards the cerebellum.


II. ANNULAR PROTUBERANCE.

I. EXTERNAL FORM.

§ 1733. The annular protuberance, called also the bridge of Varolius (nodus cerebri, pons Varolii, emineniia, s. protuberantia annularis, protuberantia encephalica, commissura cerebri ), is a considerable and somewhat regularly quadrilateral eminence, extending however rather more from right to left than from before backward ; it is observed on the lower face of the cerebrum, projects more than three lines above the lower face of the medulla oblongata and the cerebral peduncles, gradually becomes thicker on each side near its centre, and is separated from the medulla oblongata and the cerebral peduncles, by very distinct limits. Its greatest length is one inch, its greatest breadth is one inch and some lines, and its greatest height, at its anterior extremity, is nearly one inch. Its anterior and posterior edges are convex on the sides, and concave in the centre, the anterior more so than the posterior. A superficial, but very evident groove, extends all along its inferior face from before backward ; this is continuous with the serrated portion of the anterior and of the posterior edge. On the sides, the annular protuberance imperfectly divides internally into two halves, one of which is turned toward the tubercula quadrigemina, the other up towards the cerebellum, and both turn around the posterior crura of the cerebellum.


II. TEXTUBE.


§ 1734. The annular protuberance is formed externally of white fibres, transverse and convex forward, of which the central and the anterior particularly incline very much backward, towards the cerebellum. It is very firm, and the firmest part of the centre of the nervous system. On examining it internally, which must be doneby horizontal, transverse, longitudinal, and even by perpendicular incisions, a little oblique from within outward, and from behind forward, we remark that its texture is very complex.

Immediately below the external medullary layer, we discover a grayish substance. This substance is not pure : it alternates the whole length of the protuberance with transverse and very numerous bands of medullary substance, which are thin and convex inward, and are attached to the external.

VOL. II.


54


426


DESCRIPTIVE ANATOMY.


About two lines above the lower face of the protuberance, we observe on each side, almost in the centre of each lateral half, insulated longitudinal medullary fibres, which are directed from within outward, and from behind forward, and alternate with the transverse fibres. They are convex below, and concave above. They form a fasciculus, about four lines high, which contains in its centre only white substance, through which the cortical substance passes upward and downward.

This fasciculus is the direct continuation of the pyramids. It continues uninterruptedly forward with the lower face of the cerebral peduncles.

Next comes always from below upward, a very thick layer of gray substance, interrupted by perpendicular layers of medullary substance, situated some behind the others; then, on this layer is another which is thinner, of longitudinal medullary striae, convex above, concave below, which arise behind the upper fasciculus of the anterior medullary cords of the medulla oblongata, pass above the central gray layer, blend forward with the lower and thickest layer of medullary substance, and thus arrive upon the upper face of the cerebral peduncles.

Consequently the upper and lower fasciculi which result from the division of the anterior cords of the medulla oblongata, again unite at their anterior part, in the annular protuberance.

The number of the longitudinal striae, especially the inferior, diminishes much from without inward. They are separated from each other, upward and downward, by gray substance, and disappear entirely at about the centre of the annular protuberance.

The central part is formed of gray and of white substance ; it is much higher in this place, and only some longitudinal medullary striae pass above it.

Thus the anterior medullary cords not only increase in size and divide in their course across the annular protuberance, but they are still directed from within outward.

III. WEIGHT OF THE MEDULLA OBLONGATA.

§ 1735. The entire medulla oblongata generally weighs a little more than half an ounce. Its weight then is to that of the spinal marrow, as 1 : 2 ; to that of the cerebellum as 1 : 1 0 ; to that of the cerebrum as 1:74: finally to that of the whole central mass as 1 : 86.

The rachidian bulb weighs three drachms ; the annular protuberance one.


OF THE NERVOUS SYSTEM.


427


ARTICLE SECOND.

CEREBELLUM.

I. EXTERNAL FORM.

§ 1736. The cerebellum ( cerebellum , s. parencephalis){\) is situated below the posterior part of the posterior lobe of the cerebrum, from which it is separated by the tentorium, and occupies the inferior fossæ of the squamous portion of the occipital bone. We may divide it into the body and crura, and the body comprises the lateral parts, and a centre.

§ 1737. The body of the cerebellum has a rounded and oblong form. Its greatest breadth, which is from side to side, is about four inches. It is about two and a half inches from before backward in its broadest portion : it is two and a half inches from above downward in its centre, and only half an inch at its edges ; in approaching which, it gradually becomes thinner, so that it seems a little flattened in the latter direction. Considered generally, it is circumscribed by two slightly convex faces, an upper and a lower, and by four obtuse edges, distinguished into anterior, lateral, and posterior. The upper face is sloped like a roof, that is, it projects most at its central part, whence it descends almost flat to the edges, backward, outward, and forward, although a little less in the latter direction. The inferior face, on the contrary, is concave from before backward, at its centre, so that the anterior and the posterior parts of this groove form the greatest hollow.

The two faces are separated by a groove an inch deep in most of its extent, which corresponds to the posterior edge, and thence goes inward. This is called the large or the horizontal groove of the cerebellum ( sidcus cerebralis magnus, Vicq-d’Azyr ; sulcus magnus horizontalis, Reil). This groove divides the cerebellum into an upper and a lower half, besides the two lateral halves into which it is divided by the median longitudinal groove.

The anterior edge is the shortest, and is rendered very concave by a broad depression. The two lateral edges are straight, longer than the anterior, and oblique from before backward, and from within outward. They are continuous with the posterior, where the cerebellum is broader between their posterior extremities. The posterior edge is the longest, and is composed of two very convex lateral halves, which are separated by a median groove, about four lines deep and three broad. This groove is continuous with the median depression of the lower face. Thus the cerebellum is narrower in the centre than in the rest of its extent, and is divided by the anterior and posterior depressions of the edges, and by that of the lower face into two halves, called very im (1) Rolando, Osservazioni sul cerveletto, in the Memoria della reale academia, della scienza di Torino, vol. xxix. p. 163.


428


DESCRIPTIVE ANATOMY.


properly, the hemispheres ( hemisphœrœ cerebeUi). Each of these hemispheres has an irregularly quadrilateral form. The outer face of the cerebellum is not smooth. We observe in it numerous slight elevations, formed by the upper face of the layers (lamincc). These elevations are convex externally, concave internally, and go unevenly from before backward, being separated by grooves, into which the pia- mater descends. These layers are not single, but they frequently subdivide and interlace, and are adapted to each other very exactly, even externally. The depth of the grooves, and consequently the height of the layers, are not every where the same. In the place where the grooves are very deep and very long, and where also the adjacent layers are entirely separated from each other, the cerebellum is perfectly divided into several segments, which are called lobes ( lobi ).

The best mode of describing the form of the cerebellum, is to examine separately its lateral parts and its centre.

I. LATERAL PARTS.

§ 1738. The two faces of the cerebellum, the upper and the lower, are divided very constantly by deep grooves into several lobes, which are superior and inferior.

I. UPPER LOBES.

§ 1739. The two lobes of the upper half of the cerebellum, are the upper anterior and the upper posterior.

1st. The upper anterior or square lobe ( lobus anterior , superior , s. quadrangularis ) is irregularly quadrilateral, and narrower forward and outward than backward and inward. It is continuous with that of the opposite side by a central part which is not contracted, and is the highest point of the cerebellum. The two united lobes have a semicircular form. Their posterior edge is convex and sharp, and is turned backward with the posterior face, while the anterior, which is concave, and which forms at the same time the anterior edge of the cerebellum considered as a whole looks forward. The blunt extremity which forms the anterior half of the lateral edge of -the cerebellum, looks forward and outward.

This lobe is separated from the upper posterior by a very deep groove, the superior groove of the cerebellum (sulcus superior cerebeUi , Vicq-d’Azyr).

2d. The upper posterior or semilunar lobe , lobe semi-lunaire ( lobus superior posterior , s. semi-lunaris) , comes immediately next the preceding. It forms the posterior and external part of the upper half of each hemisphere. It is semilunar, thicker and broader forward than backward ; separated backward from the lower posterior by the large lateral groove, and forward from the upper anterior by the upper groove : it is attached inward to the synonymous lobe of the other


OF THE NERVOUS SYSTEM.


429


hemisphere by a thinner and more sloping part, formed of white substance, called the commissure of the upper posterior lobes. The considerable groove between the two upper posterior lobes, forms the commencement of the lower posterior median groove.

II. INFERIOR LOBES.


§ 1740. There are four inferior lobes.

1st. The posterior or inferior semilunar lobe ( posterior inferior, s. semi-lunaris), forms the posterior superior and external part of the lower half of each hemisphere. It is separated from the superior and anterior by the large groove, (§ 1737) and from the next by the inferior external groove ( sulcus inferior externus ), which is very deep. It is divided by two considerable but more superficial grooves, into three concentric portions -which follow one another from behind forward, and diminish in size in the same direction.

The two lateral halves are connected by a narrow and slanting commissure, with which the middle of these three lobes is directly continuous, while the anterior and the posterior only touch on its sides.

The most internal segment has been considered a special lobe, and termed the small or thhi lobe ;(1) but this distinction seems to us inconvenient, because we might just as well consider the middle and anterior segments as so many distinct lobes.

2d. The inferior anterior lobe , the cuneiform or internal inferior or digastric lobe ( anterior inferior, s. cuneiformis, s. biventer), is much smaller. It is composed of layers, which proceed almost directly from before backward. It is broader and thicker forward and outward than it is inward, where it at first contracts very much, and then terminates together with the third segment of the preceding lobe, in a very bulging central part.

3d. The third inferior lobe, the lobe of the medulla oblongata, the spinal lobe, the monticule ( lobus inferior internus , ionsilla , Malacarne ; s. lobulus medullæ oblongata, s. monticulus, Vicq-d’Azyr; lobus spinalis, Gordon), is smaller than the preceding, and is composed of layers which proceed directly from before backward, and is convex both out(ward and inward. Its anterior extremity rests in the restiform body of the spinal marrow. (§ 1728) Posteriorly it gives origin to the uvula, which is inserted between the two amygdalae.

4th. The fourth inferior lobe, the lobe of the pneumo gastric nerve ( flocctdus , s. lobus nervi pneumogastrici, Vicq-d’Azyr, lobus subpeduncularis, Gordon), arises a little above and before the preceding, from the posterior edge of the peduncle which goes from the cerebellum to the tubercula quadrigemina, directly where this peduncle unites with that which extends from the cerebellum to the medulla oblongata. It arises in this place from a thin pedicle, descends between the auditory


(1) Malecarne, and Reil, loc. cit., p. 13.


430


DESCRIPTIVE ANATOMY.


and pneumogastric nerves, and goes forward downward and outward. Almost all of its medullary nucleus is exposed forward and backward, fimbriated in its whole extent outward, and only in its lower part inward, and is covered both outward and inward with gray layers.

The direction of this segment of the cerebellum, is precisely the opposite of that of the others ; it is also the loosest.

The two lobes become, upward and inward, a broad semicircular medullary lajmr, which rises above on the nodule, and is loose posteriorly, called the posterior medulary vail ( velum medulläre posterius). This layer swells on its internal edge, into a thick mass of medullary substance, folded crosswise, and covered with cortical substance, which assists to form the posterior part of the fourth ventricle.

II. CENTRAL PORTION.

§ 1741. Although, strictly speaking, the central part of the cerebellum is no where separated from the two lateral parts, by a want of continuity in the substance ; it however differs a little from them in form.

The distinctive character of the formation of this central part is, that it is formed by transverse layers and plates, and that except in its middle posterior region, it presents a rounded form bulging from behind forward.

On its anterior face is the most superior part of the cerebrum. The anterior part of its lower face is also very much elevated, but the posterior is lower. Its lateral faces and its anterior part are situated in a large depression, the direction of which is from before backward, which separates the two hemispheres.

The middle region is usually termed the vermiform eminence (vermis cerebelli ), and it is divided into an upper and a lower part.

I. UPPER PART OF THE MIDDLE RFGION.

§ 1742. The upper part of the middle region extends from the middle of the posterior edge of the upper face, above the anterior edge to the tubercula quadrigemina.

It is composed of the upper or anterior vermiform process and the cerebral valve.

The upper vermiform process may also be divided into three portions:

1st. The commissure of the two upper posterior lobes.

2d. The larger upper part, or the monticule ( moniiculus cerebelli).

3d. The lower part which is much smaller, or the anterior vermiform process.

The commissure of the upper posterior lobes, is thin, narrow, and lower than the lobes it unites.

The monticule, which is the highest part of the cerebellum curves from behind forward, and from below upward, as high as the posterior edge of the tubercula quadrigemina. It is formed of five segments


OF THE NERVOUS SYSTEM.


431


placed one after another from behind forwards, they become thicker from before backward, but the third is separated from the others by the deepest transverse grooves. These segments extend from the monticule into all the thickness of the hemispheres ; but they gradually contract in approaching the anterior edge, so that the monticule, especially on account of the rounded prominence in its centre, is almost three times as long, as are the lateral edges of the upper face of the cerebellum.

The lower smaller part, or the proper anterior vermiform process , has a direction the inverse of that of the monticule, that is, it proceeds from above downward, and from before backward. It is reflected near its posterior extremity at an acute angle, and is continuous with the cerebral valve, on which it rests directly its entire length.

II. CEREBRAL VALVE.

§ 1743. The cerebral valve, the large valve of the brain ( valvula cerebri, valvula magna, velum medulläre, velum medulläre anticum , pars anterior veli medullaris ), arises from the posterior extremity of the anterior vermiform process, and is attached on the sides to the inner face of the prolongations sent by the cerebellum to the tubercula quadrigemina, and terminates by its anterior extremity in the depression between the posterior pair of the tubercula quadrigemina. It contracts from behind forward, becomes thin, and terminates in a convex edge.

Its lower face is smooth. The upper presents posteriorly in nearly all its extent, transverse grooves, which generally extend only to the lateral edges ; it is frequently, but not always, divided by a slight longitudinal groove into two equal lateral parts. Its anterior part is much less extensive than the other, and smooth ; it is formed in its- greater and posterior part, of gray substance. It is also formed anteriorly, at least on its lower face by this substance ; we however usually find at its anterior extremity, or directly behind it, on the median line, a white band from one to two lines broad, convex posteriorly and narrower on the sides : it is terminated forward by a small point, which is attached to the groove between the two posterior tubercula quadrigemina. This band generally gives rise to some filaments of the fourth cerebral nerve, but goes mostly only in the upper edge of the anterior peduncle of the cerebellum, and disappears on its outer face.

III. LOWER PART OF THE MIDDLE REGION.

§ 1744. The lower part of the middle region of the cerebellum, commonly called the inferior vermiform process, is a little lower posteriorly than the posterior part of the two lower posterior lobes which it unites, although it is not so low as the commissure of the upper posterior lobes situated above it. It is formed of two halves, separated by a superficial transverse groove, and situated one above the other. It presents a


432


DESCRIPTIVE ANATOMY,


slight prominence in its centre, and is separated by a slightly perceptible contraction from the hemispheres which it unites.

The central part or the pyramid ( pyramis , Malacarne) is next to this prominence, and is separated from it by a very deep fissure.

This central part projects in every direction much more than the posterior, and is attached, by much narrower and lower lateral parts, to the posterior half of the inferior external lobe, and to the inferior internal lobe.

Next to the pyramid, from which it is separated by a deep groove, comes a narrow part which is easily divided into several lobes situated one over another, and which generally is not perfectly symmetrical, being turned first to the right, and then to the left. This part also projects still more, in proportion to its breadth, and is continuous with the amygdalae by a narrow and deeply situated medullary band.

Finally, we next observe the anterior and smallest part, called the nodule ( nodulus , Malacarne), which is continuous on each side, with the posterior valve.

Thus, the central portion of the cerebellum, considered as a whole, is so curved, first from before backward, then from below upward, next fiom above downward and from behind forward, that the two extremities of the vermiform process, which proceed toward each other, almost touch, and are separated only by the narrow face of the summit of the fourth ventricle.

II. TEXTURE.

§ 1745. The gray substance surrounds all parts of the cerebellum, except its lower face which corresponds to the fourth ventricle ; this is covered with medullary substance. The latter is continuous in the three prolongations of the cerebellum, anteriorly with the tubercula quadrigemina, posteriorly with the medulla oblongata, below, and on the sides, with the annular protuberance, and extends within this organ in ramifications, the collection of which is termed the arbor vita ; of this we may be convinced by vertical incisions.

The medullary trunks follow a more or less curved direction, to near the circumference of the cerebellum, and give off, in this course, a greater or less number of branches, which arise from their convex edge.

A thin layer of yellow substance, covered by a thick layer of gray substance, exists on the surface of each medullary branch. This arrangement causes the lamellar structure of the cerebellum, since each layer incloses a layer of medullary substance, and each of the laminæ into which the principal layers divide always corresponds to a medullary branch.

The middle and lower part of the cerebellum presents this arrangement most distinctly. We find, in this place, seven medullary layers,


OF THE NERVOUS SYSTEM.


433


three anterior, three superior, and one posterior ; the upper of which are the longest, and ramify most simply.

All these layers become much larger from within outward, so that, with their covering of gray substance, they represent cones, the summits of which are turned inward, and the bases unite with the parietes of the fourth ventricle, and are separated from each other forward by deep grooves.

The medullary substance is proportionally much less in the central part, upon which circumstance alone depends its smallness ; but externally it accumulates in a direct ratio with the enlargement of the hemispheres of the cerebellum.

§ 1746. A vertical section demonstrates that the medullary nucleus is thickest below, in the centre of the cerebellum, before the summit of the fourth ventricle, opposite the second and third segments, consequently in its anterior half. From this point to the circumference it grows thinner as it ramifies ; but we constantly observe that the medullary layers of several lobes are much broader, toward the surface of the organ, than they are when thejr aiise from the central nucleus.

This arrangement is not observed in the fourth lobe, the uvula, the pyramid, the cerebral valve, and the anterior vermiform process ; but it is very perceptible in the other two segments. In the anterior lobes of the third segment the medullary layer, soon after leaving the nucleus, swells out considerably in passing through the lobes. The layer of the upper and the posterior lobes arises from a nucleus, almost as large as the central medullary nucleus, situated before the summit of the fourth ventricle. In the fourth segment we find a similar, but smaller, nucleus, more than six lines long, which is attached to the central nucleus by a thin filament.

§ 1747. In following this method, which is undoubtedly the' strictest, we arrive at a new division of the medullary layers of the centre, and of the hemispheres of the cerebellum, very similar to the division mentioned above, but different from it in some *espects.

The first of these seven layers belongs to the posterior part of the anterior valve. It is the smallest, and the folds of the posterior part of the valve rest upon it.

The second is formed by the anterior vermiform process, and the anterior part of the upper anterior lobe.

The third is much larger, and belongs to the anterior part of the monticule, and to the larger middle part of the upper anterior lobe.

The fourth, the most posterior, corresponds to the most posterior part of the monticule, to the commissure of the upper posterior lobes, to that of the lower posterior lobes, to the most posterior part of the upper anterior lobe, to the upper posterior lobe, and to the upper part of the lower posterior lobe.

The fifth is composed of the pyramid, of the lower smaller part of the lower posterior lobe, and of the digastric lobe.

Vol. II. 55


434


DESCRIPTIVE ANATOMY.


The sixth corresponds to the uvula and to the amygdalæ. Finally,

The seventh, forms the nodules and fourth lobe ; it is the smallest of all, except the first.

The last two are distinguished from the rest, as they are not cleft and covered with a gray substance, except in one part of their circumference, forward and backward. The first presents this arrangement in every part, and the latter at its upper posterior part. The others are divided several times on each side ; they however present traces|of the arrangement above mentioned, because the lower anterior half of the segments, which are turned the most forward, and the lower posterior half, which are turned backward, present the most simple and shortest grooves and ramifications, the former downwardand backward, the latter downward and forward.

CORPUS FIMERIATUM,

§ 1748. In the centre of the medullary substance in each hemisphere of the cerebellum, little more internally than externally, we find a rounded, oblong, very vascular body, medullary internally, surrounded with a serrated edge, and intimately united to the medullary substance, called the rhomboid or fimbriated body ( corpus rhomboideum , s.fimbriatum , s. dentatum). Its gray edge mostly surrounds it, except its lower anterior part, where the medullary substance within it is continuous with that of the walls of the fourth ventricle, so that the hemispheres of the cerebellum are consequently composed of a double layer of medullary substance, and of gray substance ; the internal, formed by the corpus fimbriatum, and the external, comprising most of the external medullary substance and the external gray substance.

We here then find the repetition of what is observed in the medulla oblongata, in the olivary bodies, and the pyramids; (§ 1726-1727) only this form exists here in a greater degree, since the rhomboid body of the cerebellum is not only surrounded with a thin and smooth layer of white substance, as is seen in the medulla oblongata, but this layer is much thicker there, and not only forms several successive ramifications, but is covered a second time with grey substance.

§ 1749. The medullary substance of the cerebellum is extended in three fasciculi, which, however, are not distinctly separated ; they are called the prolongations of the cerebellum ( crura cerebelli). One is inferior and descending, another middle and anterior, the last is superior and ascending.

The inferior descending prolongation ( crus cerebelli descendons , s. ad medullam oblongatam) blends with the posterior cord of the spinal marrow or the restiform body. The superior ascending ( crus cerebelli adscendens, s. ad eminentiam quadragesimam ) goes to the posterior tubercula quadrigemina. The middle lateral or anterior ( crus cerebelli ad porlum) goes forward and downward, and blends with the annular protuberance. Of these three prolongations, the third is the largest. The first two are situated farther inward, and surrounded by it, so that


OF THE NERVOUS SYSTEM.


435


the rhomboid body exists between it and them. They blend forward and backward, and seem developed principally to form the middle region of the cerebellum, while the hemispheres of this organ rest on the lateral prolongations, so that the medullary layers which form them, are directed* forward in the upper lobes, and backward in the inferior.

When we separate longitudinally a cerebellum hardened by immersion in alcohol, it is divided into an upper and lower half ; we also see on one side a very broad but thin transverse medullary layer, which contracts and at the same time becomes thicker from before, backward and outward, and which is expanded to form the lateral prolongations : we have on the other side, particularly towards the centre, fasciculi which intercross from before backward, so that the ascending and descending prolongations, at least to some extent, are not directly blended with each other, but reciprocally interlace.

§ 1750. The cerebellum forms most of a ring, which is constituted below by the lower part of the annular protuberance, embraces the cerebral peduncles, and unites by its anterior and posterior prolongations, with the medulla oblongata, and with the cerebrum.

III. WEIGHT.

§ 1751. The cerebellum, if separated at the place where its prolongations enter the annular protuberance, the cerebrum and the medulla oblongata, generally weighs five ounces. Its weight consequently, is to that of the rest of the encephalon, as 1:8, or as 1 : 7, rarely as 1 : 10, or even as 1 : 11.(1) In the latter case, we must attribute its excess of weight to the suspended development of the encephalon.

IV. CONSISTENCE.

§ 1752. The cerebellum has about the same consistence of the cerebrum, and like this, it is softer than the medulla oblongata, and harder than the spinal marrow.

ARTICLE THIRD.

CEREBRUM.

I. EXTERNAL FORM.

§ 1753. The cerebrum forms most of the cephalic portion of the centre of the nervous system, and occupies its upper and anterior region.

Considered as a whole, its form is a rounded oblong, and it is for the most part convex. Its length exceeds its breadth, and particularly its height. Its greatest length is six inches, its greatest breadth is five, and its height is four. It is broadest and highest in its centre.

It is formed of two lateral and perfectly similar halves, called hemis

(1) Chaussier, loc. cit., p. 77.


436


DESCRIPTIVE ANATOMY.


pheres or lobes (hemisphere,, lobi, Chaussier). These two halves are separated at their upper part by a longitudinal fissure ( fissura Icngitudinalis), much broader backward than forward ; in the former direction its breadth is half an inch, but hardly a line in tire latter. They are on the contrary, almost blended with each other at their middle and lower portion.

Each hemisphere is divided into two lobes (lobi, lobuli, Chaussier), an anterior and a posterior. The anterior is more than twice as large as the posterior. They are separated by a groove more than an inch deep, the direction of which is oblique from above downward, and from behind forward ; this is called the groove of Sylvius ( fossa Sylvii), Red terms it the valley. This separation exists only below and on the side, for the groove does not extend to the upper face.

The posterior lobe is also frequently divided into two others, termed the middle and posterior lobe. The latter forms that part of the cerebrum which rests on the tentorium. It cannot be distinguished externally from the middle lobe, but is separated from it on its internal face by a fissure, the direction of which is obliquely from above downward, and from behind forward, and on the lower face by a slight depression.

In each hemisphere we distinguish an inferior, an external, a superior and an internal face.

I. INFERIOR FACE.

§ 1754. The inferior face should be examined first, for we there recognize most distinctly, that the cerebrum is directly continuous with the medulla oblongata.

Of the three faces, this is the most irregular, and its central portion is entirely separated from the two lateral parts.

I. MIDDLE REGION.

I. CEREBRAL PEDUNCLES.

§ 1755. We first observe from behind forward, directly before the anterior edge of the annular protuberance, (§ 1733) the cerebral peduncles, or the crura of Ike medulla oblongata (crura cerebri magna, crura ad medullam oblongatam). They are two large rounded bodies, about eight lines long, which become much larger from before backward, seven lines broad posteriorly, ten anteriorly, ten lines high, grooved longitudinally, and entirely formed of substance, white externally. They diverge from each other behind forward, and are separated at their lower part by a very broad and deep groove; this is only the anterior groove of the spinal marrow, which is deepened by the development of the peduncles. This part forms above the floor of the aqueduct of Sylvius ; its lower face is gray, and numerous vessels pass through it, the direction of which is from below upward, and from without inward. Vicq-d’Azyr(l) terms it the middle perforated substance (substantia perforata media).


(1) Lac. cit., p. 545.


OF THE NERVOUS SYSTEM.


437


Near the posterior extremity of these bodies there is generally a transverse and slightly projecting band which passes over all their lower face, and crosses the longitudinal groove. A second posterior transverse band is detached from where the anterior and middle prolongations of the cerebellum unite, and is directed from behind forward, and from above downward between the two peduncles, proceeding on their lower face. This band is situated directly before the annular protuberance, and is often united with it, representing to a certain extent a distinct edge. The cerebral peduncles are covered posteriorly by the anterior part of the annular protuberance, forward by the root of the optic nerve, which turns on them from above downward, from without inward, -and from behind forward.

§ 175G. The cerebral peduncles are formed externally by a layer of white substance about two lines thick. Next comes a rounded and elongated layer of blackish substance, which has a semicircular form, as has the whole cerebral peduncle, being concave above and convex below. Next comes a third layer, the thickest ; this extends upward to the surface, and is formed of a mixture of gray and of white substance.

§ 1757. Between the anterior extremities of the two cerebral peduncles, is a broad triangular surface, which enlarges very much from behind forward, and is continuous posteriorly with the middle portion, anteriorly with the anterior part of the perforated substance of the lower face. The direction of this surface is from behind forward, and from above downward at its posterior part, from below upward, and from behind forward at its anterior part, which is more perpendicular than the other ; it forms the floor of the third ventricle. We remark from behind forward the mammillary eminences, the infundibulum with the pituitary gland, the anterior part of the root, and the decussation of the optic nerve ; the rest of it is formed of gray substance.

II. MAMMILLARY EMINENCES.

§ 1758. The mammillary eminences or pisiform tubercles , ( eminentiÅ“ medulläres , s. candicantes , s. mammillares , Chaussier) are situated side by side between the anterior extremities of the cerebral peduncles ; they are two hemispherical prominences, formed externally of medullary substance, and internally of cortical substance, about half a line distant from each other in their whole height, but separated a littlefarther posteriorly. They are the inferior and anterior extremities of the fornix.

When attentively examined, we observe that these triangular eminences are each composed of a larger inner, and a much smaller outer half. The anterior and inner faces are straight, the posterior is convex ; the latter is the longest, the inner is much the shortest. The two halves of each eminence are very distinctly separated ; the internal projects very much ; the outer terminates in a point on the outside of the gray substance, between the mammillary eminence and the optic nerve.


438


DESCRIPTIVE ANATOMY.


III. INFUNDIBULUM AND rlTUlTARY GLAND.

§ 1759. We find a rounded and conical prolongation between the mammillary eminences, called the infundibulum ;( 1) this descends obliquely forward, and terminates in the pituitary gland or body ( hypophysis cerebri , s. glandida pituitaria, Chaussier).(2) This is situated in the sella-turcica of the sphenoid hone below the dura-mater, which covers its upper face, and is closely surrounded on all sides. The lower extremity of the infundibulum, is connected with it by a narrow opening in the dura-mater. The lower and the upper parts of the infundibulum are thicker than its centre. In its first two parts it is about a line thick. It is formed of gray substance.

The pituitary gland has an oblong rounded form. It is about six lines broad, three long, and less than three high ; it generally weighs, including the infundibulum, eight grains. It is always formed of an anterior and a posterior lobe, which are intimately united. The anterior is very large, and generally twice the size of the other.

The anterior is bean-shaped ; the posterior is more rounded, and is situated in the posterior and serrated edge of the anterior lobe.

The pituitary body is generally very hard, but its posterior lobe is softer than the anterior.

The anterior lobe is formed of two substances, an external reddish, and an internal which is white, which vary much in their degree of color and their proportional quantity. We rarely find one which is homogeneous. We observe on the right and left side, on the limit between the two substances, a depression in which those small ducts which arise from the external substance terminate. The posterior part of this depression forms a small canal, which, converging with that of the opposite side, goes towards the centre of the posterior edge of the lobes, and the place where the infundibulum is continuous with the pituitary body ; the two canals unite in this place.

The posterior lobe has uniformly a more or less grayish tint.

Both lobes are directly attached to the infundibulum, which always descends on the upper face of the pituitary gland to the place where they unite, and are surrounded with it by a prolongation of the piamater.

The infundibulum is formed of gray substance, a continuation of that of the floor of the third ventricle, and it is considerably narrower in its centre than above and below, where it is several lines thick.

jl) A. Murray, Observationes anatomicœ circa infundibulum cerebri , ossium capitis in feetu structuram alienam partemque nervi intercostalis cervicalem, Upsal, 1772.

(2) Wenzel, Observations sur le cervelet et sur les diverses parties du cerveau dans les epileptiques , 1811. — Rayer, Observations sur les maladies de l'appendice sussphenoidal du cerveau ; in the Archiv, gen. de medecine, t. iii. p. 320. — See also the extract from Guersent’s case, same journal, v. iii. p. 312. — Ward, Case of amaurosis produced by enlargement of the pit uitary gland ; in the Land. med. repository, 1823, t. xx. p. 217.


OF THE NERVOUS SYSTEM.


439


Opinions vary in regard to the nature of the infundibulum ; some think it entirely hollow ; others on the contrary that it is solid ; and some assert that it is sometimes solid and sometimes hollow.

Although a canal is not always visible within it, as some writers have asserted, particularly the old anatomists, and Murray among the moderns ; it -is sometimes hollow in all its extent, and we can always introduce into it air or liquids, pushing them from the pituitary gland into the third ventricle ; but this is more difficult, and even fails when attempted in the opposite direction from the ventricle towards the pituitary gland. The infundibulum may serve to transmit into the cerebral ventricles, a fluid which is secreted by the pituitary gland.

Sometimes, but rarely, we find within or on the surface of the pituitary gland, a solid and sandy substance ( acervulus cerebri.){ 1)

IV. BOOT AND DECUSSATION OF THE OPTIC NERVE.

§ 1760. The larger anterior and inferior partof the rootof theoptic nerve which is the largest, and the decussation of this pair of nerves, follow the two bodies described in the preceding paragraph ; these parts are situated outwardly on the anterior extremity of the cerebral peduncles, inwards and in the centre before the grayish plate which forms the inferior wall of the third ventricle, from which the optic nerve receives in the angle formed by the union of its anterior with its posterior half, filaments which may be regarded as its anterior root.

When speaking of the optic nerve, we shall give a more detailed description of the course and union of its roots.

V. GRAY PLATE OF THE INFERIOR WALL OF THE THIRD VENTRICLE.

§ 1761. The gray plate (tuber cinereum) of the inferior wall of the third ventricle, is thicker in its posterior than in its anterior half, which is extremely thin, so that it tears very easily, merely from its weight, when the brain is turned over and all its sides are not well supported. It is continuous forward with the anterior extremity of the corpus callosum, where it forms on the surface of the anterior commissure a thin expansion, across which we perceive this cord.

II. LATERAL REGIONS.

§ 1762. The two lateral regions of the lower face of the cerebrum, are much more extensive than the central. Their internal edges touch anteriorly and posteriorly where they are separated only by the falx cerebri, while in the centre, there is a space filled by the parts we are about to describe.


(1) Bichat, Anat. descript., voL iii. p. 75.


440


descriptive anatomy.


This larger part of the lower face of the cerebrum, is formed by the lower face of the posterior and of the middle lobe. It presents a slight concavity posteriorly in all that part which corresponds to the posterior lobe, which is entirely covered by the cerebellum. Anteriorly it is slightly convex, loose, and terminated by a rounded extremity. Its anterior part projects considerably, and forms the lowest region of the cerebrum. It extends to the small wings of the sphenoid bone, and passes about an inch beyond the central part, which terminates by the decussation of the optic nerves.

This blunt anterior extremity of the middle lobe is loose, and covers the inferior extremity of the lateral part of the fissure of Sylvius. Behind it, the lower face of the middle lobe forms at first a large convex eminence, which rests outwardly on the base of the skull, and which covers within, the posterior part of the root of the optic nerve, with which it is united only by a short cellular tissue, and by the pia-mater.

This eminence is the commencement of a conical projection, which contracts from before backward, and marks in this place the transition from the external to the internal face of the cerebrum, and forms the posterior part of the inner edge of the middle lobe. The upper part of the eminence, the hook, has a direction from within outward, and from before backward, and terminates in a blunt extremity, which is continuous with the medullary semicircular band. The loose and concave edge of which is turned forward, while its attached and convex edge looks backward. This band called the corpus fimbriatum ( tÅ“nia , s. fimbria), enlarges inward and upward. When th'è cerebellum is turned downward and forward, we see very clearly that it blends with that of the opposite side, and forms the posterior part of the fornix. Below, it is a longitudinal band, which has the same direction, but is less prominent ; this is termed the fascia dentata. The latter extends forward a little farther than the preceding, and is covered by the external part of the base of the hook. It gradual^ enlarges from before backward, and presents numerous elevations and depressions situated longitudinally one after another.

The lower part of the internal edge of the lower face of the eminence which has the same direction, but which projects more, extends backward, upward, and inward, and is continuous with the posterior part of the corpus callosum. Its most internal part, which presents a convexity upward and downward, is white and smooth. The gray substance is seen where this internal part is continuous with the lower face of the cerebrum, and there also its circumvolutions commence, at least, unless we consider the fascia dentata as a rudiment, which seems more correct, inasmuch as a layer of gray substance, which communicates with the rest of the cortical substance of the brain, passes from each side to the posterior extremity of the corpus callosum on the origin of this inferior medullary layer, and is continuous with the fascia dentata. The circumvolutions arise imperceptibly in this place from the white band which we last described ; and the most internal forms a


OP THE NERVOUS SYSTEM.


441


considerable longitudinal prominence, which is not interrupted by transverse striæ, or at least by none which are very manifest.

The lower face of the anterior lobe, which is slightly concave and the internal edge of which descends much lower than the external, are situated before the anterior extremity of the middle lobe. The internal edges of the two lobes approach each other very much.

The middle lobe and the anterior lobe are separated by the internal part of the entrance of the fissure of Sylvius. This entrance corresponds entirely to the lower face. Its most internal part is loose, and is continuous with the thin plate situated before the decussation of the optic nerves; (§ 1761) it becomes broader from within outward, and is perforated with numerous considerable openings, which increase in diameter from within outward, and give passage to the vessels sent off by the origin of the middle cerebral artery into the cerebral substance. This is termed by Vicq-d’Azyr the anterior perforated substance (substantia perforata antica).{\ ) and by Reil, the cribriform plate ( lamina cribrosa).( 2)

This cribriform plate is formed almost entirely of gray substance. It is, however, white internally in its centre, whence arise the lateral longitudinal striæ of the corpus callosum, which go upward and inward. It is continuous outward and backward at the inner part of the summit of the middle lobe, and farther forward, with a small smooth elevation, about half an inch broad, where the white substance is exposed, and where the anterior and posterior lobes unite, without being separated by a deep fissure.

The olfactory nerve proceeds at a little distance in a deep groove, along the inner edge of the lower face of the anterior lobe ; its direction is from before backward, from above downward, and from without inward, and it is united to the lobe by the pia-mater, which extends like a bridge on its upper face.

The extremity of this longitudinal groove, which is much deeper than the optic nerve is high, is bounded by a triangular tubercle, the olfactory tubercle ( processus , s. carunculus mammillaris ), from whence the nerve partly arises. We also see a white band proceeding from it ; this goes backward, upward, and outward, and terminates in the fissure of Sylvius, at the union of the anterior and posterior lobes, at the point where the white substance becomes visible externally.

II. EXTERNAL FACE.

§ 1763. The external face is convex, and is most prominent in its centre on each side upward and downward. It is imperceptibly continuous with the upper and lower faces, less however with the first than with the second. Th e fissure of Sylvius divides it into an anterior

(1) Loc. cit., p. 545.

(2) Archiv. fur die Physiologie, vol. ix. p. 199.

Vol. II. 56


442


DESCRIPTIVE ANATOMY.


and a posterior half. At first view this fissure seems only an indentation, the direction of which is obliquely from below upward, and from before backward, and is situated at about the centre of the lateral face, a little nearer its anterior than its posterior extremity, the parietes of which are formed, the inferior by the upper face of the anterior part of the middle lobe ; the superior, on the contrary, by the lower face of the middle part of the anterior lobes, and we may consider its posterior extremity as the upper limit of the external face. An attentive examination, however, soon shows that it has much more extent. In fact, at the outer extremity of the anterior cribriform plate, (§ 1762) the commencement of the fissure of Sylvius, hitherto single, divides into an anterior and a posterior groove. The posterior is that just described. The anterior is much shorter, goes directly upward, and communicates with the posterior extremity of the posterior, by a third groove, which proceeds directly from before backward. These three grooves consequently include a triangular space, the lower part of which is seen where we separate the two parietes of the posterior groove ; but we cannot see its whole extent until we have opened the superior horizontal groove, by raising that part of the anterior lobe which forms it anteriorly. We then observe that the central part of the anterior lobe, at first convex, goes from below upward into this middle portion of the fissure of Sylvius, and thus forms a triangular space called the island of the fissure of Sylvius , then immediately descends again before its larger upper part, resting upon it, then describes a right angle to go directly outward for about an inch, and finally joins, also at a right angle, the external face of the hemisphere, and particularly of the anterior lobe. The lower and horizontal