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Book IV. Angiology

§ 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.



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.





§ 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.


§ 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.



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.


§ 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 )


§ 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.





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.


§ 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.



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



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.



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.



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.


§ 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.



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.



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.


§ 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.



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.


§ 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



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




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.


§ 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.



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.



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.



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.



§ 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.


§ 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



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



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 Mè 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.




§ 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





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.


§ 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



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.


§ 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.




§ 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,



§ 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.



§ 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.



§ 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.



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. 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



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.


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.






22 4








15 4



32 4

28 4


22 4


20 4



41 4

21 4



2 4

1 4

1 4

1 6

1 6


1 6

1 2

1 4


together 4 ounces.



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.)



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.


§ 1315. The only sexual difference seen in the heart is that it is proportionally a little larger in males.



§ 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



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.



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




§ 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.



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.



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.



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.



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.



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



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.



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.



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.


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.






§ 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.


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).



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)



§ 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.





§ 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




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.



§ 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.



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,



§ 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..'



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.



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



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.



§ 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.



§ 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.


§ 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.



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.


§ 1347. The anterior branches are the superior thyroid artery, thtr lingual artery, and the facial 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



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.


§ 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).



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.


§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.



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



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



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.



§ 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



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.


§ 1354. The posterior branches of the external carotid artery are, 1st the occipital , and 2d the posterior auricular 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.



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.)


§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



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.


§ 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.


§ 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).

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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.



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.


§ 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.



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.



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.



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.


§ 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.



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.


§ 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.



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.



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.

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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.


§ 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.



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.



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.



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.



§ 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.



arise on each side by a single trunk, generally called the subclavian arteiy (A. subclavia).


§ 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.




§ 1374. The most constant of the upper and posterior branches are two, the vertebral artery and the inferior thyroid 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.



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.



§ 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


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



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.


§ 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.



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



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.


§ 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



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.


§ 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.


§ 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.



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.


§ 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 .



§ 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).


§ 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).




§ 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.


§ 1397. The inferior branches of the subclavian artery are the internal mammary artery and the superior intercostal 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.

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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 descen