Book - Buchanan's Manual of Anatomy including Embryology 10

From Embryology
Revision as of 08:37, 20 July 2020 by Z8600021 (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Embryology - 28 Sep 2020    Facebook link Pinterest link Twitter link  Expand to Translate  
Google Translate - select your language from the list shown below (this will open a new external page)

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

Frazer JE. Buchanan's Manual of Anatomy, including Embryology. (1937) 6th Edition. Bailliere, Tindall And Cox, London.

Buchanan's Manual of Anatomy: I. Terminology and Relative Positions | II. General Embryology | III. Osteology | IV. Bones of Trunk | V. Bones of Head | VI. Bones of Upper Limb | VII. Bones of Lower Limb | VIII. Joints | IX. The Upper Limb | X. Lower Limb | XI. The Abdomen | XII. The Thorax | XIII. Development of Vascular Systems | XIV. The Head and Neck | XV. The Nervous System | XVI. The Eye | XVII. The Ear | Glossary
Historic Disclaimer - information about historic embryology pages 
Mark Hill.jpg
Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

Chapter X The Lower Limb

The Gluteal Region

Landmarks. — The crest of the ilium is almost entirely obscured by the prominence of the abdominal muscles above it and the gluteus medius below it, its position being usually indicated by a depression. By following this depression backwards, the posterior superior iliac spine, which is on a level with the second sacral spine and the centre of the sacro-iliac joint, may be found. In the mid-dorsal line the spinous processes of the sacral vertebrae, usually four in number, may be distinguished as separate projections, or they may be fused together into i median ridge which, as the fifth sacral spine is undeveloped, terminates ibruptly below. At a slightly lower level and on either side of the niddle line the sacral cornua may be detected. The coccyx can be felt in the natal cleft between the buttocks. The ischial tuberosity is inder cover of the gluteus maximus when the hip-joint is extended, 3ut when that joint is flexed, its prominence can be easily distinguished, rhe greater trochanter can be felt at the lower and outer part of the gluteal region; its situation corresponds to a surface depression. The Drominence of the buttock is due to the gluteus maximus, and a thick nass of fatty tissue covering it superficially. The gluteal fold is a skin fold limiting the buttock prominence below; it is very obvious when he hip-joint is extended, but disappears when the joint is flexed. It is horizontally disposed, and practically bisects the obliquely disposed ower edge of the gluteus maximus. In a thin subject it is sometimes Dossible to feel the sciatic nerve in this fold, as that nerve lies deeply it a point very nearly midway between the greater trochanter and schial tuberosity, being rather nearer the latter than the former.

The Cutaneous Nerves (Fig. 329) are met with in the following situations: (1) Along the line of origin of the gluteus maximus; 2) crossing the iliac crest; (3) on the outer and lower part of the gluteus maximus; and (4) crossing the lower border of the gluteus naximus.

1. Along the Line of Origin of Gluteus Maximus. —The nerves are lisposed in three sets:

[a) Two or three twigs from the lateral branches of the posterior primary divisions of the first three sacral nerves. From communica:10ns between these lateral branches two sets of loops are derived, Dne set being situated deeply on the back of the sacrum, and the other >et more superficially on the posterior surface of the sacro-tuberous ligament. From the latter set of loops two or three cutaneous twigs are derived, and pass outwards through the substance of the gluteus maximus.



Fig. 329. - Muscles and Cutaneous Nerves of the Lower Limb (Posterior Aspect).


{b) The posterior primary divisions of the last two sacral nerves and the coccygeal nerve form a loop on the back of the sacrum, from which cutaneous twigs are given off and are distributed to the skin on the back of the coccyx.


(c) Branches from the coccygeal plexus, which is situated on the pelvic surface of the coccygeus muscle, traverse the coccygeus muscle, the sacro-spinous and sacro-tuberous ligaments, and the gluteus maximus successively, and are distributed to the skin on the back of the coccyx.

2. Crossing the Iliac Crest.— The lateral branches of the posterior primary divisions of the first three lumbar nerves descend over the iliac crest in front of the outer border of the sacro-spinalis muscle. The lateral cutaneous branch of the ilio-hypogastric nerve crosses the iliac crest at the junction of the middle and anterior thirds, the most prominent point of the tubercle of the crest being a guide to its position.

The lateral cutaneous branch of the subcostal nerve descends over the anterior part of the iliac crest 1 inch behind the anterior superior iliac spine, and is distributed to the skin of the anterior part of the gluteal region as low as the greater trochanter.

3. Outer and Lower Part of Gluteus Maximus. —Branches of the posterior division of the lateral cutaneous nerve of the thigh.

4. Crossing the Lower Border of Gluteus Maximus. —Three or four recurrent branches from the posterior cutaneous nerve of thigh supply the skin over the lower and outer part of the gluteus maximus. The perforating cutaneous branch of the sacral plexus, usually derived from the second and third sacral nerves, traverses the sacro-tuberous ligament, winds round the lower edge of the gluteus maximus, and supplies the skin over the lower and inner part of the muscle.

Fasciae. —The superficial fascia is loaded with fat. It is continuous over the iliac crest with the superficial fascia of the back of the trunk, and largely contributes to the prominence of the buttock. Between the iliac crest and the upper border of the gluteus maximus a considerable amount of fatty tissue occupies a depression in this situation. The deep fascia investing the gluteus maximus is thin, but at the insertion of the muscle and over the anterior two-thirds of the gluteus medius it is thick and dense. In these latter situations it gives insertion to a considerable part of the gluteus maximus, and the superficial fibres of the gluteus medius arise from its deep aspect. As it passes from the gluteus maximus on to the gluteus medius it straps down the upper border of the former muscle.

Muscles—Gluteus Maximus (Fig. 329)— Origin. —The posterior 2 inches of the outer lip of the iliac crest; the upper part of the rough surface on the gluteal surface between the crest and the posterior gluteal line; the posterior layer of the lumbar fascia; the dorsal aspects of the fourth and fifth sacral vertebrae and of the upper three coccygeal vertebrae; and the sacro-tuberous ligament.

Insertion .—The upper part and the superficial fibres of the lower part of the muscle are inserted into the ilio-tibial tract, a thickened band of the fascia lata on the outer side of the thigh, attached above to the tubercle of the iliac crest and below to the lateral condyle of the tibia and the head of the fibula. The deep fibres of the lower part of the muscle are inserted into the gluteal tuberosity of the femur.


Nerve-supply .— The inferior gluteal nerve, a branch of the sacra plexus, enters the deep surface of the muscle.

The muscle is very coarsely fasciculated. Its general direction is downwards and outwards.

Action .—Acting from its origin, the muscle extends the thigh upor the trunk. The upper part abducts the thigh, and the lower pari adducts it and rotates it outwards. By means of the ilio-tibial tract the muscle also takes part in completing and maintaining extension of the knee-joint. Acting from its insertion, the muscle extends the trunk upon the thigh.

The gluteus maximus is quadrilateral; it has a short upper border bound down to the gluteus medius by the fascia lata, and a longer lower border.

Deep Relations .—The back of the sacrum and coccyx, the hinder part of the ilium, the ischia] tuberosity when the hip-joint is extended, the hinder aspect of the greater trochanter, and the upper end of the shaft of the femur; the posterior sacro-iliac ligaments and the sacro-tuberous and sacro-spinous ligaments; the following muscles from above downwards: gluteus medius, pyriformis, obturator internus and the two gemelli, quadratus femoris and upper part of the adductor magnus, lateral to the two latter muscles the upper part of the vastus lateralis, and medial to them the origins of the hamstrings; above the pyriformis the superior gluteal vessels and superior gluteal nerve, and below that muscle the sciatic, posterior cutaneous of thigh, inferior gluteal, and pudendal nerves, the nerv'es'Ao quadratus and obturator internus, the inferior gluteal and internal pudendal vessels, between the quadratus femoris and adductor magnus the transverse branch of the medial femoral circumflex artery.

Three synovial bursae may be found on the deep aspect of the muscle. An inconstant one is situated between the lower border of the muscle and the ischial tuberosity. Another lying between the muscle and the greater trochanter is occasionally present. The third is large and constant, and is found between the muscle and the upper part ol the vastus lateralis, just below the greater trochanter.


Fig. 330.—Showing the Arrangement of Gluteus Maximus (GM), Tensor Fascle Lat,e (T), and Gluteal Aponeurosis (GA), all converging on an Aponeurotic Band, the Iliotibial Tract (IT).


The gluteus maximus is relatively a larger muscle in man than in any othe animal. Its extensive attachment to the deep fascia is also a human peculiarity it is essentially a muscle of the erect attitude, in which it plays an importan part by its actions on the hip and knee joints.


Gluteus Medius (Fig. 331)— Origin .—An area on the gluteal surfa( 01 the ilium bounded by the crest, posterior gluteal line, and middle gluteal line; and the fascia lata covering the anterior two-thirds of the muscle.

Insertion .—The oblique impression on the outer surface of the greater trochanter, extending from the postero-superior angle downwards and forwards to the antero-inferior angle.

Nerve-supply .—The superior gluteal nerve.


Pyriformis


Add. Mag.


Obt. Int. and Gemelli Obt. Externus Fem.


Hamstrings


The direction of the anterior fibres of the muscle is downwards and slightly backwards, and of the posterior fibres downwards and forwards. The fibres of the muscle converge from their origin to the fan-shaped tendon of insertion; they correspond in direction with those of the gluteus minimus.

Action . — Acting from its origin, the muscle abducts the thigh. The anterior fibres, contracting independently, rotate the thigh inwards.


Fig. 331. — Muscles of the Gluteal Region.

Gluteus maximus divided and turned back. Sciatic nerve and inferior gluteal artery introduced to show their position.



while the posterior fibres rotate it outwards. Acting from its insertion, it rotates and bends the trunk to the same side; it is an important balancing muscle.

The muscle is triangular. The posterior fleshy third is covered by the gluteus maximus, and the anterior two-thirds by the fascia lata. The muscle lies superficially to the gluteus minimus, the deep division of the superior gluteal artery and the superior gluteal nerve lying between them. A synovial bursa intervenes between it and the upper part of the greater trochanter.

Gluteus Minimus — Origin. —The gluteal surface of ilium between the middle and inferior gluteal lines.

Insertion. —A depression on the anterior aspect of the greater trochanter.

Nerve-supply. — The lower division of the superior gluteal nerve.

The fibres of the muscle correspond in direction, for the most part, with those of the gluteus medius.

The Action is similar to that of the gluteus medius (q.v.).

The muscle is fan-shaped, and the tendon of insertion spreads out into an aponeurotic expansion over its lower part. It is covered superficially by the gluteus medius. Its deep surface is related to the capsular ligament of the hip-joint and the reflected head of the rectus femoris. The tendon of insertion of the muscle is separated from the greater trochanter by a synovial bursa, and is connected with the upper part of the capsular ligament of the hip-joint by a strong arched band of fibres.

The anterior portion of the gluteus minimus is sometimes detached from the rest of the muscle, and when this occurs, the separated part represents the gluteus quartus or musculus scansorius (climbing muscle) of certain animals.

Pyriformis (Fig. 331)— Origin. —By three fleshy slips from the anterior surfaces of the second, third, and fourth sacral vertebrae, the slips lie between and lateral to the anterior sacral foramina; the deep surface of the sacro-tuberous ligament; and the posterior border of the ilium immediately below the posterior inferior iliac spine.

Insertion. —A flattened area on the upper border of the greater trochanter.

N erv e-supply .— Branches from the first and second sacral nerves enter the intrapelvic part of the muscle.

Action. —A lateral rotator of the thigh.

As the pyriformis emerges from the pelvic cavity through the greater sciatic foramen it divides the latter into a smaller upper and a larger lower compartment. In the upper compartment are the superior gluteal vessels and superior gluteal nerve. In the lower compartment the inferior gluteal and internal pudendal vessels, sciatic and posterior cutaneous nerves, inferior gluteal nerve, pudendal nerve, nerve to obturator internus, and common nerve to^gemellus inferior and quadratus femoris.


Gemellus Superior (Fig. 331)— Origin.— The outer and lower part of the spine of the ischium.

Insertion. —The upper border of the tendon of the obturator internus, with which it is inserted.

Nerve-supply—A branch from the nerve to the obturator internus, which enters the muscle on its deep surface and close to its origin.

The gemellus superior is often very small and is sometimes absent.

Obturator Internus (Fig. 331)— Origin— The deep surface of the obturator membrane except in its lower part; the pelvic aspect of the bone both above and medial to the obturator foramen, and between the foramen and the greater sciatic notch; and slightly from the

obturator fascia covering the muscle.

Insertion. —To a depression on the inner surface of the greater trochanter, above and in front of the trochanteric fossa.

Nerve-supply. —The nerve to the obturator internus derived from the fifth lumbar and the first and second sacral nerves.

Action .—A lateral rotator of the thigh.

The intrapelvic and extrapelvic parts of the muscle are disposed at very nearly a right angle to each other, the tuberosity of the ischium playing the part of a pulley for the muscle. It emerges from the pelvic cavity through the lesser sciatic foramen, and in this situation the deep surface of its tendon is subdivided into froln three to five bands, with linear grooves between them. The bone upon which these tendons lie is covered by cartilage, which presents as many grooves as there are tendons. A bursa intervenes between the tendons and the cartilage covering the bone.

Gemellus Inferior (Fig. 331)— Origin .—The part of the ischial tuberosity forming the lower margin of the lesser sciatic notch.

Insertion. —The lower border of the tendon of the obturator internus, with which it is inserted.

Nerve-supply.— A branch from the nerve to the quadratus femons, which enters the muscle on its deep surface near its origin.

The gemelli are extrapelvic parts of the obturator internus. Ihe two muscles are not only attached to the upper and lower borders of the obturator tendon, but also overlap and partially conceal the tendon on its superficial aspect.

Lesser Sciatic Foramen.— The structures occupying this foramen are the obturator internus muscle; the pudendal nerve and the nerve to the obturator internus; and the internal pudendal vessels.

Quadratus Femoris (Fig. 331)—

Origin. — The outer border of the ischial tuberosity.

Insertion. —The quadrate eminence and the quadrate line of the

femur.

Nerve-supply. —The nerve to the quadratus femoris, derived from the fourth and fifth, lumbar and the first sacral nerves.

Action .—A lateral rotator of the thigh.


The muscle lies superficially to a part of the obturator externus and the lesser trochanter of the femur, being separated from the latter by a small bursa. If the gemellus inferior and quadratus femoris are separated, the obturator externus comes into view. Between the lower border of the muscle and the upper border of the adductor magnus is the transverse branch of the medial femoral circumflex artery. If the lower border of the muscle is raised, the lesser trochanter with the tendon of insertion of the ilio-psoas come into view.

Arteries. —The chief arteries of the gluteal region are the superior and inferior gluteal and the internal pudendal.

The Superior Gluteal Artery (Fig. 332) arises from the posterior division of the internal iliac artery. Traversing the parietal pelvic fascia, it passes between the lumbo-sacral trunk and the anterior primary division of the first sacral nerve, and emerges from the pelvic cavity through the upper compartment of the greater sciatic foramen above the pyriformis, where it divides into two divisions—superficial and deep. From the trunk of the artery the chief nutrient artery to the ilium is given off. The superficial division passes backwards between the posterior border of the gluteus medius and the pyriformis, and enters the deep or anterior surface of the gluteus maximus near its origin. Some of its branches become cutaneous by piercing the muscle, and anastomose with the posterior branches of the lateral sacral arteries derived from the posterior division of the internal iliac.

The deep division lies deeply to the gluteus medius, where it subdivides into two branches, an upper and a lower. The superior branch courses along the upper border of the gluteus minimus, following the middle curved line of the ilium in company with the upper division of the superior gluteal nerve. It supplies the ilium and adjacent muscles, and terminates in the region of the anterior superior iliac spine, where it anastomoses with the deep circumflex iliac of the external iliac and the ascending branch of the lateral femoral circumflex of the arteria profunda femoris. The inferior branch crosses the middle of the gluteus minimus in company with the lower division of the superior gluteal nerve. It supplies the gluteus medius and gluteus minimus, the muscles between which it lies. It gives an articular branch to the hip-joint, and a branch to the trochanteric fossa which anastomoses with the inferior gluteal, an ascending branch of the medial femoral circumflex, and a branch of the first perforating artery. It also anastomoses with the ascending branch of the lateral femoral circumflex.

The place of emergence of the superior gluteal artery from the pelvis is indicated as follows: the thigh being rotated inwards, draw a line from the top of the greater trochanter to the posterior superior iliac spine, and take a point in this line at the junction of the inner third and outer two-thirds.

The Superior Gluteal Vein. —As the artery occupies the upper part of the greater sciatic notch it is surrounded by a dense plexus of veins, which join the internal iliac vein.



Fig. 332.—The Gluteal Region and Back of the Thigh (Deep Dissection).


The Inferior Gluteal Artery arises from the anterior division of the internal iliac artery. In the pelvis it descends behind the internal pudendal, lying in front of the pyriformis and sacral nerves, and emerges through the lower compartment of the greater sacro-sciatic foramen below the pyriformis. It passes downwards between the greater trochanter and ischial tuberosity to the inner side of the sciatic nerve, lying deeply to the gluteus maximus, and superficially to the gemelli, obturator internus, and quadratus femoris.

Branches.—The extrapelvic branches are as follows:

The coccygeal branch traverses the sacro-tuberous ligament and gluteus maximus, and is distributed over the back of the coccyx. One branch enters the deep surface of the gluteus maximus with the inferior gluteal nerve, and anastomoses in the substance of the muscle with the superficial division of the superior gluteal artery. The muscular branches are distributed to the adjacent lateral rotator muscles and the origins of the hamstrings.

The anastomotic branches are two in number. One passes to the trochanteric fossa, where it anastomoses with the superior gluteal, ascending branch of the medial femoral circumflex, and first perforating arteries. The other passes to the interval between the quadratus femoris and adductor magnus, where it anastomoses with the transverse branch of the medial femoral circumflex, the transverse branch of the lateral femoral circumflex, and the first perforating artery. This fourfold anastomosis is called the crucial anastomosis, but cannot always be recognized.

The articular branches are two or three in number. They pass deeply to the gemelli and obturator internus with the nerve to the quadratus femoris, and supply the hip-joint from behind.

The gluteal cutaneous branches wind round the lower border of the gluteus maximus with the gluteal cutaneous branches of the posterior cutaneous nerve of the thigh, and are distributed to the skin covering the lower part of the muscle.

The femoral cutaneous branch descends with the posterior cutaneous nerve of the thigh, and supplies the skin on the back of the thigh.

The companion artery of sciatic nerve is a long branch which descends for some distance with the sciatic nerve, to which it is distributed, and in which it anastomoses with the perforating branches of the arteria profunda femoris.

The place of emergence of the inferior gluteal artery from the pelvic cavity is indicated by a point at the junction of the middle and lower thirds of a line drawn from the posterior superior iliac spine to the outer border of the ischial tuberosity.

The inferior gluteal vein terminates in the internal iliac vein.

The inferior gluteal artery in the early embryo is the main arterial trunk supplying the lower limb. As the femoral artery is developed it effects a junction with the inferior gluteal in the neighbourhood of the knee, and by transmitting blood to the distal part of the limb eventually becomes the chief artery. The trunk of the primitive sciatic between the knee and the gluteal region for the most part disappears.


The internal pudendal artery (Fig. 332) arises from the anterior division of the internal iliac, and at first lies within the pelvic cavity. The second part of the vessel appears in the gluteal region, and will be described here. It emerges from the pelvic cavity through the lower compartment of the greater sacro-sciatic foramen below the pyriformis, and, passing downwards for a short distance, crosses the back of the spine of the ischium. It leaves the gluteal region by passing through the lesser sacro-sciatic foramen.

Relatione —Superficial or Posterior .—Gluteus maximus. Deep or Anterior .—The spine of the ischium.

The artery is accompanied by two venae comites. The pudendal nerve lies on its inner side, and the nerve to the obturator internus on its outer side.

Branches.—Muscular, to gluteus maximus.

The position of the second part of the internal pudendal artery, as it lies upon the back of the spine of the ischium, is about 4 inches below the posterior superior iliac spine, and is indicated on the surface by rotating the thigh inwards, and taking a point at the junction of the inner third and outer two-thirds of a line drawn from the upper border of the greater trochanter to the junction of the sacrum with the coccyx.

Deep Nerves.—The superior gluteal nerve (Fig. 332) arises from the fourth and fifth lumbar and the first sacral nerves. It passes through the upper compartment of the greater sacro-sciatic foramen, above the pyriformis, in company with the superior gluteal artery, and passes outwards between the gluteus medius superficially and the gluteus minimus deeply, where it divides into a smaller upper and a larger lower branch. The upper branch accompanies the upper deep branch of the superior gluteal artery, and supplies the gluteus medius. The lower branch crosses the middle of the gluteus minimus, and accompanies the lower deep branch of the superior gluteal artery. It supplies the gluteus medius and gluteus minimus, and ends by supplying the tensor fasciae latae.

It may be noticed that the three muscles supplied by the superior gluteal nerve are all concerned in rotating the thigh inwards, a movement brought about by, amongst other muscles, the anterior fibres of the gluteus medius and minimus and the tensor fasciae latae.

The inferior gluteal nerve (Fig. 332) arises from the fifth lumbar and first and second sacral nerves. It passes through the lower compartment of the greater sacro-sciatic foramen, below the pyriformis, and in close contact with the sciatic nerve. It divides into several branches which enter the deep surface of the gluteus maximus.

The nerve to obturator internus arises from the fifth lumbar and first and second sacral nerves. It passes through the lower compartment of the greater sacro-sciatic foramen, below the pyriformis, and medial to the sciatic nerve and posterior cutaneous nerve of the thigh. It winds round the spine of the ischium, where it lies to the outer side of the sciatic internal pudendal vessels, and, passing through the lesser sacroforamen, is finally distributed to the intrapelvic part of the obturator internus. At the lower border of the pyriformis it gives a branch to the gemellus superior, which enters the deep surface of the muscle close to its origin.

The nerve to quadratus femoris arises from the fourth and fifth lumbar and the first sacral nerves. It passes through the lower compartment of the greater sacrosciatic foramen, below the pyriformis, where it lies in close contact with the deep surface of the sciatic nerve. It passes downwards, lying directly on the bone, and covered on its superficial or posterior aspect by the gemellus superior, obturator internus, gemellus inferior, and quadratus femoris. It enters the deep surface of the quadratus femoris near its upper border and close to its origin. It gives a branch to the gemellus inferior, which enters its deep surface near its upper border and close to its origin.

The nerve to the quadratus femoris usually supplies an articular branch to the back of the hip-joint.

Lymphatics.—The superficial lymphatics of the gluteal region terminate in the superficial inguinal glands. The deep lymphatics enter the pelvic cavity and terminate in the internal iliac glands.


The Thigh

Back of the Thigh and Popliteal Space.

Landmarks.—The hamstring muscles are responsible for the prominence on the back of the thigh, but can only be recognized individually in the region of the knee. The sciatic nerve is deeply placed, being under cover of the long or ischial head of the biceps femoris; its course


Biceps (B) and semitendinosus (T) have a common origin from ischial tuberosity and from septum (S). The femoral head of biceps is seen lower down. M, semimembranosus. . .. r

may be indicated by drawing a line from

the centre of the back of the knee-joint to a point between the greater trochanter and the ischial tuberosity, rather nearer the latter than the former. The upper two-thirds of this line corresponds with the sciatic nerve, and the lower third with the medial popliteal nerve.

The situation of the popliteal fossa behind the knee-joint is indicated by a depression when the joint is flexed. The strong tendon of the biceps femoris descending to the head of the fibula can be felt on the outer side and in front of it; the lateral ligament of the knee-joint can be distinguished as a tense rounded cord on the outer side of the knee. Anterior to this ligament the lower part of the ilio-tibial tract, which may easily be mistaken for a tendon, can be felt. The lateral popliteal nerve is close to the inner side of the biceps tendon. Lower down it winds round to the front of the limb just below the head of the fibula. On the inner side of the popliteal fossa, over the back of the inner medial, three tendons may be felt. The most superficial is that of the semitendinosus, which is narrow and resistant; it is traceable for some distance above the knee-joint. Deeply to it is the tendon of the semimembranosus, and medial to this is the slender tendon of the gracilis. The course of the popliteal artery coincides with the middle line of the popliteal fossa, but the vessel can only be felt when the joint is well flexed. In this position of the joint the popliteal lymphatic glands, if enlarged, may be detected.

Back of the Thigh.—The posterior cutaneous nerve of the thigh (Fig. 334) arises from the first, second, and third sacral nerves. It escapes from the pelvic cavity through the lower compartment of the greater sacrosciatic foramen, below the pyriformis. Passing downwards between the greater trochanter and ischial tuberosity, and under cover of the lower part of the gluteus maximus, it is at first a close companion of the sciatic nerve. After escaping from under cover of the gluteus maximus, it descends in the middle line of the back of the thigh superficial to the hamstring muscles and deep to the fascia lata covering them. Extending downwards to the popliteal space, it traverses the deep fascia at the back of the knee. Thence it descends on to the back of the leg in company with the short saphenous vein, and terminates on the back of the calf. The nerve is entirely cutaneous in its distribution.



Fig. 334 — Dissection showing Cutaneous Gluteal Nerves.

a, b, Lumbar and sacral, post, primary; T, Last thoracic; L, Ilio-hypogast.; M, Glut, max.; LC, Lat. cutan.; GR. Gracilis; P, Perforating; A, Add. magn.; G, Recurr. gluteal (of post fern, cut.); ST, Semitend.; SM, Semimemb.; B, Biceps.

The posterior cutaneous nerve of the thigh is shown for some distance running down superficial to muscles; it is immediately under deep fascia.


Branches. —The gluteal cutaneous branches, three or four in number, take a recurrent course, wind round the lower border of the gluteus maximus, and supply the skin covering the lower and outer part of the muscle. The perineal branch arises under cover of the gluteus maximus, and winds inwards towards the anterior part of the perineum; it lies some little distance below the ischial tuberosity, and crosses the origins of the hamstring muscles. It pierces the fascia lata fully i inch in front of the ischial tuberosity, and, passing over the ischio-pubic ramus through the deeper layer of the superficial perineal fascia, it courses forwards and inwards in company with the two superficial perineal nerves and the superficial perineal artery, being finally distributed to the scrotum in the male and the labium majus in the female. In the anterior part of the perineum it communicates with the two superficial perineal nerves, and with them forming one of the three posterior scrotal (or labial) nerves. Its branches are femoral cutaneous , to the upper and inner part of the thigh on its posterior aspect; and scrotal or labial, to the scrotum or labium majus, according to sex. The femoral cutaneous are a series of branches supplying the skin of the back of the thigh as low as the knee. The sural cutaneous are the terminal branches of the nerve. They supply the skin of the upper part of the back of the leg, and communicate with the sural nerve, a branch of the internal popliteal nerve.

Muscles. — The muscles of the back of the thigh are usually termed the hamstring muscles, and are three in number.

Biceps Femoris (Figs. 333, 334)— Origin .—The muscle arises by two heads—the long or ischial, and the short or femoral. (1) The long or ischial head arises, in common with the semitendinosus, from the lower and inner impression on the posterior surface of the ischial tuberosity; some of the fibres of the tendon of origin are continuous with the sacrotuberous ligament.

In many animals the biceps femoris is a vertebro-crural muscle extending from the caudal end of the vertebral column to the leg. The sacro-tuberous ligament represents, partially at all events, the proximal end of the muscle, which has acquired a secondary attachment to the tuberosity of the ischium.

(2) The short or femoral head arises from the outer lip of the linea aspera, the upper two-thirds of the lateral supracondylar line, and the lateral intermuscular septum.

Insertion . — The tendon descends on the outer side of the kneejoint superficial to the upper part of the lateral ligament of the kneejoint, a bursa being interposed between the two. Some little way above the upper end of the fibula the tendon splits into two parts, anterior and posterior, which embrace the lower end of the lateral ligament. The anterior part is attached to the head of the fibula, and is prolonged forwards on to the lateral condyle of the tibia; the posterior is also attached to the head of the fibula; an expansion from it passes downwards and blends with the deep fascia on the outer side of the leg.

Nerve-supply .— The sciatic nerve. The long or ischial head receives branches from the medial popliteal part of the nerve, and the short or femoral head from the lateral popliteal part.

It is to be noted that the short head of the muscle receives its supply from a nerve (the lutcYcil popliteal part of the sciatic) which is exclusively concerned in supplying extensor muscles. The short head is undoubtedly a derivative from the extensor musculature which has been displaced to the opposite side of the limb, and has there become associated with the flexor muscles anatomically and functionally.

Action— Acting from its origin, the ischial head of the muscle extends the hip-joint; the two heads flex the leg upon the thigh. Acting from its insertion, the ischial head extends the trunk upon the thigh.

Semitendinosus (Fig. 333 )—' Origin.— The lower and inner impression on the posterior surface of the ischial tuberosity, in common with the long or ischial head of the biceps femoris.

Insertion .— The upper part of the medial surface of the shaft of the tibia, behind and below the sartorius and below the gracilis. From the tendon of insertion an expansion is given to the deep fascia of the leg.

Nerve-supply. —Sciatic nerve. The branches come from the medial popliteal part of the nerve.

Action. —Acting from its origin, the muscle extends the hip-joint, and flexes the leg upon the thigh; it also acts as a medial rotator of the leg. Acting from its insertion, it extends the trunk upon the thigh. The semitendinosus is inseparable from the long head of the biceps in the upper part of the thigh; its belly is interrupted about its middle by an oblique tendinous intersection. In the lower third of the thigh the muscle has a long, narrow, round tendon, which crosses the medial ligament of the knee-joint superficially, and broadens out at its insertion. A bursa intervenes between it and the ligament, and also between it and the tendon of the sartorius.

Semimembranosus (Fig. 333)— Origin. —By means of a broad, flat tendon from the upper and outer impression on the posterior surface of the ischial tuberosity.

Insertion .— By means of a strong tendon into a horizontal groove on the medial condyle of the tibia. At its insertion the tendon is at right angles to the rest of the muscle. From its tendon an expansion passes obliquely upwards and outwards to the upper and back part of the lateral condyle of the femur, and forms an accessory ligament on the back of the knee-joint, known as the oblique posterior ligament. Another expansion passes downwards and outwards to the soleal or popliteal line on the posterior surface of the shaft of the tibia and covers the popliteus muscle.


Nerve-supply .—Sciatic nerve. The branches come from the media] popliteal part of the nerve.

Action .—Acting from its origin, the muscle extends the hip-joint and flexes the leg upon the thigh. Acting from its insertion, it extends the trunk upon the thigh.

The tendon of origin is prolonged downwards for some distance on the outer side of the muscle, and the tendon of insertion is prolonged upwards for some distance on its inner side. The muscle fibres are short, and pass obliquely from the tendon of origin to the tendon of insertion. This arrangement increases its power, but limits its range of movement. A large bursa, common to it and the medial head of the gastrocnemius, and usually continuous with the synovial membrane through a deficiency in the posterior ligament, underlies the tendon at the back of the knee-joint. The tendon of insertion lies deeply to the medial ligament of the knee-joint, and is separated by a bursa from the upper lip of the groove on the medial condyle of the tibia.

The hamstring muscles descend in close contact with one another in the upper part of the thigh, being held together by the fascia lata. In the lower part of the thigh they part company, the biceps femoris passing downwards and outwards, and the semitendinosus and semimembranosus downwards and inwards; as the muscles diverge from one another the popliteal fossa opens out between them.

The sciatic nerve arises from the fourth and fifth lumbar, and the first, second, and third sacral nerves. It escapes from the pelvic cavity through the lower compartment of the greater sacro-sciatic foramen, below the pyriformis, and passes downwards between the greater trochanter and ischial tuberosity, being somewhat nearer the latter than the former. It descends in the middle line of the back of the thigh, deeply to the long head of the biceps, and ends, about the junction of the middle and lower thirds of the thigh, by dividing into the medial and lateral popliteal nerves. The sciatic is the largest nerve in the body, and is about £ inch broad.

Chief Relations —Superficial or Posterior .—Gluteus maximus, and the long head of the biceps femoris. Deep or Anterior .—From above downwards the nerve is in contact with the following structures: the ischium, with the nerve to the quadratus femoris intervening between them, gemellus superior, obturator internus, gemellus inferior, quadratus femoris, and the posterior surface of the adductor magnus. Medially. —Semimembranosus.

Branches. —The muscular branches arise in the upper part of the thigh, with the exception of the branch to the short head of the biceps femoris, which arises at a lower level. They supply the hamstring muscles, and also that part of the adductor magnus which descends from the ischial tuberosity to the adductor tubercle of the femur. The branch to this part of the adductor magnus arises in common with the nerve to the semimembranosus. The branch to the short head of the biceps femoris is derived from the lateral popliteal part of the nerve, all the other muscular branches come from the lutevul popliteal part.

The terminal branches are the medial and lateral popliteal nerves. They arise at about the junction of the middle and lower thirds of the thigh.

The sciatic nerve supplies the hip-joint when the articular branch of the nerve to the quadratus femoris is absent.

The sciatic nerve may divide into the lateral and medial popliteal trunks at a higher level than is usually the case, and in some instances before it leaves the pelvic cavity. In the latter case the lateral popliteal nerve often traverses the pyriformis.



Fig - 335 - The Popliteal Space (Superficial Dissection).

The popliteal fossa (Fig. 335) is situated behind the knee-joint, whence it extends upwards on to the back of the thigh, and downwards to the upper part of the back of the leg. In outline the space resembles a diamond.

Boundaries—Lateral— Above the Knee-joint. — Biceps femoris. Below the Knee-joint. —The outer head of the gastrocnemius, and the plantaris.

Medial— Above the Knee-joint. — Semitendinosus and semimembranosus. Below the Knee-joint. —The inner head of the gastrocnemius.

The upper angle of the space corresponds with the point of divergence of the hamstring muscles; the lower angle to the approximation of the outer and inner heads of the gastrocnemius; the outei angle to the meeting between the biceps femoris and lateral head ol the gastrocnemius; and the medial angle by the meeting between the semimembranosus and medial head of the gastrocnemius.

The roof is formed by the skin, subcutaneous tissue, and popliteal fascia. It contains the posterior cutaneous nerve of the thigh.

The floor is formed, from above downwards, by the popliteal surface of the femur, the posterior ligament of the knee-joint, and the popliteus muscle.

Contents. —The contents are the popliteal artery and its branches, the popliteal vein and its tributaries, the medial and lateral popliteal nerves and their branches, the genicular branch of the obturator nerve (inconstant), lymphatic glands, and a large amount of fat.

The popliteal artery (Fig. 336) is the continuation of the femoral artery, and extends from the femoral opening in the adductor magnus to the lower border of the popliteus muscle, where it divides into anterior and posterior tibial arteries. The division takes place on a level with the lower border of the tubercle of the tibia, and fully if inches below the level of the upper surface of the bone. It first passes downwards and outwards until it reaches the middle line of the limb. It then takes a straight course downwards between the condyles of the femur, and finally disappears from view under cover of the gastrocnemius muscle.

In the popliteal fossa the popliteal artery is comparatively superficial, and can be easily approached from the surface. As the lower edge of the popliteus muscle is considerably below the level of the lower angle of the fossa the lower end of the vessel is deeply placed, being covered by the thick mass of the gastrocnemius muscle.

General Relations —Superficial or Posterior. —Skin, superficial and deep fasciae, posterior cutaneous nerve of the thigh, terminal part of the short saphenous vein, the semimembranosus muscle for a short distance below the level at which the artery passes through the adductor magnus; the gastrocnemius and the plantaris lie superficially to the artery below the lower angle of the fossa. Deep or Anterior .—The popliteal surface of the femur, posterior ligament of the knee-joint and popliteus muscle.

In the upper part of the space the popliteal vein is superficial to, and on the outer side of, the artery, the medial popliteal nerve being superficial to, and on the outer side of, the vein. In the middle of the space the medial popliteal nerve is directly behind the artery, the popliteal vein intervening between them. In the lower part of the space the popliteal vein is behind and on the inner side of the artery, the medial popliteal nerve is behind and on the inner side of the vein, a relationship which is the reverse of that in the upper part of the space. Ihe genicular branch of the obturator nerve (when present) traverses the adductor magnus, usually above, but sometimes through the femoral opening, and descends behind and somewhat to the inner side of the popliteal artery; finally, the nerve leaves the main vessel and passes into the knee-joint from behind, traversing the posterior ligament in company with the middle genicular artery.



Fig. 336. — The Popliteal Space (Deep Dissection).

Branches.—The branches are muscular, cutaneous, and genicular.

The muscular branches may be subdivided into two sets, superioi and inferior. The superior are distributed to the lower parts of th( hamstring muscles, and anastomose with the lower perforating branche: of the profunda femoral artery. The inferior or sural supply th( gastrocnemius, the plantaris, and the soleus.

The cutaneous branches supply the skin covering the poplitea fossa, and the upper part of the back of the leg. The largest and most constant, sometimes called the sural cutaneous artery, is given of close to the lower angle of the fossa, descends in the groove marking the junction of the two heads of the gastrocnemius, and is there c companion of the short saphenous vein.

The genicular branches (Fig. 336) are five in number—two superior, lateral and medial; one middle; and two inferior, lateral and medial.

The lateral superior genicular artery courses outwards above the lateral condyle of the femur, lies deeply to the biceps femoris, and passes through the lateral intermuscular septum into the vastus intermedius muscle.

The medial superior genicular artery courses inwards above the medial condyle of the femur, lies deeply to the tendon of the adductor magnus, and enters the vastus medialis.

The middle genicular artery is sometimes an independent branch, but often arises in common with the lateral superior genicular branch. It passes forwards through the posterior ligament of the knee-joint, and supplies the synovial membrane and ligaments within the joint.

The lateral inferior genicular artery at first courses horizontally outwards, and then forwards above the head of the fibula; it lies deeply to the tendon of the biceps and the lateral ligament of the knee-joint.

The medial inferior genicular artery is distinguished by its comparatively large size and oblique course. It passes downwards and inwards to gain the inferior aspect of the medial condyle of the tibia, whence it passes forwards, lying deeply to the medial ligament of the knee-joint.

Anastomosis about the Knee-Joint (Fig. 337).—The two superior and two inferior genicular arteries are given off above and below the joint respectively. Clinging closely to the bone in each instance, they all gain the front of the limb, and take part in an anastomosis about the patella; the two superior arteries communicate with one another above this bone, the two inferior below it. The anastomoses between these arteries are both superficial and deep. The superficial anastomosis between the two superior arteries lies in front of the tendon of the quadriceps femoris, that between the two inferior in front of the ligamentum patellae. Small branches derived from these superficial anastomoses supply a fine network of vessels in front of the patella, ‘ the pre-patellar rete.'

r 6 , ^ ee P anas f° m osis between the two superior arteries is on the deep aspect of the tendon of the quadriceps extensor, while that between the two inferior lies deeply to the ligamentum patellae.

In addition, there are vertical anastomoses, either on the lateral aspects of the joint or close to the margins of the patella, whereby the two lateral genicular arteries on the one hand, and two medial on the other, communicate with each other. These extensive anastomoses between the articular arteries are supplemented by other arteries. The musculo-articular branch of the descending genicular (femoral) descends from above the joint, and joins the anastomosis above the patella; the descending branch of this artery joins the vertical anastomosis on the inner aspect of the knee. The descending branch of the lateral femoral circumflex usually ends by communicating with the lateral superior genicular. The anterior tibial recurrent artery ascends from below, and joins the anastomosis below the patella; on the back of the joint the posterior tibial recurrent artery joins the two inferior genicular arteries.


Fig. 337 —The Anastomosis about the Knee-Joint as viewed from in Front.

Varieties of Popliteal Artery .—The vessel may divide into the anterior and )osterior tibial arteries at the upper border of the popliteus muscle.

The terminal branches may be three in number, the additional branch being he peroneal artery.

In very rare cases the popliteal artery divides high up into two trunks of

qual size; the two re-unite prior to the normal termination of the vessel. The popliteal vein commences at the lower border of the popliteus nuscle, where it results from the junction of the venae comites of the anterior and posterior tibial arteries. It terminates at the femor opening in the adductor magnus, where it is continuous with tt femoral vein. Its tributaries correspond with the branches of tl popliteal artery, with, in addition, the short saphenous vein.

The medial popliteal (tibial) nerve (Fig. 336) is one of the termin branches of the sciatic; its fibres are derived from the fourth and fifl lumbar, the first, second, and third sacral nerves. It extends fro] the upper angle of the popliteal space to the lower border of the po] liteus muscle, where it is continuous with the posterior tibial nerve.

Branches. — The branches are genicular, cutaneous, and muscular

The genicular branches are two or three in number: a superu medial genicular branch (inconstant) accompanies the medial superb genicular artery; a middle genicular (azygos) is a companion of tl corresponding artery; a medial inferior genicular accompanies tl medial inferior genicular artery.

The sural nerve descends in the middle line of the calf, and, aft< traversing the deep fascia, is joined by the sural communicating nen from the lateral popliteal.

The muscular (sural) branches are usually five in number: one 1 the outer head of the gastrocnemius, one to the plantaris (often comir off in common with the preceding), one to the inner head of the gastroi nemius, one to the soleus which descends between the outer hea of the gastrocnemius and plantaris, and one to the popliteus. Tl nerve to the popliteus is deeply placed, and lies in close contact wit the muscle to the outer side of the popliteal vessels. It winds roun the lower border of the popliteus, and, taking a recurrent course, ente: the deep surface of the muscle. In addition to supplying the popliteu it furnishes the following branches: articular to the superior tibi< fibular joint; vascular to the anterior and posterior tibial arteries; an interosseous, a long slender branch which, given off from the nerve c it winds round the lower border of the popliteus muscle, descends c the interosseous membrane, supplies a nutrient twig to the tibia, an ends in the inferior tibio-fibular joint.

The lateral popliteal (common peroneal) nerve (Fig. 336) is tl other terminal branch of the sciatic; its fibres are derived from tl fourth and fifth lumbar, and the first and second sacral nerves. ! commences at the upper angle of the popliteal space, and, descendir obliquely downwards and outwards, follows the tendon of the bicep It crosses the outer head of the gastrocnemius, and eventually, windir round the neck of the fibula under cover of the peroneus longus muscl gains the front of the limb, where it ends by dividing into the anterk tibial and musculo-cutaneous nerves.

Branches. — The branches are genicular, cutaneous, and termina

The genicular branches are three in number: a superior lateral gen cular' branch accompanies the lateral superior genicular artery; a inferior lateral genicular branch accompanies the lateral inferior genicuk artery; and a recurrent genicular , which, given off close to its terminatioi accompanies the anterior tibial recurrent artery.


The cutaneous branches are two in number: the lateral cutaneous lerve of calf, given off at a higher level, supplies the skin on the outer ide of the calf, and may descend as low as the lateral malleolus; the ural communicating nerve, given off at a lower level, varies very much n size, and, passing downwards and inwards over the outer head of he gastrocnemius, supplies branches to the skin of the calf, and, after raversing the deep fascia, joins the sural nerve.

The terminal branches are the anterior tibial (q.v.) and the musculomtaneous (q.v.).

The popliteal lymphatic glands, usually four in number, lie in close )roximity to the popliteal artery, one being superficial to the vessel, me deeply to it, and the others being disposed one on either side of it. rhey receive afferent lymphatics from the following sources: the sole >f the foot; the deep parts of the back of the leg; superficial lymphatics ic.companying the short saphenous vein, and draining the outer side )f the foot and the outer side and back of the leg; and two efferent ymphatics from the anterior tibial lymphatic gland, which lies on the ront of the upper part of the interosseous membrane.

The efferent lymphatics of the popliteal glands accompany the nain bloodvessels and end in the deep inguinal glands.

Front and Inner Side of the Thigh.

Landmarks — Thigh .—The anterior superior spine of the ilium is

situated at the anterior extremity of the iliac crest, and can readily oe felt. It is the point from which the length measurement of the lower limb is usually taken. The inguinal (Poupart’s) ligament extends between the anterior superior iliac spine and the pubic tubercle. When the thigh is extended, abducted, and rotated outwards, it can De felt as a tense and somewhat curved band. Immediately below it the inguinal lymphatic glands may sometimes be felt. The inner end

>f the inguinal ligament marks the position of the pubic tubercle, which Is situated at the lower and inner part of the anterior abdominal wall about 11 inches lateral to the upper limit of the symphysis pubis. If, is is sometimes the case, it is a sharp-pointed process, it can readily be felt beneath the skin. In most bodies, however, it is a more or less indistinct tubercle, and, especially in corpulent bodies, cannot be felt. In such cases the skin of the scrotum may be invaginated with the Inger, whereby the fatty tissue is displaced from over the tubercle. If the pubic tubercle cannot be distinguished by this method, the thigh should be well abducted to render the adductor longus muscle prominent; the upper limit of the tendon of this muscle serves as a ?uide to its position, as it lies above and to its outer side. Ihe pubic tubercle is the guide to the following openings: the superficial inguinal ring lies immediately above and to its outer side; the femoral ring is situated fully i inch lateral to the spine; situated on a line drawn horizontally outwards from the spine across the front of the thigh is the saphenous opening, which is below and slightly lateral to it.


The pubic crest extends inwards from the pubic spine for a distanc of about i inch, and ends in the pubic angle. The crest may be fe in the male if the skin of the back wall of the scrotum is invaginatec and the little finger passed into the superficial abdominal ring, of whic the crest forms the lower limit. The spermatic cord may be fe descending over the pubic crest, and sometimes lies in front of tf pubic tubercle. The pubic angle cannot usually be felt. The ischi< pubic ramus can be felt as a bony ridge extending from the ischi; tuberosity to the lower part of the symphysis pubis. The saphenoi opening is situated below and lateral to the pubic tubercle, and extenc downwards for about i| inches below the inner part of the inguin; ligament. At the lower extremity of the opening the superficial sul inguinal lymphatic glands may sometimes be felt. One inch belo 1 the inguinal ligament, and a little to the outer side of its mid-poin the head of the femur may be felt.

The greater trochanter is situated about 4 inches below the anteric superior iliac spine, and about 4 inches behind a line let fall vertical! from it. Its outline is more or less obscured by the muscles whic cover it, but the following guides may serve to localize it:

Holden’s Guide. —In the recumbent position the top of the greate trochanter is very nearly at the same level as the pubic tubercle.

Nelaton’s Line. —This is a line drawn by stretching a tape froi the anterior superior iliac spine to the most prominent part of th ischial tuberosity. It passes over the top of the greater trochanter, an crosses the centre of the acetabulum.

Bryant’s triangle is constructed as follows: A line is drawn horizontally bad wards from the anterior superior iliac spine and another vertically upwarc from the top of the greater trochanter. These two lines are the sides of a triang' of which the base is a line drawn from the anterior superior iliac spine to th top of the greater trochanter. The base line is used for estimating shortei ing of the neck of the femur. Should it be shorter than the correspondin line on the opposite side of the body, shortening of the femoral neck is ii dicated.

The centre of the acetabulum is at the same horizontal level as th top of the greater trochanter.

The position of the femoral (Scarpa’s) triangle is indicated by a sligh depression below the inguinal ligament. If the limb is forcibly at ducted, the outline of the adductor longus on the inner side of th thigh is made prominent, and its narrow rounded tendon of origin i readily felt at a point on the body of the pubis below and medial t< the pubic tubercle. The rectus femoris is responsible for an elongate* vertical prominence on the front of the thigh. The well-marke< prominence over the lower fourth of the thigh on its inner aspect i caused by the vastus medialis muscle. When the knee is flexed, th narrow round tendon of the adductor magnus can be felt as it descends posterior to the vastus medialis, to reach the adductor tubercle on th upper aspect of the medial condyle of the femur.

Knee ,—The outline of the patella and the ligamentum patellae passing from the lower pointed end of the patella to the tubercle of he tibia, can be easily identified.

The medial condyle of the femur is a large prominence projecting nwards. On its inner surface the blunt medial epicondyle is easily elt. When the knee-joint is flexed, the adductor tubercle, with the larrow round tendon of the adductor magnus inserted into it, can be elt at the upper and back part of the medial condyle. The upper border of the patellar surface of the femur may be felt when the kneeoint is flexed, but it is somewhat obscured by the tendon of the quadiceps femoris. It is obliquely disposed, being at a higher level laterally Tan medially. The adductor tubercle is on the same level as the )uter part of the upper border of the patellar surface. A line conlecting these two points indicates the line of junction of the lower epiphysis of the femur with the shaft, the junction occurring at the

wentieth year. The lateral condyle of the femur is much less prominent than the medial. Below the lateral femoral condyle the .ateral epicondyle of the tibia is a marked prominence at the outer ind anterior part of the knee-joint, and presents a ridge to which the ilio-tibial tract of the fascia lata is attached. The head of the fibula is easily felt below and behind the lateral condyle of the tibia. The tubercle of the tibia can be felt at the upper end of the sharp anterior border or crest of the bone. Its upper border is on the same level as the upper part of the head of the fibula. It is to be noted that the medial condyle of the tibia has a slight inclination backwards as well as inwards.

The lower limit of the synovial membrane of the knee-joint corresponds with the level of the ridge on the anterior and outer part of the lateral condyle of the tibia; this ridge serves for the attachment of the ilio-tibial tract of the fascia lata. If this ridge cannot be identified, a transverse line just above the head of the fibula indicates the lower limit of the membrane. The synovial membrane clothes the upper half of the posterior surface of the ligamentum patellae. Behind the lower end of this ligament a bursa intervenes between it and the upper smooth part of the tubercle of the tibia. Superiorly the synovial membrane extends upwards above the patella in the form of a large pouch upon the front of the femur for about 2 inches above the upper border of the patellar surface of the bone. This pouch lies deeply to the tendon of the quadriceps femoris, and communicates with a bursa situated immediately above it, this bursa extending upwards for about another inch.

In extension of the knee-joint the patella is situated above the level of the condyles of the femur. In flexion it lies over the intercondylar notch. In extreme flexion the patella articulates chiefly with the semilunar impression on the outer part of the tibial surface of the medial condyle of the femur, close to the intercondylar notch. The particular part of the patella which thus articulates is the inner vertical zone on its posterior surface immediately adjoining the medial border. In flexion of the joint there is a depression on either side of the ligamentum patellae, and also on either side of the patella itself, the latter depressk being deeper on the inner than on the outer side. In this position the joint the anterior margin of each tibial condyle is readily felt, ar above each is a hollow which separates it from the correspondii femoral condyle. In extension of the joint the depression on eith side of the patella is also manifest, being, as in flexion, deeper on i inner side. The depression on either side of the ligamentum patell; however, is not present, this being due to the lateral dispersion of tl fat, which is under cover of the ligamentum patellae in extension.

The superficial fascia is, for about 3 inches below the inguinal lig ment, artificially divisible into two layers—subcutaneous and dee The subcutaneous layer is fatty, and, when traced upwards, is coi tinuous with the superficial fascia on the anterior abdominal wa^ The deep layer is a very delicate membrane, best seen on the inrn side of and deep to the long saphenous vein, this vessel lying betwee it and the subcutaneous layer. When traced upwards, it is found 1 blend with the fascia lata a short distance below the inguinal ligamen

The prepatellar subcutaneous bursa is a large bursa in the sul cutaneous tissue covering the front of the patella.

Cutaneous Nerves (Fig. 338)— The Femoral Branch of the Genitt femoral Nerve. —The genito-femoral nerve is a branch of the lumbc plexus, its fibres being derived from the first and second lumbar nerve Its femoral branch passes downwards to the thigh, behind the inguin; ligament, superficial to the femoral artery, and embedded in the femon sheath. It supplies a twig to the artery, and, traversing the femon sheath and the fascia lata, is distributed to the skin covering tb femoral triangle.

The ilio-inguinal nerve is a branch of the lumbar plexus, its fibre being derived from the first lumbar nerve. It escapes from the inguinc canal through the superficial inguinal ring, where it lies directly t the outer side of the spermatic cord or round ligament of the uterus according to the sex. Having traversed the intercolumnar fascia, i descends, and is distributed to the skin on the upper part of the inne side of the thigh, and to the adjacent skin of the scrotum in the mal and of the labium majus in the female.

The lateral cutaneous nerve of thigh is a branch of the lumbar plexus being derived from the second and third lumbar nerves. It descend into the thigh behind the outer end of the inguinal ligament, and divide into two branches, a small posterior and a large anterior. The posterio branch is distributed to the skin of the upper part of the outer side 0 the thigh, and also to the skin of the outer and lower part of the glutea region. The anterior branch traverses the fascia lata at a lower level and supplies the skin on the outer side of the thigh, extending downwards as low as the knee. It occasionally sends a twig to the patella: plexus.

The position of the lateral cutaneous nerve as it passes into the thigh is ver) inconstant. It may be close to the anterior superior iliac spine or at a variable distance to its inner side.


The intermediate cutaneous nerve is represented by two or three branches of the femoral nerve, which pierce the fascia lata about 4 inches below the inguinal ligament. One and sometimes two branches pass through the upper part of the sartorius. They supply the skin of the front of the thigh in the lower two-thirds, extend downwards t the knee, and end by taking part in the formation of the patella plexus.


Fig. 338. — The Subcutaneous Vessels, Nerves, and Lymphatic Glands on the Front of the Thigh.


Fig. 339. — Muscles and Cutaneous Nerves of the Lower Limb (Anterior Aspect).


d he medial cutaneous nerve is also a branch of the anterior femoral It crosses the femoral artery superficially, and from without inwards near the apex of the femoral triangle. It usually divides into two branches, anterior and posterior. The two branches descend on the ler side of the thigh deep to the fascia lata, and correspond in position the long saphenous vein. At the junction of the middle and lower irds of the thigh the anterior branch traverses the fascia lata, and, scending to the inner side of the knee-joint, supplies the skin of the ler side of the thigh in its lower third. It finally passes outwards to the patella, and ends in the patellar plexus. The posterior branch lows the posterior border of the sartorius, and traverses the fascia

a at the level of the medial condyle of the femur. It descends on the inner side of the knee, lies behind the long saphenous nerve, and pplies the skin of the inner side of the leg. The medial cutaneous rve gives off two or three cutaneous branches in the femoral triangle, lese branches cross the femoral artery superficially, and are disputed to the skin of the inner side of the thigh in its middle third, le posterior branch of the nerve gives a branch to the subsartorial exus.

The saphenous nerve (Fig. 349) is a branch of the femoral nerve. l the lower part of the femoral triangle it lies close to the outer side

the femoral artery, and thence descends into the subsartorial lunter’s) canal with the artery, which it crosses superficially and from ithout inwards. It escapes from the lower end of the subsartorial mal by traversing its roof in company with the saphenous branch of Le descending genicular artery, with which it descends at the hinder Ige of the sartorius to the inner side of the knee. From the knee it isses downwards to the inner side of the leg, and divides into two ranches, which accompany the long saphenous vein, the larger branch ing behind the vein and the smaller in front. At the ankle the larger ranch passes downwards in front of the medial malleolus, and gains le inner side of the foot, along which it courses as far as the metatarsolalangeal joint of the great toe. In the subsartorial canal the saphe3us nerve gives a branch to the subsartorial plexus. In the lower irt of the thigh it gives off an infrapatellar branch, which traverses the irtorius, supplies the skin on the front of the knee, and ends by joining

ie patellar plexus. Below the knee-joint the nerve distributes branches to the skin f the inner side of the leg and of the inner side of the foot. In the pper part of the leg it communicates with the posterior branch of ie medial cutaneous nerve, and on the inner side of the foot with the Lusculo-cutaneous.

Obturator Nerve. —The anterior division of the obturator nerve sually furnishes a branch, which, becoming superficial about the liddle of the thigh, between the posterior border of the sartorius and ie anterior border of the gracilis, is distributed to the skin on the mer aspect of the thigh for a variable extent.

The patellar plexus (Fig. 338) is a network of fine nerves on the ont of the patella. The nerves which contribute branches to it are tie infrapatellar branch of the saphenous; branches of the intermediate utaneous; the anterior branch of the medial cutaneous; and occasionally the lateral cutaneous. Branches from the patellar plexus pas; downwards, and supply the skin below the patella.

The subsartorial plexus (Fig. 349) is situated about the middle thin of the thigh, and lies deeply to the sartorius as this muscle forms th< roof of the subsartorial canal. The nerves contributing branches t< it are the saphenous; the posterior division of the medial cutaneous and the superficial or anterior division of the obturator. The branche of the plexus are distributed to the skin on the inner side of the thigl for a variable distance.

The branches of the subsartorial plexus distributed to the skin are mainh derived from the obturator nerve. These branches may extend downward below the knee, and supply the skin on the inner aspect of the leg.

Lymphatic Glands. —The largest, the most important, and the mos numerous lymphatic glands of the lower limb occupy the upper end o the front of the thigh, and are known as the inguinal glands. The} are arranged in two groups, superficial and deep. The superficia glands are embedded in the superficial fascia; the deep are disposec about the femoral vessels, and are therefore situated deeply to th( plane of the deep fascia.

The superficial inguinal glands (Fig. 338) vary in number fron twelve to twenty. They are arranged in two sets. A lateral set sometimes known as the superficial inguinal glands proper , are paralle' to and slightly below the inguinal ligament. The lowest or mosl medial of these glands are disposed about the superficial external pudendal artery, and are known as the pubic glands. The lower set, The superficial subinguinal glands, are found in the region of the cribriform fascia and on either side of the upper end of the long saphenous vein. The largest and most constant of these glands occupies the angle of junction between the anterior femoral cutaneous vein and the long saphenous vein.

The afferent vessels to the superficial inguinal glands are the superficial lymphatics draining the greater part of the lower limb, the anterior abdominal wall below the level of the umbilicus, the gluteal region, the perineum and the anus, the scrotum and penis in the male, the labium majus and prepuce of the clitoris in the female. The chief superficial lymphatics of the lower limb follow the long saphenous vein. They receive tributaries draining the outer part oi the foot, the front and inner side of the leg, and the front and back of the thigh. They join the subinguinal glands. Some of the superficial lymphatics draining the outer side of the thigh join the upper lateral group of superficial inguinal. The superficial lymphatics of the buttock wind round the outer side of the hip, and join the upper glands of the lateral group. The superficial lymphatics draining the anterior abdominal wall course downwnrds to the lateral group of superficial inguinal; many of them follow the superficial epigastric vessels. The superficial lymphatics of the genital organs, the perineum, and the anus mostly join the medial group of superficial inguinal glands.

The efferent vessels converge to the saphenous opening, where they traverse the cribriform fascia. Some of them join the deep inguinal glands, others pass upwards through the femoral canal and join the external iliac glands.


The deep inguinal glands, much less umerous than the superficial, are two or tiree in number. They lie to the inner ide of the upper end of the femoral vein. )ne of them (Cloquet’s gland) usually ccupies the femoral canal.

Their afferent vessels drain the deep parts of he lower limbs, the deep lymphatics of which ccompany the main arteries. They are also Dined by the lymphatics of the glans penis in he male and of the clitoris in the female, and eceive some of the efferent vessels of the uperficial inguinal glands.

The efferent vessels pass upwards hrough the femoral canal and join the xternal iliac glands.

The long saphenous vein (Fig. 340) .rises from the inner end of the venous irch on the dorsum of the foot. It passes ipwards in front of the medial malleolus ind on the inner side of the leg, where it ies about a finger’s breadth behind the nedial border of the tibia. From the leg t passes to the inner side of the knee, vhere it lies behind the most prominent iart of the medial condyle of the femur. Mom the knee it ascends to the inner side )f the thigh, following the hinder edge )f the sartorius more or less closely. [Wards the upper end of the thigh it nclines to the front of the limb, and at a x>int about 1^ inches below the inguinal igament it passes backwards, traverses the cribriform fascia occupying the sapheious opening and the anterior wall of the Amoral sheath; it finally ends by joining the femoral vein. The vein is contained in the superficial fascia for its whole extent, and receives many tributaries from the front and inner side of the leg md from the thigh; it has numerous communications with the deep veins of the leg. Two large tributaries joining its upper end are fairly constant. One, the 'interior femoral cutaneous , collects the blood from the front of the thigh; the uther, the posterior femoral cutaneous, brains the inner and back parts of the thigh.



Fig. 340.— The Long Saphenous Vein and its Tributaries.

The anterior femoral cutaneous vein is of particular importance, as it cross the apex of the femoral triangle, where it lies directly in front of the femor artery, and is liable to be cut when this vessel is exposed.

As it traverses the cribriform fascia the long saphenous vein receiv( the superficial circumflex iliac, the superficial epigastric, and the supe ficia.1 external pudendal veins; these three superficial veins often joi together to form a common trunk. The long saphenous vein is sai to have about fifteen valves, but in most cases they are much le< numerous. One valve is found in the vein just before it traverses th cribriform fascia, and another at its opening into the femoral vein.

The vein is occasionally double in the femoral part of its course. This due to the vein dividing into two trunks shortly after it enters the thigh. Tt two ascend close together and unite to form one trunk close to the saphenoi opening.

The deep fascia or fascia lata is a dense fibrous membrane ensheatt ing the muscles of the thigh like a stocking. Above it is attached behind to the sacrum and coccyx; laterally to the outer lip of the ilia crest, and between them is continuous with the lumbar fascia; in fron to the inguinal ligament and the pubic crest; and medially to the bod 1 of the pubis, the ischio-pubic ramus, the ischial tuberosity, and th sacro-tuberous ligament. Below it is attached, on the outer side of th knee, to the head of the fibula and lateral condyle of the tibia; in fron to the lateral borders of the patella, and here takes part in forming the lateral patellar ligaments; it clothes the front of the patella, anc between it and the bone is a subfascial prepatellar bursa; behind i helps to form the roof of the popliteal fossa, being continuous belov this space with the deep fascia investing the calf; on the inner side o the knee it is attached to the medial condyle of the tibia.

Some of the fibres of the fascia lata have a circular disposition, other* are directed longitudinally. It is interrupted by a large number o: minute holes giving passage to bloodvessels and nerves. The fascia if stronger and thicker on the outer side of the thigh, where it give* attachment to a large part of the gluteus maximus and to the tensoi fasciae latae. It is also strong on the front of the knee on either side of the patella, where it blends with tendinous expansions from the quadriceps femoris muscle to form the lateral patellar ligaments.

A band-like thickening on the outer side of the thigh, extending between the tuberosity of the iliac crest above and the lateral tibia] condyle and the head of the fibula below, is known as the ilio-tibial tract. At the attachment of the tensor fasciae latae, it is continuous with a deep fascial layer, which passes upwards on the deep surface of the muscle, and is attached above to the floor of a groove on the gluteal surface of ilium immediately above the margin of the acetabulum. To this groove the reflected head of the rectus femoris muscle is attached. This deep fascial layer is intimately connected with the capsular ligament of the hip-joint and the tendon of the gluteus minimus.


Cribriform Fascia. —On the front of the upper part of the thigh, a ittle way below the inner part of the inguinal ligament, is a somevhat oval area, where the character of the fascia lata is profoundly nodified. Instead of being dense and membranous it is loose and atty, presenting the characteristics of the superficial fascia rather han those of the deep. Further, it is interrupted by numerous holes >r passages for the transmission of vessels, and on this account is known is the cribriform fascia. The vessels traversing the cribriform fascia ire the long saphenous vein, the superficial branches of the femoral irtery with the exception of the superficial circumflex iliac, which lsually passes through the fascia lata above and to its outer side, the /eins accompanying these arteries, and the efferent vessels of the supericial inguinal glands.

The cribriform fascia being relatively loose and non-resistant, the vessels

raversing it are not pressed up, and the flow of fluid through them hindered )r stopped, as would be the case were the fascia lata in this situation dense and ■esistant. This resistance is increased when the fascia lata is put on the stretch Dy the contraction of the thigh muscles.

Saphenous Opening (Fig. 341).—If the cribriform fascia be removed, 1 deficiency or opening in the fascia lata, the saphenous opening, ls artificially defined and the femoral sheath containing the femoral vessels is exposed. The opening is oval in outline, and although the upper,

Duter, and lower margins are well defined, the inner margin is indistinct. The part Df the fascia lata lying to the outer side of the saphenous opening is known as the iliac portion, while that on the inner side is distinguished as the pubic portion. The iliac portion is attached above to the whole length of the inguinal ligament, and at the outer limit of the saphenous opening has a well-defined free edge, the falciform border. The falciform border arches upwards and inwards to the pubic tubercle as the superior cornu, which forms the upper margin of the opening, while its lower end is continuous with a crescentic edge, the inferior cornu, which forms the lower limit of the opening, occupies the angle of junction between the long saphenous vein and the femoral vein, and merges medially with the pubic portion. The pubic portion is continuous with the iliac portion below the saphenous opening, but when traced upwards is found to cling to the pectineus muscle, and with that muscle lies deeply to the femoral sheath containing the femoral vessels. Above it is attached to the pectineal line, which marks the upper limit of the origin of t" pectineus.


Fig. 341. — Diagram to show Formation of Saphenous Opening.

IF, medial part of inguinal ligament; E, external inguinal ring; P, fascia over pectineus; F, falciform edge; SV, saphenous vein opening into femoral vein. Femoral sheath not shown.


From the foregoing description it will be realized that, although the ili and pubic portions of the fascia lata are continuous with one another, and c disposed in the same plane below the saphenous opening, yet when trac upwards they occupy different planes. The iliac portion as it arches inwar above the saphenous opening lies in front of the femoral sheath containing t femoral vessels, while the pubic portion clinging to the pectineus lies behind t femoral sheath.

Intermuscular Septa (Fig. 342). — Adherent to or continuous wi the deep surface of the fascia lata ensheathing the thigh are thr


Fig. 342 -— A Semidiagrammatic Section through the Middle of the Thigh illustrating the disposition of the three intermuscular sept;

the Boundaries and Contents of the Subsartorial Canal, and th Course and Distribution of a Perforating Artery.



intermuscular septa, which occupy the intervals between the chie muscle groups and are attached deeply to the linea aspera of th femur. The three septa, together with the fascia lata, form the wall of three compartments containing the three muscle groups of the thigh the extensors, the adductors, and the flexors respectively. A later & septum, strong and well marked, intervenes between the extensor and flexors. A medial septum, relatively weak, separates the extensor from the adductors. A posterior or postero-medial, the weakest an< least distinct of the three, lies between the adductors and flexors.

It is convenient to remember that the three muscle groups occupying th three fascial compartments of the thigh have independent nerve-supplies, the extensors being supplied by the femoral, the adductors by the obturator, and le flexors by the sciatic.

The Femoral (Scarpa’s) Triangle. —When the fascia lata is removed rom the front of the upper part of the thigh, a space known as the amoral triangle is exposed. This space is of great surgical importance, s the main vessels of the limb contained therein are very superficially isposed, and are easily approached from the surface.

Boundaries of the Femoral Triangle. —The base of the triangle is bove, and is formed by the inguinal ligament. Of the two sides of he triangle, the lateral one is formed by the medial edge of the sarorius. This muscle crosses the front of the thigh obliquely as it passes rom the anterior superior iliac spine, above and to the outer side, to he inner aspect of the thigh below. The medial side is formed by the dge of the adductor longus. This muscle is attached above to the >ubis close to the extremity of the inguinal ligament, inclines obliquely lownwards and laterally, and finally disappears under cover of the artorius. The lower limit, or apex of the space, is the point where he sartorius, lying superficially, crosses the more deeply placed lateral dge of the adductor longus.

Floor of the Femoral Triangle. —The lateral part of the floor is occu)ied by the ilio-psoas, which results from the fusion of the iliacus and >soas muscles; a groove indicates the junction of the broader muscular liacus with the narrower more tendinous psoas lying to its medial side, rhe medial part of the floor is formed by the pectineus muscle.

The femoral triangle, as originally defined by Scarpa, was the space bounded >n either side by the sartorius and the adductor longus muscles. The inner >oundary of the space has been variously interpreted by anatomists as the ‘ most )rojecting part of the adductor longus,' or ‘ its inner margin.’ The most proecting part of the adductor longus is very ill defined, especially in the dissected subject; if the inner margin of the muscle is adopted, it carries the space downvards into the thigh for some considerable distance, and thus serves no useful rnrpose; further, the level at which the inner margins of the sartorius and idductor longus meet is exceedingly variable. The outer margin of the adductor ongus has been adopted in this work as the inner boundary of the femoral triangle, is it more accurately delimits the space in which the main artery of the limb is superficially disposed on the front of the thigh. The adductor brevis muscle is sometimes stated to be one of the muscles in the floor of the triangle. It is true hat in an ill-developed subject the adjoining edges of the pectineus and adductor ongus are not in direct approximation, and the adductor brevis may be seen in she narrow interval between the two. As the adductor brevis, however, is on m altogether different and deeper plane to that of the other muscles forming the loor of the triangle, and does not come into direct relationship with any of its )ccupants, it has been omitted in the foregoing description.

Contents of the Triangle—The Femoral Vessels. —The femoral artery nay be said to bisect the triangle. It extends vertically downwards rom behind the mid-point of the inguinal ligament above to the apex )f the space below, where it disappears under cover of the sartorius. Several branches are given off from the artery, including the three superficial branches (Figs. 338, 343), and other branches which will be lescribed later. Immediately below the inguinal ligament the femoral vein lies to the inner side of and on the same plane as the artery, bu it inclines outwards and occupies a deeper plane towards the lower enc of the triangle, at the apex of which it lies behind the artery. Lym phatic Glands .—The deep inguinal glands, two or three in number, ar< disposed to the inner side of the femoral vein. They receive the deej lymphatic vessels of the limb coursing upwards with the femoral arten and efferent vessels from the superficial inguinal glands. Their efferen vessels, together with some of the efferent vessels from the superficial glands, pass upwards on the inner side of the femoral vein into th( abdominal cavity, where they join the external iliac glands. Tin nerves are three in number. Occupying the upper and outer angle r the lateral cutaneous nerve of thigh. This nerve passes into the thigl from behind the outer extremity of the inguinal ligament, where it lieJ to the inner side and below the anterior superior iliac spine; it is usuall) contained in the space for a very short distance only.



Fig. 343. — The Femoral (Scarpa's) Triangle and its Contents.

For the sake of simplicity the branches of the femoral nerve are not all indicated


The position of the lateral cutaneous nerve of thigh is very variable; it may bf found at any point between the anterior superior iliac spine laterally and tm femoral nerve medially.


The femoral is a large nerve which lies on the outer side of the moral artery, a small part of the psoas intervening between them, occupies the groove indicating the junction of the iliacus and psoas uscles, and a short distance below the inguinal ligament subdivides to a sheaf of branches. The femoral branch of the genito-femoral,


Fig. 344.— A Diagrammatic Section through the Femoral Canal and Lower Part of Abdominal Cavity, illustrating the Relations of the Femoral Canal and Femoral Ring.

The path of a femoral hernia is indicated by an arrow.

fter escaping into the thigh from behind the inguinal ligament, lies in 'ont of and somewhat to the outer side of the femoral artery.

The Femoral Sheath. —After removal of the fascia lata, the femoral essels in the upper part of the femoral triangle do not at once come ito view, as they are completely surrounded by a bag-like investment f fibrous tissue, the femoral sheath. The femoral sheath is prolonged upwards behind the inguinal ligament, and is continuous above w: the fascial lining of the abdominal cavity. Its anterior wall, lying front of the femoral vessels, is continuous with the fascia lining t deep aspect of the anterior abdominal wall or fascia transversalis, wh its posterior layer, which lies behind the femoral vessels, is continue with the fascia lining the posterior abdominal wall or fascia ilia (Fig. 344). The femoral sheath blends below with the connecti tissue walls of the femoral vessels, to which it is closely adherent.

Femoral Canal. —Extending between the front and back walls the sheath are two septa which subdivide it into three compartmen The outer or arterial compartment is occupied by the femoral artery; t middle or venous compartment by the femoral vein; the inner coi partment contains loose fatty connective tissue, may lodge one of t deep inguinal glands (Cloquet’s gland), and transmits the lympha vessels conveying lymph from the inguinal glands to the exterr iliac glands. It is essentially the lymphatic compartment, and known as the femoral (crural) canal.

The femoral canal is closed below by the blending of the femoi sheath with the walls of the femoral vessels; on its outer side is t' septum between it and the femoral vein, and on the inner side it limited by the continuity of the anterior and posterior walls of t' femoral sheath.

Femoral Ring .—The upper end or mouth of the femoral canal, the level where the sac of the femoral sheath opens out to becor continuous with the fascia lining the abdominal cavity, is known the femoral ring. It is somewhat oval in outline, is relatively larg in the male than the female, and has very important relations, front is the inguinal ligament, sometimes termed the superficial crur arch, deep to which are some transverse fibres adherent to and thicke ing the anterior wall of the femoral sheath, and known as the dec crural arch. In close proximity to the inguinal ligament is the infer! epigastric artery. Behind is the pubis covered by a comparative thin layer of the pectineus muscle. To the outer side is the upp end of the femoral vein, and on the inner side it is adherent to tl sharp resistant concave edge of the pectineal part of the inguinal lig ment, a deep, somewhat triangular reflection extending backwarc from the deep aspect of the inner extremity of the inguinal ligamei to the pectineal line.

Abnormal Obturator Artery (Fig. 345). —The obturator artery normal arises from the anterior division of the internal iliac. In about 30 per cen of cases, however, the obturator arises from the inferior epigastric artery ne; its commencement. This origin is more common in the female than in tl male, and is rarely bilateral. Such an abnormal obturator artery usually If close to the external iliac vein, and on the outer side of the femoral rir (F^g. 345, A). In rare cases the abnormal vessel crosses the femoral ring; : still rarer cases it follows the free edge of the pectineal part of the inguin ligament more or less closely; in such cases it lies on the inner side of the femor; ring (Fig. 345 , B and C). If a femoral hernia should occur under these lath circumstances, the aberrant obturator artery would lie upon the inner side < the neck of the sac, and it would thus be endangered in the operation for the relief of the strangulation. This, however, is a very rare position of an abnorma obturator artery, and is more frequent in the male than in the female; it i said to occur once in a hundred cases.



Fig. 345. — Diagrams of Abnormal Obturator Artery. (The red X indicates the position of the femoral ring.)

[A and B after Gray.] artery lateral to femoral ring; B, artery medial to ring, and close to base of the pectineal part of the inguinal ligament; C, artery medial to ring, and one or two lines from base of the pectineal part of the inguinal ligament.




An abnormal obturator artery arising from the inferior epigastric is due t< the suppression of the proximal part of the normal trunk, and its replacemen by a dilatation of the anastomosis between the pubic branches of the inferio epigastric artery and the obturator artery respectively.

Femoral Hernia (Fig. 344).—The femoral ring is to be regarded as a wea] spot in the abdominal wall through which one of the contents of the abdomina cavity, as, for instance, a loop of gut or a part of the great omentum, may pro trude downwards into the femoral canal, the resulting condition being knowi as a femoral hernia. As the hernia passes downwards it will necessarily b< contained in a pouch of the peritoneum continuous with that lining the abdomina cavity. Owing to the pressure from above, the peritoneal pouch will, as i sinks downwards into the femoral canal, push the soft contents of the cana (femoral septum) before it, the femoral septum becoming condensed and form ing a cover for it. The progress downwards of the hernia will be arrested a the lower limit of the femoral sheath— i.e., where its walls blend with the femora vessels. At this stage the hernia is said to be incomplete. As the lower limi of the femoral sheath is opposite the weak area of the fascia lata or cribriforn fascia, there is but little resistance in front, and the hernia may now bulg( forwards, stretching and pushing before it the anterior wall of the femora sheath, the cribriform fascia, the superficial fascia, and the skin. When this stage is reached the hernia is said to be complete. In order to open the peri toneal sac in which it is contained, and to expose the herniated viscus for the purpose of restoring it to the abdominal cavity, it would be necessary to incise the following layers or coverings of the hernia: (1) Skin; (2) subcutaneous tissue (3) cribriform fascia; (4) femoral sheath; (5) femoral septum; (6) peritoneum.

A femoral hernia may be constricted or strangulated, a circumstance whicl demands prompt relief. The strangulation usually occurs at the femoral ring : where the surrounding structures are comparatively unyielding. To relieve the condition the ring must be enlarged by means of a hernia knife. If the knife is directed forwards and upwards, the inferior epigastric artery may be severed if directed outwards, the femoral vein would be opened; a backward direction is contra-indicated, as the knife would come against hard unyielding bone. The knife is consequently directed inwards to sever the pectineal part of the inguinal ligament, and in so doing an abnormal obturator artery arising from the deef epigastric and coursing downwards to the inner side of the femoral ring might be wounded. Happily this is a very rare contingency.


The Front and Inner Side of the Thigh.

Sartorius (Fig. 346)— Origin .—The anterior superior iliac spine, and the upper part of the notch below it.

Insertion .—The upper end of the medial surface of the shaft ol the tibia. Its tendon broadens at its insertion, and is folded in such manner that its line of attachment is an inverted V, the anterior limb of which is considerably longer than the posterior. The two limbs embrace the insertions of the gracilis and semitendinosus.

Nery e-supply .—The femoral nerve. The nerve to the sartorius arises in common with the intermediate cutaneous nerve, and enters the muscle near the apex of the femoral triangle.

Action .'—Flexes the knee-joint, and rotates the leg inwards; flexes the hip-joint, abducts the thigh, and rotates it outwards. By flexing, abducting, and rotating the thigh outwards, and at the same time flexing the knee, it brings the lower limb into a position which is popuarly supposed to be habitually assumed by a tailor. Acting from the eg as its fixed point, it bends the trunk on the thigh and rotates it.

The sartorius is a long ribbon-like muscle, the fasciculi of which ire longer than those of any other muscle in the body. It can, therefore, bring about extensive movements, but with comparatively little

orce. Passing downwards and inwards from its origin, it crosses the jpper part of the front of the thigh obliquely, here forming the outer


Fig. 346.— The Muscles seen on the Front of the Thigh.


boundary of the femoral triangle. It then descends on the inner side of the thigh, where it helps to form the roof of the subsartorial canal. It is disposed on the inner side of the knee, where it is separated from the lateral ligament by a bursa. From the knee it passes downwards with an inclination forwards to its insertion (Fig. 350)- The upper part of the muscle is traversed by one or two of the branches of the intermediate cutaneous nerve, its lower part by the patellar branch of the long saphenous nerve.


Tensor Fascise Latse — Origin .—The outer aspect of the anterior superior iliac spine; the anterior end of the iliac crest for a short distance, and the bone immediately below it; some of its fibres are attached to the deep aspect of the fascia lata covering it.

Insertion .—The ilio-tibial tract of the fascia lata.


Fig. 347.— The Structures passing downwards into the Thigh behind the Inguinal Ligament. ,

Seen in section to illustrate the relations of the crural ring.


Nerve-supply .—The lower division of the superior gluteal nerve, the terminal branch of which enters the deep surface of the muscle.

Action .—Abducts and rotates the thigh inwards; helps to flex the hip-joint; and extends the knee-joint. In the latter movement the muscle acts in conjunction with the gluteus maximus, the ilio-tibial tract playing the part of a tendon common to the two muscles. The more important effect on the knee-joint is to maintain it in the extended position in the erect posture.


The tensor fasciae latae is a flat, strap-like muscle, the direction of which is downwards, with a slight inclination outwards and backwards.

Ilio-Psoas (Fig. 348).—The femoral portion of this muscle is described here. A fuller description of the psoas major and iliacus will be found in the section on the abdomen.

The outer portion of the muscle is fleshy, and represents the iliacus; the inner portion is chiefly tendinous, and represents the psoas. The tendon of the psoas is inserted into the lesser trochanter of the femur; the fibres of the iliacus are attached obliquely on the side of the tendon of the psoas; the lowest fibres extend downwards, and are attached to the shaft of the femur for some little distance below the lesser trochanter. Lying in the groove marking the distinction between the two muscles is the femoral nerve; the femoral artery and vein, surrounded by the femoral sheath, lie in front of the psoas. The ilio-psoas covers the front of the hip-joint, where a bursa intervenes between the tendon of the psoas and the capsular ligament.


Fig. 348.—The Psoas, Iliacus, and Quadratus Lumborum Muscles.


Pectineus — Origin .—A linear tendinous attachment to the pubic part of the ilio-pubic line, and a small area of muscular attachment in front of the inner extremity of the ilio-pubic line; upper or pectineal surface of the superior pubic ramus; the fascia lata covering the muscle.

Insertion .—The line which extends downwards from the back of the lesser trochanter of the femur to the linea aspera.

Nerve-supply .—The femoral nerve, a branch of which passes inwards behind the femoral sheath and enters the superficial surface of the muscle close to its outer border. The pectineus occasionally receives an additional supply from the anterior division of the obturator, the branch of which (when present) enters the deep surface of the muscle.

The pectineus belongs to the extensor group of muscles, but a part of it may be derived from the adductor musculature.

Action .—Flexes the hip-joint, adducts the thigh, and rotates it outwards.

The pectineus is a flat quadrilateral muscle directed downwards, outwards, and backwards. The surfaces at first look forwards and backwards, but towards its insertion the muscle undergoes a slight twist, and its two surfaces are then directed outwards and inwards. On the deep aspect of the muscle are the capsular ligament of the hip-joint, the anterior division of the obturator nerve, the obturator externus, and adductor brevis muscles.

The quadriceps femoris consists of four parts : the rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis. The rectus femoris, the most superficial part of the muscle, arises from the hipbone; the other three muscles take origin from the femur. The vastus intermedius is situated between, and is overlapped on either side by the vastus lateralis and vastus medialis.

1. Rectus Femoris — Origin .—By two strong tendinous heads. The straight head arises from the anterior inferior iliac spine. The reflected head arises from a groove on the gluteal surface of ilium immediately above the margin of the acetabulum, where it lies deeply to the gluteus minimus. The two heads unite at an angle of about 60 degrees.

When the lower limb is at right angles to the trunk, the habitual position of the limb in pronograde animals, the so-called reflected head is in line with the rest of the muscle. The reflected head is the sole origin in such animals, and is consequently known as the primary, head. The straight head is, phylogenetically, a recent acquirement, a necessity for this attachment of the muscle having arisen owing to the erect attitude and the habitual complete extension of the lower limb on the trunk; it is therefore known as the secondary or acquired head.

The muscle fibres are very short, have a penniform arrangement, and spring from either side of a superficially and centrally disposed tendon which occupies the upper part of the muscle. The fibres diverge from this tendon and are attached to a deeply-placed tendon of insertion, which spreads out and clothes the deep aspect of the muscle for some considerable distance.

2. Vastus Lateralis — Origin. —The upper part of the trochanteric line of the femur; the anterior and inferior borders of the greater tro


chanter; the outer side of the gluteal tuberosity; the outer lip of the linea aspera in its upper half; the adjacent portion of the shaft of the femur; and the upper part of the lateral intermuscular septum.

The vastus lateralis is tendinous at its origin, and an aponeurosis spreads downwards upon the superficial surface of the muscle for a considerable distance. The fibres are directed downwards and inwards. The anterior border has a free edge.

3. Vastus Intermedius (Crureus) — Origin .—The lower two-thirds of the upper or anterior part of the trochanteric line; the upper threefourths of the anterior and lateral surfaces of the shaft of the femur; the lower part of the outer lip of the linea aspera; the upper two-thirds of the lateral supracondylar line, and the bone immediately adjacent to it; and the lateral intermuscular septum.

The direction of the fibres of the vastus intermedius is chiefly downwards, but those of the lower and outer part of the muscle incline obliquely downwards and forwards. A broad aponeurotic sheet to which the muscle fibres are attached clothes the superficial or anterior aspect of the muscle. This aponeurosis narrows below and blends with the deep aspect of the tendon of the rectus.

The articularis genu (subcrureus) is a deep delamination of the lower part of the vastus intermedius. It usually arises in two bundles from the front of the shaft of the femur about 4 inches above the patellar surface. It is attached below to the large bursa which underlies the tendon of the quadriceps femoris, and which is continuous below with an upward prolongation of the synovial membrane of the knee-joint.

4. Vastus Medialis — Origin .—The posterior or lower part of the trochanteric line of the femur extending from the inferior cervical tubercle to the linea aspera; the inner lip of the linea aspera; and the medial intermuscular septum, by means of which it is adherent to the adductor longus and the tendon of insertion of the adductor magnus.

The general direction of the fibres of the muscle is downwards and outwards. The lower fibres of the muscle are much more horizontal and descend to a lower level than those of the vastus lateralis, which are more vertically disposed. The lower edge of the vastus medialis is opposite the middle of the patella.

At their attachments to the back of the shaft of the femur the vastus lateralis and the vastus intermedius are confluent with each other, but laterally and in front there is a connective tissue interval between the two, the vastus lateralis presenting a free edge on the front of the limb. The vastus medialis, on the other hand, has no free edge, and on the front of the limb cannot be separated from the vastus intermedius without rupturing muscle fibres; deeply, however, the attachments of the two muscles to the bone are separated from each other by the whole extent of the inner aspect of the shaft of the femur, which is free from muscular attachment and is sometimes termed the great bare area of the femur.

Insertion of the Quadriceps Femoris .—In the lower part of the thigh the tendon of the rectus femoris fuses with that of the vastus intermedius to form a common or suprapatellar tendon, which is implanted on the upper edge of the patella. The superficial fibres of the common tendon are prolonged downwards in the form of an expansion which clothes the front of the patella and blends below with the ligamentum patellae.

It may be noted that the effective insertion of the quadriceps femoris is the tubercle of the tibia to which the ligamentum patellae is attached. The patella is a sesamoid bone developed in the common tendon, and the ligamentum patellae, which functionally and morphologically is the part of the tendon distal to the patella, might conveniently be termed the infrapatellar tendon.

Situated deeply to the common tendon, between it and the front of the lower part of the shaft of the femur, is a large suprapatellar bursa which is continuous below with an upward prolongation of the synovial membrane of the knee-joint. In some cases the bursa is independent. This is frequently the case in young subjects, and represents the persistence of an early condition.

The muscle fibres of the vastus lateralis end in an aponeurosis which clothes the deep aspect of the muscle, blends with the outer side of the suprapatellar tendon, and sends an expansion downwards on the outer side of the patella. Most of the fibres of the vastus medialis also end in an aponeurosis which clothes the deep aspect of the muscle, and which blends with the inner side of the suprapatellar tendon. The lowest fibres, however, are attached directly to the upper half of the inner margin of the patella. From the lower edge of the muscle a tendinous expansion passes downwards on the inner side of the patella.

The ligamentum patellae is a thick broad band attached above to the blunt apex and adjacent margins of the lower part of the patella, and below to a rough area occupying the lower part of the tubercle of the tibia. A bursa intervenes between the ligament and the upper smooth part of the tubercle.

Nerve-supply .—The four parts of the muscle are supplied by independent branches from the femoral nerve. The nerve to the rectus femoris enters the upper part of the muscle and sends a branch to the hip-joint. The nerves to the three vasti are all long nerves which are prolonged downwards through the muscles and end in the kneejoint. The nerve to the vastus medialis occupies the upper end of the subsartorial canal, where it lies to the outer side of the femoral artery. It leaves the canal by diving into the substance of the vastus medialis. Its terminal twig supplying the knee-joint is the largest articular branch derived from the femoral. The subcrureus is supplied by the nerve to the vastus intermedius.

Action .—The four parts of the muscle extend the knee-joint. When the hip-joint is extended, the attachment of the straight head is the fixed point from which the rectus femoris pulls; but when the hip-joint is flexed, the straight head is relaxed, while the reflected head is now in line with the rest of the muscle, and is the effective head, by pulling on which the rectus femoris extends the knee-joint. The rectus femoris is also concerned in flexing the hip-joint. During extension of the knee-joint the synovial membrane which occupies the front part of the joint is relaxed, and the subcrureus is concerned in pulling it upwards, and thereby prevents it from being infolded and nipped between the bones.

The femoral (anterior crural) nerve is the largest branch of the lumbar plexus. Its fibres are derived from the second, third, and fourth lumbar nerves. In the iliac fossa the nerve lies in the interval between the psoas major and iliacus muscles, and this relationship to the two muscles is maintained as it descends into the thigh behind the inguinal ligament. In the upper part of the femoral triangle it lies to the outer side of the femoral artery, a part of the psoas muscle intervening between the two. Some little distance below the inguinal ligament it subdivides into two sets of branches : a superficial or anterior set, consisting of nerves which are chiefly cutaneous; and a deep or posterior set of muscular branches with one cutaneous nerve, the saphenous.



Fig. 349. —The Front and Inner Side of the Thigh.

The sartorius has been partially removed in order to expose the femoral artery in the subsartorial canal.



The branches are conveniently divided into intra-abdominal and femoral.

The intra-abdominal branches arise from the nerve above the level of the inguinal ligament, and consist of three or four branches supplying the iliacus muscle, and a branch to the femoral artery.

The branch to the femoral artery forms a network on the vessel. From this network a subsidiary network follows the profunda femoral artery and its second perforating branch; an ultimate twig passes into the nutrient foramen of the femur.

The femoral branches arise in the femoral triangle.

The branches of the anterior division are muscular branches to the sartorius and pectineus, and the intermediate and medial cutaneous nerves.

The branches of the posterior division are the four nerves supplying respectively the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius (from these nerves genicular branches to the hip and knee joints are derived), and the saphenous nerve.

Adductor Muscles—Gracilis (Fig. 349)— Origin. —The lower part of the anterior or femoral surface of the body of the os pubis close to the symphysis; and the front of the inferior pubic ramus close to its inner border.

Insertion. —The upper part of the inner surface of the shaft of the tibia above the semitendinosus, its insertion being embraced by that of the sartorius.

Nerve-supply .—The anterior or superficial division of the obturator nerve.

Action. —Adducts the thigh and flexes the knee-joint. It is also a medial rotator of the leg.

The gracilis is flat and strap-like in the upper third of the thigh. In the middle third it becomes thick and narrow, and gradually tapers into a long, narrow, round tendon which finally expands at its insertion. It occupies the inner aspect of the thigh, its two surfaces being directed inwards and outwards, and its borders forwards and backwards. In the lower third of the thigh the tendon has the sartorius in front of it, and the semitendinosus behind it; it is separated from the medial ligament of the knee-joint by a bursa.

Adductor Longus (Fig. 349)— Origin. —By a narrow tendon attached to a depression on the femoral surface of the body of the os pubis close to its inner edge and immediately below the pubic crest.

Insertion. —The inner lip of the linea aspera of the femur.

Nerve-supply. —The anterior or superficial division of the obturator nerve.

Action. —Adducts the thigh and rotates it outwards.

I he adductor longus is a flat, triangular muscle, its direction being downwards, outwards, and backwards. The tendon of origin is thick and narrow; as it extends downwards it broadens, and descends for some considerable distance along the inner edge of the muscle. It lies to the inner side of the pectineus, and in front of the adductor brevis, the anterior or superficial division of the obturator nerve, and the adductor magnus. The femoral vessels are in front of it, and the profunda femoral vessels behind it.

Adductor Brevis — Origin .—The lower part of the femoral surface of the body of the os pubis, and from the inferior pubic ramus following and immediately lateral to the attachment of the gracilis.

Insertion . — To a line extending downwards from a little way below the back of the lesser trochanter to the linea aspera, and to the upper part of the linea aspera. The attachment extends downwards to about the middle of the shaft of the femur.

Nerve-supply . — From the anterior or superficial division of the obturator nerve, sometimes from the posterior division of the nerve, and occasionally from both.


Action . — Adducts the thigh and rotates it outwards.

The adductor brevis is quadrilateral, and is directed downwards, outwards, and backwards. It lies behind the pectineus and adductor longus, and in front of the adductor magnus. The anterior division of the obturator nerve and the profunda femoral artery are in front of it, and the posterior division of the nerve behind it. Passing through it arej'the first two perforating branches of the profunda femoral artery.

Adductor Magnus (Fig. 351)— Origin .—-The whole length of the ischio-pubic ramus, its attachment extending outwards to the inferior aspect of the ischial tuberosity.

Insertion .—The muscle is attached to practically the whole length of the shaft of the femur. From a point a little way below the back of the greater trochanter the attachment extends downwards, follow ing the inner side of the gluteal tuberosity, to the linea aspera, wher it is attached to the inner lip. From the linea aspera it passes dowr wards to the medial supracondylar line. The attachment to th supracondylar ridge is interrupted, as here the muscle fibres end in tendinous arcade, arching over the femoral vessels, and attache

above to the upper part of the supra condylar line, below to the adductc tubercle. The adductor tubercle, situate on the upper aspect of the medial condyh gives attachment to the main tendon c the muscle.

Nerve-supply .—The posterior or dee division of the obturator nerve, th branches of which enter the anterio surface of the muscles. The part of th muscle which consists of fibres arisin from the ischial tuberosity is suppliei by a branch of the sciatic nerve, whic] passes into the muscle from behind.


The part of the adductor magnus supplie by the sciatic nerve is derived from the mm culature which gives rise to the hamstrin muscles.


Action .—Adducts the thigh and rotate it outwards. The part of the muscl stretching from the ischial tuberosity t< the adductor tubercle assists in extendinj the hip-joint.

The adductor magnus is triangular o fan-shaped. The uppermost fibres ar horizontal; the succeeding fibres are ob lique; and those arising from the ischia tuberosity are almost vertical. An uppe part, lying above and behind the rest o the muscle, and inserted into the inne side of the gluteal tuberosity, is triangula Fig. 351.— View of Muscles f n outline, and, being more or less inde

posed by Removal of

Pectineus and Adductor minimus. 1 he attachment of the rnusct

Longus. to the linea aspera is interrupted by fou

tendinous arcades, which give passage t< the perforating branches of the profunda femoral artery. In front of th< adductor magnus muscle are the adductor brevis, the adductor longus the posterior division of the obturator nerve, and the profundi femoris artery. Behind it are the hamstring muscles and the sciatii nerve.


The adductors as a group are a very powerful set of muscles coming more especially into play when a rider grasps the saddle with his knees; they are therefore called ‘ the rider’s muscles.’

Obturator Externus (Fig. 348)— Origin .—The inner two-thirds of the superficial aspect of the obturator membrane, and the adjacent parts of the body of the os pubis and of the ischio-pubic ramus.

Insertion .—The trochanteric fossa of the femur.

Nerve-supply .—A branch of the posterior division of the obturator nerve, arising in the pelvic cavity and entering the deep surface of the muscle.

Action .—Adducts the thigh and rotates it outwards.

The obturator externus is somewhat triangular, and is directed at first outwards, and then backwards and upwards. Its rounded tendon is closely applied to and imprints a slight groove on the back of the neck of the femur. Lying in front of it are the pectineus and the ilio-psoas; at its origin from the ischio-pubic ramus it is overlapped by the adductor brevis. It is in close contact with the lower and back part of the capsular ligament of the hip-joint, a bursa intervening between them. Behind its tendon, at the back of the neck of the femur, lie the adjoining edges of the gemellus inferior and quadratus femoris. The anterior division of the obturator nerve crosses its upper edge, and the posterior division of the nerve passes through its upper part, the two nerves descending in front of it. On its deep aspect, between it and the obturator membrane, are the two terminal branches of the obturator artery.

The obturator nerve is a branch of the lumbar plexus. It arises by three roots from the second, third, and fourth lumbar nerves; the upper root from the second lumbar nerve may be absent. A further description of the nerve is given in the section on the abdomen (q.v.). It escapes from the pelvic cavity by passing through the obturator canal, which is bounded above by the groove on the inferior aspect of the superior pubic ramus and below by the upper free crescentic margin of the obturator membrane and the muscles attached thereto. In the obturator canal it divides into two divisions—superficial or anterior, and deep or posterior. The anterior division winds over the upper edge of the obturator externus, and then descends in front of the adductor brevis, but behind the pectineus and the adductor longus, in which it ends. This division communicates with the accessory obturator nerve (when present).

Branches.—Articular to the hip-joint, which arises in the obturator canal and reaches the joint by passing through the acetabular notch; muscular to the gracilis, adductor longus, and adductor brevis, an occasional branch supplies the pectineus; arterial to the femoral artery; and a cutaneous branch which communicates with branches of the saphenous and of the medial cutaneous to form the subsartorial plexus on the deep aspect of the sartorius muscle. A branch of the subsartorial plexus becomes superficial between the posterior border of the sartorius and the anterior border of the gracilis; it supplies the skin on the inner side of the thigh for a variable extent.

The posterior division passes through the upper part of the obturator externus and descends between the adductor brevis in fronl and the adductor magnus behind. It furnishes the following branches muscular to the obturator externus, adductor magnus, and ar occasional branch to adductor brevis; and an articular to the kneejoint, called the geniculate branch. This geniculate branch firsl descends in front of the adductor magnus, but passing through the muscle a little way above the opening for the femoral artery, it gain' the popliteal space. In the popliteal space it lies behind and to the inner side of the popliteal artery. Opposite the knee-joint it passe' forwards, accompanies the middle geniculate artery, and enters the knee-joint from behind. The geniculate nerve is occasionally absent.

Accessory Obturator Nerve. —This nerve is present in about 30 pei cent, of bodies. It is comparatively small in size, and arises by twe roots from the anterior primary divisions of the third and fourtl lumbar nerves, the roots being interposed between those of the femora' and obturator nerves. It descends along the inner border of the psoa' major, close to the brim of the pelvic cavity, where it lies deeply tc the external iliac vessels. It passes downwards in front of the superioi pubic ramus into the thigh, where it lies deeply to the pectineus, anc divides into the following branches : articular to the hip-joint; £ muscular branch entering the deep surface of the pectineus; anc a communicating branch to the anterior division of the obturatoi nerve.

The Subsartorial (Hunter’s) Canal (Fig. 352).—In the femoral triangle the main artery of the limb, here known as the femoral artery, lies ir front of the hip-joint. Thence it extends downwards, and at the same time inclines backwards, approaching the obliquely disposed shaft ol the femur as it does so (Fig. 354). In the lower part of the thigh il gains the back of the femur, and as in this situation it is containec in the popliteal space, it is here called the popliteal artery. In passing from the front to the back of the limb the femoral artery occupies an interval between the extensor and adductor muscle groups, and is embedded in the connective tissue of the antero-medial intermusculai septum. This intermuscular interval, which in vertical extent corresponds to about the middle third of the thigh, is known as the subsartorial canal. It is bounded in front and to the outer side by the innermost extensor muscle, the vastus latefalls, behind and to the inner side by the adductor longus, the most anterior of the adductoi group. The roof of the canal is provided by the sartorius, which muscle, after crossing the front of the upper part of the thigh obliquely passes vertically downwards on its inner aspect, and occupies superficially the interval between the extensor and the adductors. Frorr the disposition of the muscle it is obvious that the antero-media. intermuscular septum must be continuous with the sheath of the sartorius, by means of which its continuity with the fascia lata ensheathing the thigh muscles is attained. The layer of the sheath of the sartorius, investing the deep aspect of the muscle, is relatively thick and strong, md provides the canal with an aponeurotic roof, which may be seen stretching from the vastus medialis on the one side to the adductor ongus on the other when the sartorius muscle is removed. The vertical extent of the subsartorial canal is limited above by the apex of

he femoral triangle, the point at which the femoral artery sinks deeply o the sartorius. The lower imit is the opening or deficiency n the adductor magnus, which s situated immediately below

he lower edge of the adductor ongus, and through which the

emoral artery passes to become xmtinuous with the popliteal.

Contents. —The femoral artery md its branches; the corresponding part of the femoral /ein and its tributaries; the saphenous nerve; and the nerve

o the vastus medialis muscle, vhich occupies the upper part of

he canal only. The femoral artery (Fig. 349) extends from the inguinal liganent above to the opening in he adductor magnus below. It s continuous above with the external iliac artery, and below vith the popliteal. It occupies he upper two-thirds of the thigh, tnd its direction is downwards md backwards. When the thigh s partially flexed upon the ibdomen, and at the same time s slightly abducted and rotated mtwards, the course of the vessel may be indicated on the surface by drawing a line from L point midway between the

interior superior iliac spine and the symphysis pubis to the adductor ubercle of the femur, or, if this tubercle cannot be felt, to the picondyle on the inner aspect of the medial condyle of the femur, rhe upper two-thirds of this line represents the position of the vessel.

The upper part of the vessel is contained in the femoral triangle, and s quite superficial. The lower part is deeply situated, and occupies -he subsartorial canal. About ij to 2 inches below the inguinal igament it gives off a large branch, the arteria profunda femoris,


Fig. 352. — Showing Structures exposed by Removal of Sartorius : Femoral Vein cut away.

below which it undergoes a sudden diminution in size. For conve ence of description, the femoral artery is divided into’ two parts, ' first part lying in the femoral triangle, and the second part occupy the subsartorial canal.

First Part. —The first part of the femoral artery extends from lower border of the inguinal ligament to the apex of the feme triangle.

Relations — Superficial or Anterior .—The skin; the superfk fascia, in which the superficial circumflex iliac vein, the anter femoral cutaneous vein, and one or two superficial lymphatic glai are embedded; the fascia lata; the anterior wall of the femoral shea in the upper part of which the femoral branch of the genito-femo nerve is embedded; the medial cutaneous nerve, represented by two more trunks; and branches of the medial cutaneous nerve cross 1 vessel from without inwards.

Deep or Posterior .—The artery lies successively on the psoas a pectineus muscles. In the upper part of the triangle it is separai from the psoas by the deep layer of the femoral sheath and the nei to the pectineus. In the lower part of the triangle it is separated fn the pectineus by the femoral vein and the profunda femoral vess< which lie behind the femoral vein.

Lateral .—The femoral nerve, which is separated from the art( by a narrow interval occupied by a part of the psoas muscle; 1 saphenous nerve and the nerve to the vastus medialis muscle, i former being nearer to the artery; and the profunda femoral art( for a short distance below its origin.

Medial .—Immediately below the inguinal ligament the femo vein lies to the inner side of the artery, but as the vein inclines obliqu< downwards and outwards relatively to the artery and below occup a deeper plane, it lies behind the artery in the lower part of 1 triangle.

Second Part. —The second part of the artery lies in the subsartor canal and extends from the apex of the femoral triangle to the op( ing in the adductor magnus, where it becomes continuous with t popliteal artery.

Relations. —As this part of the artery lies in the subsartorial can the muscles forming the walls of this passage are necessarily in relati to it (p. 580), the vastus medialis being in front and to the outer si( the sartorius in front and to the inner side, and the adductor long behind. The femoral vein is, for the most part, behind, but inclini outwards it lies somewhat to the outer side of the artery in the lov part of the canal. The saphenous nerve lies at first to the outer si of the artery, but crosses in front of it, and at the lower end of t canal lies to its inner side. The nerve to the vastus medialis lies its inner side in the upper part of the canal, but parts company wi the artery by diving into the substance of the muscle which it suppli The subsartorial plexus and the saphenous vein, which follows t hinder edge of the sartorius, are superficial but not direct relations.


The branches of the femoral artery may be arranged in two sets: t) Arising in'the femoral triangle. These branches are as follows: he superficial circumflex iliac, superficial epigastric, and superficial



Fig. 353. —The Front and Inner Side of the Thigh (Deep Dissection).

external pudendal arteries all arise close below the inguinal ligament. The deep external pudendal and arteria profunda femoris arteries arise at a lower level. Small irregular twigs supply the neighbouring muscles and skin, and the lymphatic glands.


(2) Arising in the subsartorial canal are the descending genicul; and muscular branches.

The superficial circumflex iliac artery may arise in common wil the superficial epigastric. It usually traverses the fascia lata abo^ and to the outer side of the saphenous opening. It extends oblique! upwards and outwards parallel to and slightly below the inguin; ligament, and ends by supplying the skin in the neighbourhood of tl anterior superior iliac spine. It supplies small muscular branches 1 the superficial inguinal glands, and anastomoses with the deep circun flex iliac, the superior gluteal, and the lateral femoral circumflex arterie

The superficial epigastric artery becomes superficial by passir through the cribriform fascia at the upper part of the saphenous opei ing. It passes upwards and inwards, crosses in front of the inguin; ligament, and gains the abdominal wall, where it may extend as hig as the umbilicus. It is chiefly distributed to the skin of the anteric abdominal wall, but also supplies twigs to the inguinal glands; it anast( moses with the inferior epigastric artery.

The superficial external pudendal artery traverses the cribrifori fascia covering the saphenous opening, and passes inwards in fror of the spermatic cord or the round ligament (according to the sex) t be distributed to the skin of the suprapubic region and of the scrotur and penis in the male, and of the labium majus in the female. 1 supplies branches to the inguinal (pubic) glands, and anastomose with the deep external pudendal and with branches of the interne pudendal artery.

The deep external pudendal artery is larger, arises at a lower leve and is on a deeper plane than its superficial namesake. It passe inwards deeply to the fascia lata, and lies on the pectineus (in fron of or behind the femoral vein) and the adductor longus. It traverse the fascia lata towards the inner side of the thigh, and is distribute* to the skin of the scrotum and of the perineum in the male, and to th labium majus in the female. It also gives small branches to th muscles upon which it lies, and anastomoses with the superficial externa pudendal and with branches of the internal pudendal artery.

The four arteries just described are known as the cutaneous arterie of the groin.

The arteria profunda femoris or deep femoral artery (Fig. 353), th largest and most important branch, arises from the outer side of tin femoral artery at a point from i| to 2 inches below the inguinal liga ment. It passes downwards in front of the psoas, and lies for a shori distance to the outer side of the parent trunk. Below the origin o its lateral femoral circumflex branch it inclines inwards on to th< pectineus, and comes to lie behind the femoral artery, its companioi vein, which is in front of it, and the femoral vein intervening betweer the two. At the upper edge of the adductor longus it become: separated from the femoral artery as it passes downwards behinc that muscle, and at the same time inclines outwards, coming into close relationship with the linea aspera at the back of the femur. The adductor brevis and at a lower level the adductor magnus are behind it. It rapidly diminishes in size, and ends as the fourth perforating artery.

Branches. —The medial and lateral femoral circumflex arise in the femoral triangle; the four perforating arteries arise from the vessel as it lies behind the adductor longus.

The lateral femoral circumflex artery is large, and arises from the outer side of the arteria profunda femoris close to its origin. It passes outwards between the sartorius and rectus femoris superficially and the vastus intermedius deeply. Branches of the femoral nerve lie both in front of and behind it. It supplies a few muscular twigs, and ends by dividing into three sets of branches—ascending, transverse, and descending.

The ascending branch passes upwards under cover of the tensor fasciae to the region of the anterior superior iliac spine, where it anastomoses with the superior gluteal and circumflex iliac arteries. It supplies muscular branches to the rectus femoris, the gluteus medius and gluteus minimus, and an articular branch to the hip-joint.

The transverse branch is usually represented by two arteries which dive into the vastus lateralis muscle and wind round the outer side of the femur. One of them pierces the femoral insertion of the gluteus maximus and reaches the back of the thigh, where by anastomosing with the first perforating artery, the sciatic, and the transverse branch of the internal circumflex, it helps to form the cruciate anastomosis.

The descending branch is the largest of the three, and is usually multiple. Its branches pass downwards with the nerve to the vastus lateralis, and follow the anterior border of that muscle. A long terminal branch traverses the lower part of the vastus lateralis and reaches the outer side of the knee, where it anastomoses with the lateral superior genicular branch of the popliteal artery. Muscular branches supplying the vastus lateralis and vastus intermedius anastomose with the perforating arteries.

ihe medial femoral circumflex artery is smaller than the lateral. Arising from the inner and back part of the arteria profunda femoris, opposite the origin of the lateral circumflex, it passes directly backwards on the inner side of the femur. It first lies between the pectineus and psoas major, and, on a deeper plane, occupies an interval between the adductor brevis and obturator externus, where it ends by dividing into two branches—ascending and transverse. It supplies large muscular branches to the obturator externus and to the adductor muscles, and an articular branch which passes through the acetabular notch

with a branch from the obturator artery, with which it varies inversely in size.

The ascending branch follows the tendon of the obturator externus to the trochanteric fossa of the femur, where it anastomoses with the superior and inferior gluteal and first perforating arteries, thus taking part in the trochanteric anastomosis.

Ihe transverse branch maintains the direction of the parent trunk, and passes backwards between the adductor magnus and the quadratus femoris to the gluteal region, where by anastomosing with th transverse branch of the lateral circumflex, the first perforating, an the inferior gluteal arteries, it helps to form the cruciate anastomosis


Fig. 354.—The Relations of the Femoral Artery and its Branches

to the Skeleton.

The four perforating arteries (Fig. 354) all pass backwards rour the inner side of the femur, lying between the bone and the tendinoi arcades of the adductor magnus. The first and second arteries traverse both the adductor brevis and the adductor magnus, whilst the third and fourth traverse the adductor magnus only. On reaching the back of the thigh, all four arteries give off muscular branches to the hamstring muscles, branches to the sciatic nerve, and cutaneous branches which follow the lateral intermuscular septum and supply the skin. On the back of the thigh the first perforating artery traverses the femoral attachment of the gluteus maximus, while the lower three pass through the femoral head of the biceps. Terminally the perforating arteries traverse the lateral intermuscular septum, and end in the substance of the vastus lateralis. From the second perforating artery (sometimes from the third) the nutrient artery to the shaft of the femur is derived. The first perforating artery has a branch which ascends on the back of the adductor magnus, and takes part in the formation of the cruciate anastomosis, whereby it communicates with the circumflex and inferior gluteal arteries. It has a further communication with the latter artery by means of its branches to the sciatic nerve, which anastomose with the companion artery of sciatic nerve. The successive perforating arteries freely communicate with one another, and the last perforating artery anastomoses with branches of the popliteal artery. These arteries thus form a series of communicating links in an anastomotic chain at the back of the thigh, whereby blood may flow from the inferior gluteal artery above into the popliteal artery below.

The anastomotic chain at the back of the thigh is multiple, consisting of

(1) direct communications between the inferior gluteal, the medial circumflex, and the successive perforating arteries at the back of the adductor magnus;

(2) communications between the muscular branches; (3) communications between the branches supplying the sciatic nerve.

Branches 0! the Femoral Artery in the Subsartorial Canal. —Small muscular twigs are derived from the femoral artery as it lies in the femoral triangle, but the larger muscular branches come off from the lower part of the trunk in the subsartorial canal. They are mainly distributed to the muscles forming the walls of the canal.

The descending genicular artery (Fig. 354) arises from the femoral artery towards the lower end of the subsartorial canal, and divides into a saphenous and a musculo-articular branch. In some cases the two branches arise independently. The saphenous branch traverses the fascial roof of the subsartorial canal, appears at the hinder edge of the sartorius, along which it descends in company with the saphenous nerve to the inner side of the knee. It takes part in the anastomosis on the inner side of the knee, and ends by supplying the skin on the inner side of the leg for a variable distance. The musculo-articular branch first descends parallel to the tendon of the adductor magnus. Changing its direction, it passes outwards through the vastus medialis and crosses the front of the lower end of the femur obliquely. Its terminal branches end in the anastomosis between the two superior genicular branches of the popliteal artery.


Varieties—The Femoral Artery.— (i) In rare cases the femoral artery replaced by a large artery on the back of the thigh accompanying the sciat nerve, and continuous above with an enlarged inferior gluteal artery. In th condition the external iliac artery ends in the arteria profunda femoris.

(2) Occasionally the femoral artery divides below the origin of the arteri; profunda femoris into two trunks of equal size, which reunite to form one truu at a lower level.


Fig. 355 - Deep Dissection of the Femoral Triangle.


\ 1C P ro ^ n da femoris normally arises from the femoral from ii to

2 inches below the inguinal ligament, but the level at which the femoral artery divides is very variable. The profunda femoral artery may arise from the external mac above the level of the inguinal ligament. In rare cases the subdivision of the femoral artery takes place at a low level, even as low as 4 inches below the inguinal ligament.

The lateral circumflex artery is very variable. It may arise from the femoral,



is is usually the case in low origin of the profunda femoris. It may be re)resented by two arteries arising variably from the profunda femoris or from the femoral.

The medial circumflex artery is more constant. It may arise in common vith the lateral circumflex; from the femoral; from the inferior epigastric; or 'rom the external iliac.

The Descending Genicular Artery. —In rare cases the superficial branch s enlarged, and extends downwards to the medial malleolus in company with

he long saphenous vein. This condition resembles that found normally in some animals, where the vessel is known as the saphenous artery.

Abnormal Branches. —The inferior epigastric, the deep circumflex iliac, and the obturator artery have all been known to arise from the femoral artery.

The femoral vein extends upwards from the opening in the adductor nagnus to the lower border of the inguinal ligament, where it is continuous with the external iliac vein. In the lower part of the subsartorial canal it is behind and to the outer side of the femoral artery. As it ascends it passes directly behind the artery, in which position it mters the femoral triangle. In the femoral triangle it inclines inwards and forwards, and below the inguinal ligament it lies to the inner side of and in the same plane as the femoral artery.

The tributaries correspond to the branches of the femoral artery, with the addition of the long saphenous vein, which joins the femoral vein in the femoral triangle. The veins corresponding to the three superficial branches of the femoral artery are tributaries of the long saphenous vein; they join this vein independently or more usually by a common trunk.

The femoral vein is provided with from one to five valves. The most constant is found at its upper end above the junction of the long saphenous vein, and controls the return of venous blood from the lower limb.

The profunda femoris vein lies in front of its companion artery, and in the lower part of the femoral triangle intervenes between it and the femoral vessels, which are here directly in front of it. It is provided with several valves.

The obturator artery (Fig. 355) arises from the anterior division of the internal iliac, and lies, for the greater part of its course, on the outer wall of the pelvic cavity. It passes through the obturator canal, and divides into two terminal branches, medial and lateral. The two pass downwards deeply to the obturator internus muscle, and follow the inner and outer margins of the obturator membrane respectively. The medial branch supplies the obturator externus and adjacent adductor muscles. The lateral branch divides into two. A pubic branch passes inwards, and, anastomosing with the medial branch, completes an arterial circle surrounding the obturator membrane. The other passes outwards below the acetabulum to the ischial tuberosity, where it supplies the origins of the hamstring muscles and anastomoses with the inferior gluteal artery; it also gives an acetabular branch which passes through the acetabular notch and supplies the hip-joint. Both terminal branches of the obturator anastomose with the medial circumflex artery of the arteria profunda femoris.


The Hip-Joint

The articular surfaces taking part in the formation of the joint ; the head of the femur and the acetabulum. The ligaments are a Cc sular ligament supplemented by accessory ligaments, together with i ligament of head of femur, the labrum acetabulare, and the transve: ligament.

The capsular ligament is very strong, and completely surrounds t joint. Its attachments to the hip-bone are: Above and behind it


Fig. 356- The Right Hip-Joint viewed from in Front (after Sobotta

The weak area of the capsular ligament may have a deficiency through whic the synovial cavity communicates with the bursa underlying the tendon ( the psoas.

attached to the bone some little distance away from the edge of tb acetabulum, being fixed above to the groove giving origin to th reflected head of the rectus. In front its attachment is close to th margin of the acetabulum, and it is here adherent to the labrur acetabulare. Below it is attached to the transverse ligament, whic bridges across the acetabular notch. Its femoral attachments are Above to the front part of the greater trochanter and the upper tubercl of the neck. In front to the upper rough part of the trochanteric line which is on the front of the femur, and extends between the upper and >wer tubercles of the neck. Behind to a faint ridge which extends pwards for a short distance from the lower tubercle of the neck, and es to the inner side and in front of the lesser trochanter. Above this idge the capsular ligament has no direct attachment to the bone, but as a more or less free edge (Fig. 357), from under cover of which the /novial membrane may protrude in certain joint movements. This

ee edge corresponds in position to a line marking the junction of the uter third and inner two-thirds of the posterior surface of the femoral eck.

From the above description it can be realized that the only part of the neck Fich is not clothed by the capsular ligament is the outer third of the posterior jrface. This part of the neck may be involved by a fracture which is termed xtracapsular in contra-distinction to an intracapsnlav fracture which involves ny part of the neck situated within the limits of the capsule.

The fibres of the capsular ligament are disposed both longitudinally nd circularly. The longitudinal fibres are the more superficial, and re mainly provided by the accessory or supplementing ligaments, die circular fibres, or zona orbicularis, are the deeper, and are most pparent on the posterior and inferior aspects of the joint, where the

apsular ligament is relatively thin and the longitudinal fibres are more >r less deficient.

In certain situations the capsular ligament is thickened and itrengthened by accessory or supplementing ligaments known as the lio-femoral, ischio-femoral, and pubo-femoral ligaments.

The ilio-femoral ligament (Fig. 356) is situated on the anterior ispect of the joint, and is a triangular band, the apex of which is ittached above to the anterior inferior iliac spine below the origin of

he straight head of the rectus femoris. From its upper attachment he fibres of the ligament spread out fanwise to its base, which is ittached below to the trochanteric line and extends from the upper

o the lower tubercle of the neck. The central part of the ligament is relatively thin, but the marginal parts are thickened bands, and together present the appearance of an inverted Y. They account for the ‘ Y -ligament of Bigelow by which name it is sometimes known. The Lnner band is almost vertical, and is attached below to the lower tubercle of the neck. The outer band, shorter than the inner, passes obliquely downwards and outwards, and i§ attached to the upper tubercle of the neck.

The ischio-femoral ligament (Fig. 357) is a triangular band which occupies the posterior aspect of the joint. Its base is attached to the Lschium close to the acetabular margin. The lowest fibres are attached to the upper lip of the groove below the acetabulum, and are disposed to a certain extent on the inferior aspect of the joint. From its ischial attachment the ligament stretches obliquely upwards and outwards, gains the upper aspect of the joint, and is attached for the most part to the deep or inner aspect of the greater trochanter immediately in front of the depression giving attachment to the obturator internus and the two gemelli. Some of its fibres, especially the lower, spre^ out and are continuous with the fibres of the zona orbicularis. Fro the foregoing description it may be gathered that the ischio-femor ligament has a somewhat spiral disposition extending from the inferii aspect on to the posterior, and thence on to the superior aspect of tl joint.

The pubo-femoral ligament (Fig. 356) is a triangular band with i base at the hip-bone, where its fibres are attached to the ilio-pub eminence and to the superior pubic ramus ; they often extend inwan as far as the pubic tubercle. Some of its lower fibres are usually cor tinuous with those of the obturator membrane. The main part of tl ligament occupies the medial aspect of the joint, and its fibres convey


towards and meet the medial band of the ilio-femoral ligament, wifi which it is attached to the inferior tubercle of the neck; the lowe fibres gain the posterior aspect of the joint, and are attached to th ridge which extends upwards from the inferior tubercle of the neck fi the inner side, and in front of the lesser trochanter.

Between the pubo-femoral ligament and the inner vertical band 0 the ilio-femoral ligament the capsular ligament clothing the front 0 the joint is relatively weak and thin. The tendon of the psoas is hen lying directly in front of it, and it may present a deficiency througl which the synovial membrane of the joint is continuous with a burs; underlying the psoas.

It may be noted that the three main accessory or supplementing ligament of the hip-joint are all triangular: the ischio-femoral and the pubo-femoral


dth their bases or more extensive attachments at the hip-bone and their more imited attachments at the femur; the ilio-femoral ligament, on the other land, has its more limited attachment at the hip-bone, while its femoral attachnent is the more extensive.

Between the outer oblique band of the ilio-femoral ligament and he ischio-femoral ligament the longitudinal fibres of the capsular igament, stretching from the groove above the margin of the acetabllum (giving attachment to the reflected head of the rectus femoris) o the greater trochanter, are sometimes regarded as an independent igament, the ilio-trochanteric band (Fig. 357).


^ IG - 358.—The Head of the Femur withdrawn from the Acetabular Cup to show the central part of the llgamentum teres spreading out and surrounding the fat in the fovea acetabuli, while its two

Thick Lateral Margins pass through the Cotyloid Notch.

When the hip-joint is opened, the deepest fibres of the capsular igament are seen to be reflected from their femoral attachments on to "he neck of the femur, which they clothe, and extend upwards as far is the margin of the articular cartilage of the head. Some of these reflected fibres form distinct bands best marked on the front and upper aspects of the neck of the femur and termed the retinacula (Fig. 359).

The ligament of head of femur (Fig. 358) extends between the head

the femur and the acetabulum, and is, as regards its position, an wtracapsular structure. At one end it is attached as a relatively narrow flattened band to the small rough area interrupting the articular cartilage clothing the head of the femur (pit on head of femur). As it approaches the floor of the acetabulum it broadens into a triangular sheet, the margins of which are thickened bands attached on either


Fig. 359.—A Coronal Section through the Hip-Joint to show the D

POSITION OF THE LIGAMENT OF HEAD WHEN THE HEAD OF THE FEMUR LODGED IN THE ACETABULAR CUP.

The synovial membrane is indicated by a red line.

are in apposition, the ligament of head is interposed between th< articular surfaces (Fig. 359).

Morphologically the ligament is a thickened infolding of the synovial me brane, which has come into being as a result of the way in which the articu surfaces of the hip-joint have expanded, and which has become compleh isolated at its femoral attachment.

The labrum acetabulare is a firm annular band of fibro-cartila which is implanted upon the brim of the acetabulum, and bridges ov


Fat in Acetabular Notch


side of the acetabular notch and extending for a little distance beyo the limits of the joint. The central part is thin, and consists of scattei fibres thickening the synovial membrane which ensheathes the lii ment of head of femur, and is attached with it to the margin of 1 large rough area interrupting the articular cartilage lining the acet; ulum (acetabular fossa), where it surrounds the pad of fat lod^ therein (Fig. 358). When the head of the femur and the acetabuli


Labrum Acetabulare Capsular Ligament x Retinacula


in Acetabuli Fossa


- Lig. of Head of Fe


.-Hip Bone


Articular Cartilage









THE LOWER LIMB


595


ie acetabular notch. It serves to deepen the acetabular cup. Its bres are oblique in direction, and are for the most part attached to ie outer and inner surfaces of the brim, but opposite the acetabular otch they are attached to the transverse ligament. The outer surface f the labrum is convex, whilst the inner surface is concave and closely pplied to the head of the femur. The labrum is triangular in section, fie base being implanted on the brim of the acetabulum, and the apex ^presenting the free margin, which is so incurved as to grasp the head f the femur.

The transverse ligament

ridges over the acetabular otch. It is composed of hree bundles of fibres inimately blended with one nother. The superficial »undle is formed by that >art of the labrum acetalulare which stretches over he notch. The other two rnndles are more deeply >laced, and are arranged as wo decussating bands exending between the margins »f the notch, and blending fosely with the superficial mndle. Between the transverse ligament and the floor >f the acetabular notch is a pace whereby the fat lodged n the fovea acetabular fossa s continuous with the extra irticular fat, and which gives massage to articular vessels md nerves.

The Synovial Membrane.—

rhe synovial membrane may

>e traced from the femur, vhere it is attached to the 'ircumferential edge of the irticular cartilage covering the rounded head of the bone. Thence it masses downwards and outwards as a cylindrical sheath surrounding the neck of the femur, and clothing the retinacula as far as the line of ittachment of the capsular ligament. From this line it is reflected m to the deep aspect of the capsular ligament, which it lines completely, and extends to the margin of the acetabulum. At the margin

the acetabulum it is reflected on to the outer or superficial aspect d the labrum acetabulare, coming to an end at its free margin except n the region of the acetabular notch, where its line of attachment


Fig. 360. —View of Right Acetabulum,

SHOWING THE ACETABULAR LABRUM (L) ATTACHED ROUND THE MARGIN AND TO THE

Transverse Ligament (T).

Capsule is attached to labrum in front, but is a little distance away from it (C) behind, so that a synovial sulcus (S) lies between the two. IF, ilio-femoral band; R, rectus; H, dotted line showing attachment of base of ' ligament of head of femur.’


596


A MANUAL OF ANATOMY


is infolded into the joint, following the margin of the articular cartila^ bordering the acetabular fossa. From this margin the synovial men brane is prolonged as a tent-like arrangement surrounding the ligamei of head of femur and the pad of fat occupying the acetabular foss; As a complete investment to the ligament of head the synovial men brane may be traced to the femoral attachment of this band, where finally comes to an end around the margin of the pit of head of femur.

The synovial membrane is usually described as covering both aspects of tl labrum acetabulare, but it is most improbable that as such it covers the dee aspect, which is in contact with the head of the femur.

The so-called Haversian gland occupies the acetabular fossa c rough area of the acetabulum. It is simply a mass of fat invested b the ligament of head of femur and the synovial membrane.

Muscular Relations. —The hip-joint is deeply placed, and is buried i a thick mass of surrounding muscles. As the head of the femur i almost completely lodged in the acetabular cup, and the neck of th femur is almost completely clothed by the capsular ligament, th muscular relations of the joint are, for all practical purposes, those c the femoral neck. Further, the neck of the femur is so obliquely dh posed that structures lying above it must also be to a certain extent o: its outer side, while structures lying below it must also be to som extent on its inner side. Certain muscles which cross the joint pas from one aspect to another. For instance, the ilio-psoas passes down wards from in front of the joint to its lower and inner aspect in orde to gain the lesser trochanter; above, the pectineus lies in front of th pubo-femoral ligament, but in passing downwards and backwards t gain the back of the femur lies to the inner side of the neck of th femur; the main part of the obturator externus is to the inner side o the joint, but its tendon in passing outwards to gain the greate trochanter is applied to the posterior aspect of the femoral neck Keeping these facts in mind, the muscular relations of the joint ma] be classified as follows: In front: Sartorius, rectus femoris, ilio-psoas pectineus. Below and to the inner side: Ilio-psoas, pectineus, obturato: externus. Behind: Gluteus maximus superficially; the pyriformis obturator internus, the two gemelli, and quadratus femoris on a deepe plane, and the obturator externus in direct contact with the joint Above and to the outer side: Tensor fasciae latae, gluteus medius, gluteu: minimus, and the reflected head of the rectus.

Arterial Supply. —The articular arteries to the hip-joint are derivec from the two circumflex, the obturator, the superior and inferio: gluteal.

The articular arteries derived from the medial circumflex, or from the ob turator or from both vessels, and passing through the acetabular notch, suppb the fat lodged in the acetabular fossa, and may be traced into the ligament o head of femur. It has been thought that this ligament transmits the arteries which are responsible for the supply of the head of the femur, but the vessel:

in the ligament are so minute that they can convey little or no blood to th< bone.


THE LOWER LIMB


597


Nerve-supply. —The nerve-supply of the hip-joint is derived from the hree large nerves—the femoral, the obturator, and the sciatic—which upply the three muscle groups of the thigh: Femoral, by a branch rom the nerve supplying the rectus femoris; obturator, by a branch rom the anterior division; sciatic, by a branch from the nerve itself or rom the nerve to the quadratus, a nerve whose origin is closely ssociated with that of the sciatic, and of which it may be a branch.

The movements which occur in the joint are flexion, extension, abduction, dduction, rotation, and circumduction.

Flexion. —In flexion the thigh is drawn up towards the anterior abdominal rail. The extent of flexion possible depends upon the position of the kneefint, being greater when that joint is flexed and more limited when it is exended. This is due to the passive insufficiency of the hamstrings, these muscles •eing incapable, without special training, of elongating sufficiently to permit all extension of the knee-joint and full flexion of the hip-joint to occur simulaneously. The hamstrings are, therefore, concerned in limiting movement •oth at the hip-joint and at the knee-joint. If the knee-joint is flexed, flexion f the hip-joint is limited by the coming into contact of the soft parts on the ront of the thigh and on the anterior abdominal wall.

Extension is limited by the tension of the three chief accessory ligaments, "he hip-joint is extended when standing in the erect posture. In this position he line of the centre of gravity falls behind the centre of rotation at the hipoint, and there is consequently a tendency for the trunk to fall backwards ,t this joint. This tendency is counteracted not only by the tension of the [io-femoral and pubo-femoral ligaments on the front of the joint, but also by hat of the ischio-femoral ligament. During flexion and extension the neck I the femur is, owing to its oblique position, rotating about an imaginary line oughly corresponding to its own axis. During extension it is rotating forwards nd carrying the greater trochanter with it. The greater trochanter, to which me end of the ischio-femoral is attached, travelling forwards, is displaced farther -way from the attachment of the other end of the ligament to the ischial uberosity. Being spirally disposed, the ischio-femoral ligament is thus wound ip or tightened during extension, while it is unwound or relaxed during flexion. )wing to the fact that in the erect posture the weight of the body tends to iver-extend the hip-joint, and that this tendency is prevented by the tension if the strongest ligaments about the joint, the position can be maintained, as far -S the hip-joint is concerned, with a minimal expenditure of muscular energy. )wing to the greater width of the pelvis, the direction of the articular surface >f the acetabulum, and possibly the relative shortness of the ilio-femoral liganent, extension of the hip-joint is probably more limited in the female than n the male, and explains her characteristic gait.

Abduction is limited by the pubo-femoral ligament, the lower part of the apsule, and the tension of the adductor muscles.

Adduction is limited by the outer band of the ilio-femoral ligament and the ipper part of the capsule.

Rotation consists of a movement of the femur round a longitudinal axis, rhis axis is represented by a line passing from the centre of the head of the emur to a point at the middle of the intercondylar notch.

Rotation may take place outwards or inwards. Lateral rotation is limited )y the outer band of the ilio-femoral ligament; medial rotation by the ischioemoral ligament, and by the muscles in contact with the back of the joint. Hie range of rotation is about 60 degrees.

Circumduction consists of flexion, abduction, extension, and adduction, olio wing one another in succession.

The labrum acetabulare is an elastic extensible ring tightly grasping the head } f the femur in all positions of the joint. It plays a most important role, both n increasing the extent of the articular surface provided by the acetabulum


598


A MANUAL OF ANATOMY


and in maintaining the apposition of the articular surfaces without interfering in any way with their mobility.

The Ligament of Head of Femur. —Although this ligament is in a conditioi of tension in the position of adduction combined with flexion, it is not strong enough to have much influence in limiting the very forcible movements occurring in the joint. Its acetabular end is intimately associated with and surrounds th< Haversian gland or pad of fat lodged in 'the acetabular fossa. Its femora attachments must follow the displacements of the head of the femur occurring in the different joint movements. Consequently, as it is pulled by the heac of the femur in various directions, as it is tightened or relaxed, so it must in fluence the position and amount of fat occupying the acetabular fossa. Tha the amount of fat within the joint varies may be easily proved by examining the region of the acetabular notch of an intact joint when the neighbouring extra articular fat, which is continuous with the fat of the Haversian gland, has no been disturbed. If the joint be subjected to passive movements, at one momen this fat is apparently drawn into the joint through the acetabular notch, a another it escapes from the joint. That such an apparatus is a necessity arise; from the fact that the head of the femur is not a perfect sphere, and that th< various diameters of the acetabulum are unequal. Such being the case, in certaii positions of the joint—when, for instance, the shortest diameter of the heac of the femur coincides with the longest diameter of the acetabular cup—cavita tion or a spatial interval would occur between the articular surfaces (a cir cumstance which would seriously interfere with the mobility of the joint) wen there no material ready at hand to be interposed between the two. Thai material is provided by the ligament of head and the Haversian pad, the forme] being so disposed as to be always in the right place, and in the right degree o: tension or relaxation at the right moment.

Muscles concerned in the Movements—Flexion. —Ilio-psoas, rectus femoris sartorius, and pectineus. Extension. —Gluteus maximus, the hamstring muscles and the ischial part of the adductor magnus. Abduction. —Gluteus medius, gluteus minimus, the upper fibres of the gluteus maximus, tensor fasciae latae, and saitorius. Adduction. —The adductor muscles and the pectineus. Media] Rotation. The anterior fibres of the gluteus medius and minimus, the tensoi fasciae latae, the ilio-psoas, and the semitendinosus, especially when the knee is slightly flexed. Lateral Rotation. —The lower fibres of the gluteus maximus, the posterior fibres of the gluteus medius and minimus, pyriformis, obturatoi interims and gemelli, quadratus femoris, pectineus, the adductor muscles, and sartorius.

Bursae at the Hip-Joint. —The subpsoas bursa is situated between the tendon of the psoas and the anterior part of the capsular ligament in the interval between the ilio-femoral and pubo-capsular ligaments. Here the capsular ligament is very thin, and may present a deficiency through which the bursa is continuous with the synovial membrane of the joint. The bursa of the gluteus medius is situated between its tendon of insertion and the outer surface of the greater trochanter. 1 he bursa of the gluteus minimus is situated between its tendon of insertion and the anterior surface of the greater trochanter.

A bursa associatea with the gluteus maximus lies between its tendon of insertion and the vastus lateralis muscle.


THE LEG.

Landmarks. The sharp sinuous anterior border or crest of the tibia is entirely subcutaneous, and is easily felt; it serves as a guide to the tubercle, which is situated at its upper end and gives attach


THE LOWER LIMB


599


ment to the ligamentum patellae. The lower limit of the tubercle marks the level at which the popliteal divides into the anterior and posterior tibial arteries. The head of the fibula is a prominent landmark on the outer side of the leg; it is about i inch below the level of the upper surface of the lateral condyle of the tibia. The shaft of the fibula is for the most part obscured by muscles. It can be felt, however, in its lower fourth. The bone occupies a more posterior plane than the tibia. The prominence along the front of the leg in its upper two-thirds is mainly due to the fleshy belly of the tibialis anterior.

The medial and lateral malleoli are bold projections at the lower end of the leg, the medial being provided by the tibia, the lateral by the fibula. The malleoli are upon the same plane posteriorly, but the medial malleolus projects farther forwards than, and does not descend so low as, the lateral malleolus. This must be kept in mind in Syme's amputation at the ankle-joint. It should be carefully noted that, whilst the medial malleolus looks directly inwards, the medial tibial condyle has a slight inclination backwards as well as inwards. The tendons of the tibialis posterior and flexor digitorum longus may be felt behind the medial malleolus, the former being the larger and in closer contact with the bone. If the foot be inverted by raising its inner border, the tendon of the tibialis posterior will be more readily felt. The tendons of the peroneus longus and peroneus brevis are situated behind the lateral malleolus, where they lie one behind the other, the brevis tendon being in closer contact with the bone. Several tendons can readily be felt in front of the ankle-joint. From within outwards they are as follows: tibialis anterior, extensor hallucis longus, extensor digitorum longus, and peroneus tertius. All these tendons are best felt in the living subject when the foot is bent upon the leg.

The back of the leg is characterized by the prominence of the calf, which is produced by the gastrocnemius and soleus muscles. This prominence gives place inferiorly to the tendo-calcaneus (Achillis), which stands out boldly beneath the skin, and ends below at the calcanean tuberosity. On either side of the projection caused by the tendo-calcaneus there is a groove-like depression. The outer groove indicates the position of the short saphenous vein and sural nerve and the peroneal artery; the inner groove that of the posterior tibial vessels and nerve.

The course of the anterior tibial artery on the front of the leg is indicated by a line drawn from the superior tibio-fibular articulation to the centre of the front of the ankle-joint, midway between the two malleoli. This line practically coincides with the outer border of the tibialis anterior. The course of the posterior tibial artery corresponds with a line drawn from the centre of the popliteal space to a point midway between the tip of the medial malleolus and the point of the heel.

It is to be noted that in addition to the posterior tibial there is another large artery, the peroneal artery, on the back of the leg. In operations the guide to its position is the back of the fibula; the posterior


6 oo


A MANUAL OF ANATOMY


tibial lies between the two bones, except in the lower part of the le, where it lies on the back of the tibia (Fig. 361).

The anterior and posterior tibial arteries can be compressed simu taneously with one hand by placing the thumb in front of the ankli joint midway between the two malleoli, and the middle finger midwa between the tip of the medial malleolus and the point of the heel.

The long saphenous vein may be visible in front of the medi; malleolus, and from this point it may be traced upwards followin the medial subcutaneous surface of the tibia.


ong. Saph. Vn. Flex. Dig. Long.


Tibialis Post.


Tibialis Ant.\


Ext. Dig. Long.

Ant. Tib. Art. and Nv. v Intercss. Memb. Muse. Cut. Nv.„

Ant. Fib. Sept.

Peroneal Ms Peroneal Art.


Soleus-

Plex. Hall. Long./

Transv. Fib.

Post. Tib. Art. and Nv.


Post. Fig. Sept.-'


( Plantaris.


Gastrocnemius


Sht. Saph. Vn.


Pig. 361. A Iransverse Section through the Upper Part of the Le( to show the Intermuscular Septa and the Relative Positions oi the Three Chief Arteries.


The short saphenous vein is rarely visible. It lies behind th lateral malleolus, in the groove on the outer side of the tendo-calcaneus It ascends to the middle line of the back of the leg, where it lies in th< groove between the two heads of the gastrocnemius.

Deep Fascia. —The deep fascia is continuous above with the fascic lata of the thigh. In the region of the knee it is attached to the heat of the fibula, the condyles of the tibia, the patella, ligamentum patellae and tibial tubercle. In the leg it is attached to the crest and media border of the tibia. It is apparently interrupted by the medial subcutaneous surface of the tibia, but is represented there by a thin layei





THE LOWER LIMB


601


losely connected with the periosteum. At the ankle it is attached o the medial and lateral malleoli. The fibres are chiefly vertical in irection, but, in addition, there are transverse fibres, most marked t the back of the knee, and especially in the region of the ankle, where hickened bands of the transverse fibres of the deep fascia are known s retinacula. The deep fascia is very thin over the gastrocnemius, iut on the front and outer parts of the leg, more especially in its upper alf, it is very strong and dense, and here gives attachment to the uperficial fibres of the muscles which it covers. In the region of the

nee it receives accessions of fibres from the tendons of the quadriceps emoris, biceps femoris, sartorius, gracilis, and semitendinosus.

Intermuscular Septa. —In addition to the interosseous membrane, diich stretches from the lateral border of the tibia to the antero-lateral >order of the fibula, and lies between the flexor muscles on the back of he leg and the extensor muscles in front, there are three intermuscular epta intervening between the main muscle groups of the leg. These ire known as the anterior, posterior, and transverse fibular septa. The wo former are sometimes termed the anterior and posterior peroneal epta and are attached to the antero-lateral and postero-lateral borders )f the fibula respectively. They are continuous with the deep fascia uperficially, and with it complete the walls of a fibro-osseous com)artment containing the peroneus longus and peroneus brevis. They

eparate these muscles from the extensors in front and the flexors >ehind. The transverse septum occupies the back of the leg, and lies )etween the superficial flexors, or calf muscles, and the deep flexor nuscles. There are thus four fascial compartments containing four nuscle groups: the extensor muscles supplied by the anterior tibial lerve, the peroneal muscles supplied by the musculo-cutaneous nerve, he superficial flexors supplied by branches of the medial popliteal lerve given off in the popliteal space, and the deep flexors supplied )y the posterior tibial nerve. The posterior tibial vessels and nerve ire contained in the transverse intermuscular septum; the anterior

ibial vessels and nerve lie in front of the interosseous membrane and, )eing covered anteriorly by a thin layer continuous on either side with

he membrane, are to a certain extent embedded in it. The retinacula (annular ligaments) are situated in the region of

he ankle, and are simply thickened portions of the deep fascia, from vhich they may be artificially separated. They serve to confine and naintain the position of the strong tendons passing from leg to foot.

The peroneal retinaculum (external annular ligament) extends lownwards and backwards from the apex and posterior border of the ateral malleolus to the outer aspect of the hinder part of the calcaneum. tt bridges over the peroneal groove behind the lateral malleolus, and serves to keep the tendons of the peroneus longus and brevis in place, rhe two tendons are here invested by a common synovial sheath. The Lower part of the ligament is adherent deeply to the peroneal tubercle 3n the calcaneus. The tendon of the peroneus brevis is above the tubercle, that of the peroneus longus below it. Each tendon is here


602


A MANUAL OF ANATOMY


contained in a separate compartment, and provided with its owj synovial sheath, which in each case is continuous with, or a diver ticulum of, the common synovial sheath behind the lateral malleolus.


Fig. 362. The Structures between the Medial Malleolus

and the Heel.


The flexor retinaculum (internal annular ligament) (Fig. 362) extends obliquely downwards and backwards from the posterior border of the medial malleolus to the inner aspect of the hinder part ’of the calcaneus,


Iug. 363. I he Synovial Sheaths at the Ankle (Medial Aspect) (after L. Testut’s ‘ Anatomie Humaine - ).

It is continuous above both with the deep fascia of the leg and the transverse intermuscular septum, which here blend with one another. Its lower border gives origin to the abductor hallucis. It bridges across the grooves on the back of the lower end of the tibia, and con













THE LOWER LIMB


603


Peroneus Longus et Brevis —


Tibialis

Anterior


Extensor

Digitorum

Longus


Extensor

Hallueis

Longus


verts them into four canals containing, in order from within outwards: T) the tendon of the tibialis posterior; (2) the tendon of the flexor iigitorum longus; (3) the posterior tibial artery with a vena comes on either side of it, and the posterior tibial nerve ; (4) the tendon of the lexor hallueis longus. Each of the three tendons is invested by an ndependent synovial sheath. Passing through the flexor retinaculum ire the medial calcanean branch of the posterior tibial nerve and the nedial calcanean branch of the pos:erior tibial artery.

The extensor retinacula (anterior mnular ligament) (Fig. 364) consist )f two parts: An upper, situated on the front of the leg above the anklejoint, and called the superior extensor retinaculum; the lower lies in front Df the bend of the ankle, and is called the inferior extensor retinaculum.

The superior extensor retinaculum is a broad band extending transversely between the anterior borders 3f the tibia and fibula, and measuring about 2 inches from above downwards. Above and below it the deep fascia is exceedingly thin. The structures lying deeply to it are in order from within outwards: (1) tibialis anterior, (2) extensor hallueis longus, (3) anterior tibial vessels,

(4) anterior tibial nerve, (5) extensor digitorum longus, and (6) peroneus tertius. These structures occupy one common compartment, the tibialis anterior tendon alone being provided with a synovial sheath.

The inferior extensor retinaculum is a thicker and more defined structure than the superior. It is placed in front of the ankle-joint, and serves to strap down the extensor tendons and prevents them from springing forwards in a region where the direction of the tendons suddenly changes from a vertical disposition in the leg to a nearly horizontal one in the foot. The ligament therefore plays the part of a pulley. It may be likened to the capital letter Y (Fig. 364). The outer part, or stem of the Y, is a narrow band attached to a depression on the upper surface of the front part of the calcaneum. Its attachment is closely associated with that of the extensor digitorum brevis,


Fig. 364.—The Synovial Sheaths at the Ankle (Anterior View) (after L. Testut’s ' Anatomie Humaine ’)•













604


A MANUAL OF ANATOMY


some of the fibres of the muscle taking origin from it. This part i: disposed in the form of a loop or sling (fundiform ligament of Retzius) through which the tendons of the extensor digitorum longus anc peroneus tertius pass, the two being invested by one synovial sheath Its inner end is continuous with two diverging bands, an upper and c lower. The upper band is attached to the medial malleolus; th( anterior tibial vessels and nerve and the tendon of the extensor halluci* longus, surrounded by a synovial sheath, lie deeply to it. Farthei inwards it splits to enclose the tendon of the tibialis anterior, the layei of the ligament lying deeply to the tendon being the thicker. The tendon of the tibialis anterior is provided with a synovial sheath, which is prolonged upwards into the leg behind the superior extensoi retinaculum and downwards into the foot. The lower band is comparatively weak and arches across the foot to its inner side, where it is adherent deeply to the tuberosity of the navicular bone, and is continuous with the plantar aponeurosis. The dorsalis pedis vessels and anterior tibial nerve, together with the tendons of the extensor hallucis longus and tibialis anterior, each invested by its own synovial sheath, lie deeply to it.


The Inner Side of the Leg.

The inner surface of the tibia, except at its upper end, is subcutaneous. The deep fascia is here very thin, and is closely associated with the periosteum. The long saphenous vein lies about a finger’s breadth behind the medial border of the tibia, and receives many tributaries from the front and back of the leg. In the upper part of the leg it is accompanied by the saphenous branch of the descending genicular artery. The long saphenous nerve lies immediately behind it. The terminal branches of the medial cutaneous nerve supply the skin in the upper part of the inner aspect of the leg. Attached to the upper part of the inner surface of the tibia are the tendons of insertion of the sartorius, gracilis, and semitendinosus, and the medial ligament of the knee-joint. The tendons of the sartorius, gracilis, and semitendinosus, in this order from before backwards, pass obliquely downwards and forwards superficially to the medial ligament, from which they are separated b}^ a large bursa. Lying deeply to the medial ligament are the tendon of insertion of the semimembranosus, which is implanted into the horizontal groove on the medial tibial condyle, and at a lower level the inferior genicular artery.


The Front of the Leg.

I he musculo-cutaneous nerve is one of the two terminal branches of the lateral popliteal, and arises from that nerve as it lies on the outer side of the neck of the fibula deeply to the peroneus longus. It descends in the anterior fibular intermuscular septum, lying between the extensor digitorum longus in front and the peroneus longus and


THE LOWER LIMB


605


Drevis behind. In the lower part of the leg it becomes superficial, md divides into two terminal cutaneous branches, media] and ateral.

Branches.—Muscular to the peroneus longus and peroneus brevis; md cutaneous to the skin covering the lower third of the front of

he leg. The medial terminal branch descends to the dorsum of the foot, s superficial to both parts of the extensor retinaculum, and divides nto two branches, inner and outer. The inner branch supplies the


Fig. 365. —The Cutaneous Nerves and Dorsal Plexus of Veins on the Dorsum of the Foot.

skin on the inner side of the foot, communicates with the saphenous and anterior tibial nerves, and extends forward to supply the skin on the inner side of the great toe. The outer branch divides into two branches, which supply the skin lining the cleft between the second and third toes.

The lateral terminal branch also descends into the foot, and lies superficial to the extensor retinaculum. It divides into two branches, inner and outer. The inner branch subdivides and supplies the adjacent sides of the third and fourth toes; the outer has a similar distribution











6 o6


A MANUAL OF ANATOMY


to the fourth and fifth toes. The outer branch supplies the skin ( the outer side of the foot, and communicates with the sural nerve.


Ext. dig. longus


Ext. hall, longus


Peroneus tertius

Ant. perf. of peroneal artery

Ext. dig. brevis


Fig. 366. —Dorsal Aspect of Leg and Foot : Superficial Dissection of Muscles.


The nerve supplying the skin of t adjacent sides of the fourth and fifth to is variable. It is often a branch of t sural nerve, in which case the later terminal branch of the musculo-cutaneo is small and supplies the cleft betwei the third and fourth toes only.

Muscles—Tibialis Anterior (Fi< 366)— Origin. —The lower part < the lateral condyle of the tibk the upper two-thirds of the later; surface of the shaft of the tibia an the adjacent part of the interosseoi membrane; the deep fascia coverin it; and an intermuscular septui between it and the extensor dig torum longus.

Insertion. —The tendon extenc downwards on the inner side of th foot to a groove on the inner surfac of the medial cuneiform bone, wher it divides into two slips. The pos terior slip is inserted into an ovc impression at the lower part c the inner surface of the media cuneiform bone ; the anterior i inserted into the tuberosity on th plantar aspect of the base of th first metatarsal bone.

Nerve - supply. — The anterio tibial nerve.

Action. —Flexes the foot upoi the leg, and by raising its inne border inverts the foot.

Extensor Hallucis Longus— Origin. —The middle two-fourths of th( anterior surface of the shaft 0: the fibula, and the adjacent pari of the interosseous membrane.

Insertion .—The dorsal surface of the base of the distal phalanx of the great toe.


The extensor hallucis longus frequently gives an additional slip of insertior to the base of the proximal phalanx of the great toe.

Nerve-supply .—The anterior tibial nerve.

Action. Extends the distal phalanx of the great toe, and flexes the foot upon the leg.



















THE LOWER LIMB


607

The extensor hallucis longus is a very narrow muscle which lies leeply between the tibialis anterior and extensor digitorum longus. [t becomes superficial between the two in the lower part of the leg.

Extensor Digitorum Longus— Origin. —The lateral condyle of the

ibia; the upper three-fourths of the anterior surface of the shaft of the ibula; the interosseous membrane; the deep fascia covering it; and the ntermuscular septa between it and the adjacent muscles.

Insertion. —The intermediate and distal phalanges of the four Duter toes. As the tendons pass across the dorsal aspects of the netatarso-phalangeal joints they broaden into expansions which occupy

he dorsal aspects of the proximal phalanges and receive the tendons >f the lumbrical and interosseous muscles, and, in the case of the endons destined for the second, third, and fourth toes, by the tendons >f the extensor digitorum brevis. Towards the distal end of the proximal phalanx each tendon divides into three bands. The central Dand is inserted into the base of the intermediate phalanx. The two ateral bands converge, and, having united, are inserted into the dorsal aspect of the base of the distal phalanx.

Nerve-supply. —The anterior tibial nerve.

Action. —Extends the intermediate and distal phalanges of the four auter toes, and flexes the foot upon the leg.

Peroneus Tertius— Origin. —Its muscular belly is inseparable from that of the extensor digitorum, of which it may be regarded as the iower part; it is consequently attached to the lower part of the anterior surface of the fibula and the adjoining part of the interosseous membrane.

Insertion. —It ends in a tendon which is inserted into the base of the fifth metatarsal bone.

N erv e-supply. —The anterior tibial nerve.

Action. —Flexes the foot upon the leg, and by raising its outer border averts the foot.

The peroneus tertius is a very variable muscle, and is not infrequently absent, it is a muscle peculiar to man, and is a detached slip from the extensor digitorum fongus, with which its belly is more or less confluent. It is essentially a muscle associated with the erect posture, everting the foot and bringing it into the plantigrade position, where the sole is directly applied to the ground. Its tendon may be inserted at any point from the distal to the proximal end of the fifth metatarsal, and occasionally ends in a fan-shaped expansion which is attached for nearly the whole length of the shaft of the bone.

The anterior tibial artery is one of the two terminal branches of the popliteal artery. It commences at the lower border of the popliteus muscle on a level with the lower border of the tubercle of the tibia (fully 1J inches below the level of the upper surface of the head of that bone), and ends in front of the bend of the ankle, midway between the two malleoli, where it is continuous with the dorsalis pedis artery. At its commencement it is placed on the back of the leg, and thence passes forwards between the two heads of the tibialis posterior, and through a deficiency in the upper part of the interosseous membrane,


6 o8


A MANUAL OF ANATOMY


where it lies below the superior tibio-fibular joint. Having reachec the front of the leg, the course of the vessel changes somewhat abruptly and it descends in close contact with and in front of the interosseous membrane until it reaches the junction of the upper two-thirds anc lower third of the leg. Below this level it inclines inwards on to the front of the tibia, upon which it lies for the rest of its course. The course of the vessel on the anterior aspect of the leg corresponds witf

a line drawn from the superioi


Recurrent Genicular Nerve

■ Lat. Popliteal Nerve - - - Musculo-cutaneous N. Anterior Tibial Nerve


Interosseous Membrane '


Tibialis

Anterior


Peroneus Tertius


Anterior Tibial Artery and Nerve


Extensor Hallucis Longus


. Extensor Digitorum Longus


_Musculo-cutaneous N.

(Cutaneous Portion)


I-Peroneus Brevis


_Peroneus Longus


Fig. 367. —The Front of the Left Leg (Deep Dissection).


tibio-fibular joint to a poinl on the front of the ankle midway between the twe malleoli.

Relations —On the Back oj the Leg. — The artery lies deeply to the gastrocnemius and between the two heads of the tibialis posterior, the lower border of the popliteus muscle being directly above it.

On the Front of the Leg — Superficial. — In the uppei three-fourths the artery is deeply placed, being overlapped by the adjoining edges of the tibialis anterior on the inner side and the extensor digitorum longus and extensor hallucis longus on the outer side. In the lower part of the leg, where the muscles are to a large extent replaced by tendons, the vessel is comparatively superficial. It is covered in front by the extensor retinacula and the extensor hallucis longus, which crosses it from without inwards at some little distance above the ankle-joint. Deep .—The interosseous membrane, the


anterior surface of the tibia in its lower fourth, and the anterior ligament of the ankle-joint. Lateral .—Extensor digitorum longus in the upper part of the leg, the extensor hallucis longus at a lower level, and the extensor digitorum longus again for a short distance above the ankle. Medial .—Tibialis anterior for the greater part of its extent, and the extensor hallucis longus at the lower end of the leg.


















THE LOWER LIMB


609


It is accompanied by two venae comites, between which are umerous transverse communications lying in front of the artery, 'he two venae comites pass backwards through the upper part of the nterosseous membrane, and join the venae comites of the posteripr ibial artery to form the popliteal vein.

In the upper fourth of the leg the anterior tibial artery is separated rom the anterior tibial nerve by the extensor digitorum longus. The nterior tibial nerve, which gains the front of the limb by winding round he outer side of the neck of the fibula, passes through the upper part f the extensor digitorum longus obliquely, and comes into contact nth the artery, with which it descends on the front of the interosseous aembrane. The nerve is at first to the outer side of the artery, then les in front of it, and reverts to its outer side again in the lower part if the leg.

Branches. —In addition to cutaneous branches and muscular tranches which supply the muscles on the front of the leg, and also >ass backwards through the interosseous membrane to supply the ibialis posterior, the anterior tibial artery gives off the following >ranches:

The posterior tibial recurrent artery is inconstant. It arises from he commencement of the anterior tibial artery on the back of the eg. It passes upwards deeply to the popliteus muscle, to which it is listributed, as well as to the posterior ligament of the knee-joint. It .nastomoses with inferior genicular branches of the popliteal artery.

The circumflex fibular artery also arises from the anterior tibial m the back of the leg. It winds round the neck of the fibula, and is listributed to the peroneus longus, the superior tibio-fibular joint, aid the skin.

The anterior tibial recurrent artery arises from the anterior tibial >n the front of the leg. It passes upwards in company with the reurrent genicular branch of the lateral popliteal nerve through the ipper part of the tibialis anterior, to which it is distributed, and ends >y anastomosing with the inferior genicular branches of the popliteal irtery.

The medial anterior malleolar artery is a small branch which arises rom the inner side of the anterior tibial near the lower end of the leg. t passes inwards deeply to the tendon of the tibialis anterior, and amifies over the medial malleolus, where it anastomoses with the orresponding branch of the posterior tibial artery and the tarsal ranches of the dorsalis pedis.

The lateral anterior malleolar artery arises from the outer side of the interior tibial at a slightly lower level than the medial. It passes nitwards deeply to the tendons of the extensor digitorum longus and xroneus tertius, and ramifies over the lateral malleolus, where it mastomoses with the anterior peroneal, the posterior peroneal, and the lateral tarsal branches of the dorsalis pedis.

Varieties—1. Origin. —The vessel may arise from the popliteal at the upper border of the popliteus muscle. In such cases it may descend on the posterior

39


610 A MANUAL OF ANATOMY

surface of that muscle (this being the more frequent position), or it may pa; deeply to it.

2. Course. —The vessel in the lower fourth of the leg may be found upo the fibula instead of the tibia, in which cases it makes a sudden bend at th ankle-joint to become continuous with the dorsalis pedis artery. In very rai cases the vessel may become superficial in the middle of the leg.

3. Size. —The vessel is occasionally very small, and if the diminution i size is very pronounced, it may fail to furnish the dorsalis pedis artery, in whic cases that vessel is supplied by the peroneal.

The peroneal artery reaches the front of the leg by passing througj the lower part of the interosseous membrane, and descends in front c the inferior tibio-fibular joint tying deeply to the peroneus tertius. I ends by anastomosing with the lateral anterior malleolar artery, th tarsal branches of the dorsalis pedis, and the peroneal.

The anterior tibial nerve is one of the two terminal branches of th lateral popliteal. It commences upon the outer side of the neck of th fibula, where it lies between the bone and the peroneus longus, extend downwards to the ankle, and ends by dividing into two termina branches. It passes through the upper end of the extensor digitorun longus, and then descends with and has the same general relations a the anterior tibial artery. Its relations to the artery have already beei described.

The branches are muscular and articular. The muscular branche supply the tibialis anterior, extensor digitorum longus, extensor halluci longus, and peroneus tertius. The articular branches arise from thi lower part of the nerve, and are distributed to the ankle and inferio: tibio-fibular joints.

The nerve to the peroneus tertius is the terminal twig of a branch of thi anterior tibial given ofi in the upper part of the leg. This branch passes througl the substance of the extensor digitorum longus, which it supplies, and ends ir the peroneus tertius.

The anterior tibial lymphatic gland is situated in front of the uppei part of the interosseous membrane close to the anterior tibial artery Its afferent vessels convey lymph from the deeper parts of the dorsun of the foot and front of the leg. The efferent vessels pass backwards with the anterior tibial artery through the interosseous membrane and join the popliteal glands.

Dorsum of the Foot.

Superficial Fascia. —Embedded in the superficial fascia are the cutaneous nerves and the dorsal plexus of veins.

The dorsal plexus of veins is a network of veins embedded in the subcutaneous tissue. The arrangement is very variable, but the plexus is usually disposed in the form of an arcade occupying the metatarsal region, and with its convexity towards the toes. The plexus receives many tributaries coming from the plantar aspect of the foot, from the dorsum, and from the toes. Most of the blood distributed to the toes by the digital arteries is returned to the dorsal


THE LOWER LIMB


6 n


>lexus. The inner side of the plexus is drained by the long saphenous rein, which passes upwards in front of the medial malleolus; the outer ide by the short saphenous vein, which passes upwards behind the ateral malleolus.

The deep fascia is a thin membranous layer continuous with the xtensor retinacula, and covering the long extensor tendons supericially. Another layer of deep fascia lies deeply to the extensor tendons, nd covers the extensor digitorum brevis; a third layer on a still deeper >lane invests the dorsal interosseous muscles and the dorsal surfaces >f the metatarsal bones.

Extensor Digitorum Brevis (Fig. 369)— Origin .—'The front part of he upper surface and the adjacent part of the lateral surface of the alcaneum, and the stem of the inferior extensor retinaculum.

Insertion. —The four inner toes by means of four tendons; the nnermost tendon has an independent insertion into the base of the >roximal phalanx of the great toe. The other three tendons join the iuter borders of the long extensor tendons passing to the second, third, nd fourth toes, the junctions taking place opposite the metatarso>halangeal joints.

Nerve-supply .—The lateral terminal branch of the anterior tibial ierve.

Action. —The innermost tendon extends the great toe at the metaarso-phalangeal joint, and also acts as an adductor. The second, hird, and fourth tendons extend the corresponding toes in conjunction vith the long extensor tendons. In so doing they tend, by the obliquity •f their direction, to draw the toes outwards, and in this way they teutralize the effect of the long extensor tendons, which are so disposed .s to draw the toes inwards.

The muscle lies obliquely on the dorsum of the foot, being directed orwards and inwards. The innermost fleshy bundle is more or less adependent of the rest of the muscle, and is sometimes regarded as an ^dependent muscle, called the extensor hallucis brevis.

The dorsalis pedis artery (Fig. 368) is the continuation of the anterior ibial artery, and commences at the bend of the ankle, midway between he two malleoli. It ends at the proximal end of the first intermetaarsal space, where it divides into two branches, the deep plantar or •erforating, and the arteria dorsalis hallucis or first dorsal metatarsal rtery. The course of the vessel is indicated by a line drawn from a 'oint on the front of the ankle, midway between the two malleoli, to he proximal end of the first interosseous space.

Relations. —The artery is covered superficially by the inferior xtensor retinaculum, fascial layers and the innermost tendon of the xtensor digitorum brevis. It lies on the talus, navicular, intermediate uneiform, base of second metatarsal, and the ligaments connecting hese bones together. It lies for the most part between the tendons of he extensor digitorum longus on its outer side and that of the extensor allucis longus on its inner side. Close to its termination it is crossed uperficially by the tendon of the extensor brevis hallucis, which passes


612


A MANUAL OF ANATOMY


from its outer to its inner side. The medial terminal branch of tt anterior tibia! nerve (dorsalis pedis nerve) lies to its outer side. It accompanied by two venae comites. The artery is very superficial, £ the only structures which separate it from the surface are, with tt exception of the tendon of the extensor hallucis brevis, fascial layei and skin.


Fig. 368.—The Arteries on the Dorsum of the Right Foot (after L. Testut’s ‘ Anatomie Humaine ’).


Branches. —The tarsal arteries, two or three in number, supply tin structures on the inner border of the foot, where they anastomose witl branches of the medial plantar artery.

A lateral branch passes outwards deeply to the extensor brevis digi torum, which it supplies; it is also distributed to the tarsal joints anc the skin. It anastomoses with the lateral anterior malleolar, tht arcuate, and lateral plantar arteries.

The arcuate (metatarsal) artery arises close to the proximal end 0: the first intermetatarsal space, and passes outwards to the outer bordei of the foot, crossing the bases of the metatarsal bones, and lying deeply.










THE LOWER LIMB


613


to the extensor digitorum brevis. It anastomoses with the tarsal and lateral plantar arteries. The vessel forms a slight arch, with the

onvexity directed forwards. From the concavity of the arch a few recurrent branches pass backwards to the tarsal joints. From the convexity three dorsal metatarsal arteries pass forwards and occupy the three outer intermetatarsal spaces. At the level of the metatarsophalangeal joints each divides into two dorsal digital arteries, which supply the adjacent sides of the second and third, third and fourth.


Peroneus Brevis Peroneus Longus


Extensor Digitorum Longus Lat. Malleolar Anastomosis


Peroneus Tertius


Metatarsal Artery


Musculo-cutaneous Nerve


_Superior Extensor Retinaculum

... Extensor Hallucis Longus ....Tibialis Anterior


Inferior Extensor Retinaculum


Lateral Branch of Dorsalis Pedis Nerve

Extensor Digitorum Brevis Medial Tarsal Branches

Medial Branch of Anterior Tibial Nerve Dorsalis Pedis Artery


Communicating Branch between Musculo-cutaneous and Anterior Tibial Nerves


. First Dorsal Metatarsal Artery


Fig. 369.—Dissection of the Dorsum of the Right Foot.


and fourth and fifth toes. The most lateral dorsal metatarsal artery also supplies a branch to the outer side of the little toe. At the proximal ends of the second, third, and fourth intermetatarsal spaces each of the three dorsal metatarsal arteries is joined by a perforating artery from the plantar arch.

The first dorsal metatarsal artery (arteria dorsalis hallucis) arises from the terminal part of the dorsalis pedis, and, continuing the direction of that vessel, passes forwards to the first intermetatarsal space. On

















A MANUAL OF ANATOMY


614

reaching the cleft between the great and second toes it divides int< two dorsal digital branches supplying the adjacent sides of these tw( toes; it also gives a branch to the inner side of the great toe.

The dorsal digital arteries as they pass along the sides of the toe: communicate with each other across their dorsal aspects, and also witf the corresponding plantar digital arteries.

The deep plantar or perforating branch is to be regarded as the con tinuation of the dorsalis pedis artery. It passes downwards into th< sole at the proximal end of the first intermetatarsal space. In the sob it completes the plantar arch by joining the lateral plantar artery.

Varieties of the Dorsalis Pedis Artery—1. Origin. —The vessel may be the con

tinuation of the peroneal artery.

2. Course. —The vessel often describes a considerable curve outwards befori reaching the proximal end of the first intermetatarsal space. In these case: the artery may end at the proximal end of the second intermetatarsal spac< instead of at the first.

3. Branches. —These are very variable, especially the arcuate artery. Thi: may arise in common with the tarsal branch. The arcuate arch is often ver^ indefinite. The arcuate artery is sometimes absent, and when this occurs th< dorsal metatarsal arteries of "the three outer spaces are usually furnished b} the three perforating arteries from the plantar arch, or in some cases by th< tarsal artery.

The Terminal Branches of the Anterior Tibial Nerve. —The anterioi tibial nerve ends at the bend of the ankle by dividing into two branches lateral and medial.

The lateral branch is the shorter, and is distinguished by having a swelling or pseudo-ganglion upon it. It descends on to the dorsun of the foot, where it lies on the deep aspect of the extensor digitorun brevis, to which it is distributed. It ends in branches supplying the tarsal joints, and in two or three very slender interosseous branches which extend forwards on the dorsal interosseous muscles and suppl} the tarso-metatarsal and metatarso-phalangeal joints; one of them is said to supply the second dorsal interosseous muscle.

The medial branch, or dorsalis pedis nerve, extends forwards or the dorsum of the foot, accompanying and having the same genera relations as the dorsalis pedis artery, on the outer side of which it lies It ends by dividing into two branches, which supply the skin of the adjacent sides of the great and second toes. It gives a metatarsa branch, which occupies the first intermetatarsal space and supplies the tarso-metatarsal and metatarso-phalangeal joints of the great toe as well as the first dorsal interosseous muscle.

The nerves derived from the anterior tibial and supplying the first anc second dorsal interosseous muscles are probably sensory and do not contair motor fibres.


The Outer Side of the Leg.

The skin on the outer side of the leg is supplied by the latera] cutaneous nerve of calf and branches from the short external saphenous nerve.


THE LOWER LIMB


615


The sural nerve (Fig. 329), from the medial popliteal, receives the sural communicating branch of the lateral popliteal nerve at, or just below, the middle of the calf. The nerve descends on the outer side of the short saphenous vein, and lateral to the tendo-calcaneus. It passes behind and below the lateral malleolus, and thus reaches the outer border of the root, along which it passes to the outer side of the little toe. The nerve supplies the skin on the back and outer side of the leg in its lower half, the outer side of the foot, and the outer side of the little toe. It also furnishes articular branches to the ankle and talo-calcaneal joints.

The short saphenous vein drains the outer side of the plexus of veins on the dorsum of the foot, and passes upwards from the foot behind the lateral malleolus, and thus reaches the back of the leg. In the lower part of the leg it lies to the outer side of the tendo-calcaneus, but inclining upwards and inwards it gains the middle line of the calf, and ascends in the groove between the two heads of the gastrocnemius. At the lower angle of the popliteal fossa it traverses the deep fascia, and ends by joining the popliteal vein. In the lower part of its course it is accompanied, on its outer side, by the sural nerve. In the groove between the two heads of the gastrocnemius it is accompanied by the terminal part of the posterior cutaneous nerve of the thigh, the sural cutaneous artery, and superficial lymphatic vessels which' join the popliteal glands. In addition to draining the dorsal plexus, it receives numerous tributaries from the outer and back parts of the leg. At its termination it is usually joined by a vein descending from the back of the thigh, and by a fairly constant communicating vein which ascends to join the long saphenous vein. It communicates with the deep veins behind the lateral malleolus, and at intervals along the back of the leg. The short saphenous vein is provided with ten to twelve valves.

The termination of the short saphenous vein is very variable. Instead of joining' the popliteal vein, it may ascend in the roof of the popliteal fossa, wind round the inner side of the lower part of the thigh, and end in the long saphenous vein; or it may ascend more deeply, accompany the medial popliteal nerve, and join the lowest perforating vein or one of its tributaries.

Muscles—Peroneus Longus (Fig. 371)— Origin .—The anterior aspect of the head of the fibula and the adjacent parts of the lateral


Short Saphenous Long Saphenous


Fig. 370.—The Short Saphenous Vein and its Tributaries.








6 i6


A MANUAL OF ANATOMY


condyle of the tibia; the upper two-thirds of the lateral surface of the shaft of the fibula; the two fibular intermuscular septa and the deep fascia.

Insertion .—The tendon of insertion divides into two slips. The larger is inserted into the outer side of the tuberosity on the plantar surface of the base of the first metatarsal bone, and the smaller into


Lateral Popliteal Nerve .—


Tendon of


Gastrocnemius.


Soleus,


Peroneus Longus Peroneus Brevis


Tendo Calcaneus


Lateral Ligament of Knee-J oint


Extensor Hallucis Longus Extensor Digitorum Longus Peroneus Tertius

Superior Extensor Retinaculum

Inferior Extensor Retinaculum Extensor Digitorum Brevis Tendon of Peroneus Tertius


Fig. 371.—Muscles of the Leg (Lateral Aspect).


the lower and anterior part of the outer surface of the medial cuneiform bone.

Nerve-supply .—The musculo-cutaneous nerve.

Action .—Extends the foot upon the leg; abducts the front part of the foot— i.e., turns it outwards; everts the foot bv raising its outer border.

The tendon descends behind that of the peroneus brevis, and with it occupies the groove behind the lateral malleolus deeply to the peroneal



















THE LOWER LIMB


617

retinaculum, the two tendons having a common synovial sheath. Below the malleolus the tendon passes forwards and downwards on the outer surface of the calcaneum, where it occupies the groove below the peroneal tubercle. In this part of its course the tendon is surrounded by a fibrous sheath, which is derived from the lower part of the peroneal retinaculum, and is invested by an independent synovial sheath, which is a prolongation of the common sheath behind the lateral malleolus. It winds round the outer border of the foot, and then crosses the sole from without inwards, being lodged in the groove on the plantar surface of the cuboid. This groove is converted into a fibro-osseous canal by the long plantar ligament, and is lined by a synovial sheath. Embedded in the tendon as it winds round the cuboid is a sesamoid cartilage which may ossify.

Peroneus Brevis (Fig. 371)— Origin .—The lower two-thirds of the lateral surface of the shaft of the fibula, the two fibular intermuscular septa, and the deep fascia.

Insertion .—The tuberosity on the outer side of the base of the fifth metatarsal bone. A slip from the tendon of insertion is occasionally given to the long extensor tendon of the little toe.

Nerve-supply .—The musculo-cutaneous nerve.

Action .—Extends the foot and everts the foot by raising its outer border.

The middle third of the lateral surface of the fibula is occupied by both peroneus longus and peroneus brevis, the former arising from the posterior half, and the latter from the anterior half; the two muscles consequently overlap. The tendon of the peroneus brevis occupies the groove behind the lateral malleolus, the tendon of the peroneus longus being directly behind it. Both tendons lie deeply to the peroneal retinaculum, and are invested by a common synovial sheath. Below the lateral malleolus the tendon of the peroneus brevis passes downwards and forwards on the outer surface of the calcaneum, where it occupies the groove above the peroneal tubercle. The tendon is here surrounded by a fibrous sheath derived from the peroneal retinaculum, and is invested by a distinct synovial sheath continuous with the common sheath above. From the os calcis the tendon passes forwards on the cuboid bone to reach its insertion.

On the outer surface of the os calcis the two peroneal tendons are separated from each other by the peroneal tubercle, the tendon of the peroneus longus being below that of the peroneus brevis.

The Back of the Leg.

Muscles. —The muscles of the back of the leg are divided into two groups—superficial and deep.

Superficial Group .—The muscles of this group are the gastrocnemius, soleus, and plantaris, and are known as the sural or calf muscles.

Gastrocnemius — Origin .—The outer head, the shorter and thinner, arises mainly by tendon, but partly by muscle fibres from a depression


6 i8


A MANUAL OF ANATOMY


on the outer aspect of the lateral femoral condyle (immediately abo the most projecting point of the lateral epicondyle which gives attac ment to the lateral ligament of knee-joint) and from the lower end

the lateral supracondylar lir


Gracilis—


Semi-memb.


Semi-tend..


Biceps


Plantaris Peron. N.


\ \\l


Gastrocnemius.


.Soleus.


Calcanean

Tendon


Peronei


Medial

Malleolus


F. Hall. Long.


The tendon is adherent the posterior ligament of t] knee-joint, and at the se of adherence usually contai: a sesamoid cartilage whi< may ossify.

The inner head, the long and thicker, arises by tench from an impression above tl posterior surface of the medi femoral condyle, abuttir upon the lower end of tl medial supracondylar lin and extending downwart and inwards to the adduct* tubercle.

Insertion .—The fleshy pa of the muscle ends in a fk tendon, which commences i an aponeurotic sheet on tl deep surface of the muscl and, in the lower part of tl leg, joins the more deeph placed tendon of the solei to form the tendo-calcaneu


The gastrocnemius is inserte


V


by means of this commc tendon into a rough impre: sion on the lower part of tf posterior surface of the ca caneus; a bursa intervem between the tendon and th upper smooth part of th surface.

Nerve-supply. — The m< dial popliteal nerve, whic furnishes two branches, or for each head.

Action .—The muscle is powerful extensor of the foot upon the leg and raises the heel. If tl ankle-joint is fixed it can flex the knee-joint.

The two heads of the muscle converge, and together form the later; boundaries of the lower part of the popliteal fossa. Below the low* angle of the popliteal fossa the junction of the two heads is represente


Fig. 372.—Superficial Aspect ofMuscles of Calf.















THE LOWER LIMB


619


iperficially by a longitudinal groove, on the floor of which is a mdinous band or raphe. The muscular fibres of the gastrocnemius re all relatively very short, and extend obliquely from two tendons f origin to a tendon of insertion. The two tendons of origin spread at into aponeurotic sheets, and partially cover the two heads of the mscle superficially. The tendon of insertion commences as an poneurotic sheet which covers the deep or anterior aspect of the mscle for nearly its whole extent, and narrows below into the tendon hich takes part in the formation of the tendo-calcaneus.

Lying deeply to the medial head at the back of the knee, and also itervening between it and the semimembranosus, is one of the largest nd most important bursae in the neighbourhood of the joint. This ursa is usually continuous with the synovial membrane of the joint irough a deficiency in the capsular ligament.

Soleus (Fig. 371)— Origin .—The posterior surface of the head and tie upper third of the posterior surface of the shaft of the fibula; fibrous arcade attached on either side to the fibula and tibia and rching over the popliteal vessels and nerve; the soleal (popliteal) line f the tibia, from the lower of which it extends downwards on to the iternal border of the tibia for about its middle third; the posterior bular intermuscular septum.

Insertion .—The tendon, which is continuous with an extensive poneurosis coating the superficial surface of the muscle, joins that f the gastrocnemius to form the tendo-calcaneus.

Nerve-supply .—The medial popliteal nerve, the branch from which nters the muscle on its superficial surface near the upper border; and branch from the posterior tibial nerve, entering the muscle on its eep or anterior surface near the middle of the leg.

Action .—The muscle is a powerful extensor of the foot, and with he gastrocnemius is concerned in raising the heel.

The muscle fibres are short and oblique; they are attached to bone 0 a limited extent only. Most of the fibres arise from two tendinous •lanes which extend downwards into the substance of the muscle, ne from the fibula and the other from the soleal line of the tibia, and he fibrous arcade arching over the popliteal vessels. These two planes xtend downwards into the substance of the deep part of the muscle, nd are obliquely disposed in such a way that when seen in section hey converge towards the superficial surface of the muscle. The bres arising from the anterior surfaces of these two tendinous planes erminate upon a median tendinous band which projects into the fiddle of the muscle from its deep aspect; those arising from the •osterior surfaces end upon a broad expanded aponeurosis, which overs the posterior or superficial surface of the muscle. In the lower >art of the leg the median tendinous band blends with the aponeurosis overing the superficial aspect of the muscle to form the tendon of nsertion, which joins that of the gastrocnemius to form the tendoalcaneus.

The tendo-calcaneus (Achillis) results from the junction of the


620


A MANUAL OF ANATOMY


tendons of the gastrocnemius and soleus. It is at first broad and cor paratively thin. As it descends it becomes narrower and thicker uni it reaches a point about i\ inches above the calcaneus, below which again broadens to its insertion. The short saphenous vein and nen lie on its outer side, the tendon of the plantaris and the posterior tibi vessels and nerve on its inner side; there is a large mass of fat on i deep aspect.

The fibres of the gastrocnemius and soleus are so arranged that both the muscles can exert an exceedingly strong pull through a relatively short distanc Together they form one of the most powerful muscular combinations in tj body, of such strength that, when standing on one leg, the heel can be easi raised from the ground, thereby lifting the whole weight of the body on to t toes, by the contraction of the muscles of one limb only.


D


Fig. 373. —A Semidiagrammatic Horizontal Section through the Soleus to illustrate the Arrangement of the Muscle Fibres.

A and B, the two intramuscular tendons of origin arising from the tibia an fibula; C, the intramuscular tendon of insertion, which below joins D, tl aponeurosis on the surface of the muscle, to form the main tendon.

Plantaris — Origin .—The lower part of the lateral supracondyk line of the femur, medial to, and to a slight extent above, the later; head of the gastrocnemius. The lowest fibres are attached to th posterior ligament of the knee-joint.

Insertion .—The posterior surface of the os calcis to the inner sid of the tendo-calcaneus.

Its insertion is somewhat variable, as it may end in the tendo calcaneus, th deep fascia of the leg, the flexor retinaculum, or the plantar aponeurosis.

Nerve-supply .—The medial popliteal nerve.

Action .—The plantaris is a very weak extensor of the foot, and i a feeble auxiliary to the gastrocnemius.

The fleshy belly is very short. The tendon, very narrow and th longest in the body, descends obliquely downwards and inwards be tween the gastrocnemius superficially and the soleus deeply.






THE LOWER LIMB


621


The plantaris is very variable and is sometimes absent. It is a vestigial uscle, and represents the flexor of the proximal phalanges of the toes, a muscle -esent in quadrupeds. The foot portion of the tendon, from which it has jcome separated by the calcaneum, persists as the central part of the plantar >oneurosis. The plantaris is the counterpart of the palmaris longus in the upper nb.

Deep Group. —The muscles in this group are the popliteus, flexor igitorum longus, tibialis posterior, and flexor hallucis longus. The opliteus is a small muscle confined to the region of the knee, and is )vered by an expansion derived from the tendon of the semimemranosus. The other three muscles are situated below the popliteus, nd are covered by the transverse intermuscular septum.

Popliteus — Origin. —By a narrow rounded tendon from a pit which larks the front limit of the popliteal groove on the outer surface of le lateral condyle of the femur.

Insertion. —The inner part of a triangular area occupying the upper art of the posterior surface of the tibia, and limited below by the Dleal line. Some of its superficial fibres are adherent to the tendinous xpansion which covers the posterior surface of the muscle.

Nerve-supply. —A branch of the medial popliteal nerve, which escends on the posterior surface of the muscle, and, winding round

s lower edge, finally ascends to enter its deep or anterior surface. Action. —The muscle is a feeble flexor of the knee-joint; it also otates the leg inwards on the thigh.

The tendon of origin winds round the outer side of the knee-joint, /here it is within the limits of the capsular ligament, and lies deeply to he lateral ligament, superficial to which is the tendon of the biceps, t is in contact with the posterior and outer aspect of the lateral semiunar cartilage, upon which it impresses a groove. It escapes from he posterior part of the capsule, and, becoming replaced by muscle ibres, spreads out in a fan-like manner on to the back of the tibia.

Flexor Digitorum Longus — Origin. —The inner part of the posterior .urface of the shaft of the tibia, extending downwards from the soleal ine above for about the middle two-fourths of the bone; the transverse ntermuscular septum; and a septum between it and the tibialis posterior.

Insertion. —By four tendons attached to the four outer toes; each

endon is inserted into the plantar surface of the base of the distal ohalanx.

Nerve-supply . —The posterior tibial nerve.

Action. —Flexes the distal phalanges of the four outer toes, and extends the foot on the leg.

The muscle crosses the tibialis posterior superficially, being to the Lnner side of this muscle above and to its outer side below. The tendon passes behind the medial malleolus, where it lies deeply to the flexor retinaculum, and external to the tendon of the tibialis posterior. It occupies a fibrous canal, in which it is invested by a distinct synovial sheath. From behind the medial malleolus it passes downwards and forwards, and thus gains the sole of the foot, where it inclines forwards


622


A MANUAL OF ANATOMY


and outwards, and crosses the tendon of the flexor hallucis longus, fro which it receives a slip, superficially. After crossing the flexor hallu< iongus it receives the attachment of the flexor accessorius, and divid Into four tendons, which, after having given origin to the four lumbric muscles, are prolonged on to the four outer toes. On the toe ea<

tendon has a tendon


Semi-membrane


Soleus


F. Dig. Long.


F. D. L.


T. P.


Flexor Retin.


-Biceps


.Soleus


Peroneal A.


.Peroneal M.


F. Hall. Long.


Tibialis Post.


Commun. Artery


— Peron. A.


Fig. 374 - —The Back cf the Leg, exposing Deep Muscles, etc., after Removal of Superficial Flexors.


the flexor digitorum bre^ lying superficially to the two tendons being co tained in a fibro-osseo canal lined by a synovi sheath. On the proxim phalanx the tendon of tl flexor brevis splits to gi 1 passage to the tendon the flexor longus; the fibr osseous canals and the synovial membranes, wii the vincula of the latt —namely, vincula brev and vincula longa—corr spond with those of tl fingers, the dispositions < the tendons, the fibr< osseous canals, the syn< vial sheaths and their vii cula being similar to tho< which are found in tl fingers (p. 491).

Tibialis Posterior — Or gin .—The outer part ( the posterior surface ( the shaft of the tibia, e:? tending upwards to th soleal line and downward to about the middle c the bone; the posteric surface of the interosseou membrane ; the medk


surface of the shaft of the fibula; the transverse intermuscular septur and the septa intervening between it and the flexor digitorum long 1 medially and the flexor hallucis longus laterally.

Insertion. The tuberosity of the navicular bone. From the ma: insertion into the tuberosity of the navicular bone tendinous slij spread out in various directions on the plantar aspect of the tarsu One passes backwards and is attached to the sustentaculum tali of tl calcaneum, one passes outwards to the cuboid, one passes forwarc to the medial cuneiform, while several slips pass forwards and outwarc















THE LOWER LIMB


623

1 to the intermediate and lateral cuneiforms, from which the)' are rolonged on to the bases of the second, third, and fourth metatarsal Dnes. The latter cross the tendon of the ^roneus longus superficially, and help to comlete the fibro-osseous canal in which it is mtained.

Nerve-supply .—The posterior tibial nerve.

Action .—Inverts the foot, and is an extensor [ the foot, upon the leg. Owing to its extenve attachments on the plantar aspect of the irsus and metatarsus, it braces up and accenlates the arches of the foot.

In the lower third of the leg the muscle rosses the deep aspect of the flexor digitorum >ngus obliquely, passing from its outer to its mer side. The tendon occupies the groove ehind the medial malleolus, where it is covered iperficially by the flexor retinaculum, and

contained in a fibro-osseous canal, with the mdon of the flexor digitorum longus lying iteral to it. It is invested here with a synovial leath, which follows it to its insertion on the avicular bone. In the foot it passes forwards elow the head of the talus, which it helps to ipport, and here contains a sesamoid cartiige. At the back of the leg the muscle is artially overlapped on either side by the flexor allucis longus and the flexor digitorum longus. overing its posterior surface is a dense fascial tyer, which is attached on either side to the bia and fibula.

Flexor Hallucis Longus — Origin .—The lower vo-thirds of the posterior surface of the shaft f the fibula—this surface winds on to the inner spect of the bone in the lower part of the leg; ie posterior fibular intermuscular septum; a upturn between it and the tibialis posterior, nd the transverse intermuscular septum.

Insertion .—The plantar surface of the base f the distal phalanx of the great toe.

N erv e-supply .—The posterior tibial nerve.

Action .—Flexes the distal phalanx of the feat toe. It also helps to maintain the longitudinal arch of the foot, and is to a certain ex'nt an auxiliary of the flexor digitorum longus,

} which it is fastened by a tendinous slip.

The tendon occupies a groove on the back of the lower end of ie tibia, which is converted into a fibro-osseous canal by the flexor


Fig. 375. —Plan to show the Changing Relations BETWEEN THE Main Artery and Nerve on the Back of the Lower Limb.






A MANUAL OF ANATOMY


624

retinaculum, and within which the tendon is provided with a synovi; sheath. Below the tibia the tendon occupies successively the groove on the posterior aspect of the talus, and on the under surface of th sustentaculum tali of the calcaneum. These grooves are converte by a fibrous roof into a fibro-osseous canal, in which the tendon i surrounded by a synovial sheath. In the sole the tendon is crosse superficially, and from within outwards, by that of the flexor digitorur longus, to which it is fastened by a tendinous slip. In most cases th fibres of this slip are prolonged into the flexor tendons of the secon and third toes (Turner).

In some cases the tendinous slip extends from the tendon of the flexor digitorui longus into that of the flexor hallucis longus.

The posterior tibial artery (Fig. 376) is the larger of the two terming branches of the popliteal. It commences at the lower border of th popliteus muscle on a level with the lower limit of the tubercle of th tibia, and usually ends deeply to the flexor retinaculum by dividin into the medial and lateral plantar arteries.

The level at which the artery divides into the two plantar arteries i variable.

In the upper two-thirds of the leg it is deeply placed, being situate* between the superficial and deep muscles, opposite to the interva between the tibia and fibula. It inclines downwards and inwards and in the lower third of the leg it becomes superficial, lying on th back of the tibia to the inner side of the tendo-calcaneus. The cours< of the vessel may be indicated by drawing a line from the middle of th< back of the leg at the lower angle of the popliteal fossa to a poin midway between the projection of the heel and the tip of the media malleolus.

Relations. —In the upper two-thirds the vessel is covered super ficially by the soleus, and is embedded in the transverse intermuscula: septum; in the lower third it is covered by the skin, superficial fascia and the flexor retinaculum. Lying deeply to it are the tibialis posterior the flexor digitorum longus, the posterior surface of the tibia, and th* medial ligament of the ankle-joint (in this order from above downwards) In the lower part of the leg the tendo-calcaneus is lateral to it. Undei cover of the flexor retinaculum the artery and its two venae comites together with the posterior tibial nerve on its outer side, are lodgec in a fibro-osseous canal. Here the tendons of the tibialis posterior anc flexor digitorum longus are on its inner side and the tendon of th* flexor hallucis longus on its outer side.

The artery is accompanied by two venae comites, which are connected together by numerous transverse communications lying super ficially to the artery, and which, at the lower border of the popliteus join the venae comites of the anterior tibial artery to form the poplitea. vein. Above the posterior tibial nerve is medial to the artery, but crossing the vessel superficially just below the origin of the peroneal


THE LOWER LIMB


625


ft

irtery, the nerve lies on its outer side for the rest of its course. Deeply

o the flexor retinaculum the artery has usually a nerve on either side

Medial Superior Genicular Artery- .-1


Medial Head of Gastrocnemius.— _ Medial Inferior Genicular Artery—


Popliteus- Posterior Tibial Nerve Nutrient Artery of Tibia Soleus (cut)

Tibialis Posterior. . _


-\_ Medial Popliteal Nerve

--.Popliteal Artery


Flexor Digitorum Longus-J


h


---Lateral Superior Genicular Artery


-Lateral Head of Gastrocnemius

• Plantaris

---Lateral Inferior Genicular Artery

— Anterior Tibial Artery Posterior Tibial Artery _Peroneal Artery.


Posterior Tibial Nerve-.

Posterior Tibial Artery

Flexor Digitorum Longus_

Tibialis Posterior_I


Tibialis Posterior


.Peroneus Longus


Flexor Hallucis Longus


Peroneus Brevis


^.Flexor Hallucis Longus


Peroneus Longus .Peroneus Brevis

_Tendo Calcaneus (reflected)


Fig. 376. —The Back of the Right Leg (Deep Dissection).

^ it, an arrangement which results from the posterior tibial nerve hviding into its terminal branches at a higher level than the artery.

40



















626


A MANUAL OF ANATOMY


Branches. —In addition to numerous muscular and cutaneou branches, the latter being distributed to the skin on the back an< inner side of the leg, the posterior tibial artery gives oh the followin; branches:

The nutrient artery is peculiar in being the largest nutrient arter; in the body. Arising a short distance below the lower border of tti popliteus, it passes through the substance of the tibialis posterior an< enters the nutrient foramen of the tibia, accompanied by the nutrien nerve, a branch of the nerve to the popliteus.

The peroneal artery is the largest branch, and is often as large as th continuation of the posterior tibial artery, from which it arises abou i inch below the bifurcation of the popliteal artery. It first incline downwards and outwards, lying superficially to the tibialis posterior At a lower level it descends vertically, lying deeply to the flexor halluci longus and in close approximation to the shaft of the fibula. At som little distance above the ankle-joint it escapes from under cover of th flexor hallucis longus, and ends by dividing into two terminal branches anterior and posterior.

It is convenient to remember that in a horizontal section of the lower liml one inch below the level of the knee-joint one large artery only, the popliteal will be involved; if the section is made two inches below the joint two larg arteries, the anterior and posterior tibials, will be severed; but if the sectioi takes place at three inches or more below the joint, three large arteries, the peroneal in addition to the two tibials, will be cut across.

Branches. —In addition to muscular and cutaneous branches, th< latter supplying the skin on the back and outer side of the leg, th< peroneal artery gives off the following branches:

The nutrient artery to the fibula.

A communicating branch usually arises from the posterior termina branch a short distance above the ankle-joint, passes transversely inwards and anastomoses with the corresponding branch of the posterior tibial artery.

The anterior terminal branch passes forwards through the lowei part of the interosseous membrane. On the front of the leg it descend: deeply to the peroneus tertius, and in front of the inferior tibio-fibulai joint. On the dorsum of the foot it anastomoses with the latera anterior malleolar branch of the anterior tibial and the lateral tarsa branches of the dorsalis pedis.

The lateral calcanean branches continue the direction of the peronea artery and pass downwards behind the lateral malleolus to the outei side and finally to the under side of the heel. They anastomose will the medial calcanean branches of the posterior tibial and latera plantar arteries. The peroneal artery is accompanied by two vena; comites.

Varieties of the Peroneal Artery. —The level at which this vessel arises i subject to variation. It may be at a higher level or at a lower level than norma] In the former case it may be a branch of the popliteal or of the anterior tibia] the peroneal artery is often enlarged, and replaces the posterior tibial to


THE LOWER LIMB


627


arying extent. The peroneal artery supplements the supply of blood to the orsum of the foot, and may be so enlarged as to take the place of the dorsalis sdis artery.

The communicating branch arises a little distance above the ankle)int. It passes transversely outwards deeply to the tendon of the exor hallucis longus, and anastomoses with a corresponding branch

f the peroneal artery. (I* Ik- l^eriXp-yXcrJ

The malleolar branches, often two in number, pass inwards deeply 3 the tendons of the flexor digitorum longus and tibialis posterior, nd ramify on the medial malleolus.

The medial calcanean branches pass through the flexor retinaculum, eeply to which it arises, and is distributed to the inner aspect and nder side of the heel, where it anastomoses with the calcaneal branches f the lateral plantar and peroneal arteries.

The terminal branches are the medial and lateral plantar arteries.

Varieties of the Posterior Tibial Artery.— This vessel may be much diminished 1 size. In such cases the peroneal artery is relatively increased, and by means f an enlarged communicating branch conveys blood to the distal end of the osterior tibial artery. In rare cases the vessel does not extend to the ankle, nd may be entirely absent, in which cases the deficiency is made good by an nlarged peroneal artery.

The posterior tibial nerve (Fig. 376) is the continuation of the medial popliteal, and commences at the lower border of the popliteus muscle. It ends behind the medial malleolus, and under cover of the lexor retinaculum, by dividing into the medial and lateral plantar terves. The division usually takes place at a higher level than that >f the artery. From its commencement the nerve inclines downyards and inwards to the interval between the medial malleolus and he heel. It accompanies closely, and has the same general relations is, the posterior tibial artery, to the inner side of which it lies at its commencement, but crossing the artery superficially it lies on its )uter side in the lower part of the leg.

The branches are muscular, medial calcanean, articular, and terminal.

The muscular branches are given off from the upper part of the lerve, and supply the flexor digitorum longus, tibialis posterior, flexor lallucis longus, and soleus. The branch to the soleus enters the deep )r anterior surface of the muscle. The nerve to the flexor hallucis ongus is a long nerve which accompanies the peroneal artery, to vhich it furnishes branches, and also supplies a nutrient nerve to the ibula.

The medial calcanean branches arise under cover of the flexor 'etinaculum, through which they pass. They supply the skin on the nner side of the heel and the hinder part of the sole of the foot.

The articular branches arise from the posterior tibial nerve close to ts termination. They pass through the medial ligament and supply the ankle-joint.

The terminal branches are the medial plantar and lateral plantar serves.


628


A MANUAL OF ANATOMY


THE KNEE-JOINT.

The articular surfaces taking part in the joint are provided by th femur, patella, and tibia. The articular surfaces of the two femora condyles play upon the two shallow, cup-like, articular surfaces o the upper surface of the tibia; the patellar surface of the femur cor fluent with the condylar surfaces articulates with the patella. Th ligamentous apparatus consists of a capsular investment supple mented by accessory ligaments and a large number of intracapsula structures.

The capsular ligament is a more or less cylindrical arrangemen surrounding the joint, but is so obscured by accessory or supplement ing ligaments that it is only obvious on its posterior aspect, and her only to a limited extent, on the posterior surfaces of the two femora condyles. In these situations it is represented by a comparatively thin membrane, which on the back of the medial condyle usually presents a deficiency through which the large bursa situated deeply to the semimembranosus and inner head of the gastrocnemius is con tinuous with the synovial membrane. The capsular ligament is only partially visible on the back of the lateral condyle, as its upper par is clothed superficially by a part of the oblique posterior ligament, t< which the tendon of the outer head of the gastrocnemius, usually containing a sesamoid cartilage, is adherent. At a lower level th capsular ligament can be distinguished, and here a bursa intervene: between it and the tendon of the outer head of the gastrocnemius; i also gives passage to the tendon of the popliteus (Fig. 378).

Attachments of Capsular Ligament —Femoral Attachments .—Ii front the capsule lies deeply to the tendon of the quadriceps femori: and is very thin. It is attached to the front of the femur some distant above the level of the patellar surface, and covers a pouch of synovia membrane prolonged upwards on to the front of the shaft of the femur The attachment to the bone is usually interrupted, as the pouch 0 synovial membrane is, in most cases, continuous with the subcrura bursa through a deficiency in the capsule. On the lateral aspects 0: the condyles the attachment follows the lower limits of the two epi condyles some distance above the margins of the articular cartilage being just below the epiphysial line on the lateral condyle, but some considerable distance below it on the medial condyle.

On the back of the femur the line of attachment is close to the uppei margins of the condylar articular surfaces, but above the epiphysia line; it is here inseparable from the attachments of the gastrocnemius Between the two condyles it crosses the intercondylar notch behinc the femoral attachments of the cruciate ligaments.

Ihe capsular ligament is adherent deeply to the two semilunar cartilages and its lower part, which extends from the semilunar cartilages to the tibia and serves to keep them in place when the femoral attachments of the ligamenl are severed, is known as the coronary ligament, but has no real claim to be dis tinguished by a special name.


THE LOWER LIMB


629


Tibial Attachments .—On the sides of the tibia the line of attachment s some little distance below the margins of the articular cartilage. n front it dips downwards on either side to the level of the tubercle )f the tibia. Behind it dips downwards opposite the popliteal notch

o the lower limit of the attachment of the posterior cruciate ligament. \t the back of the lateral condyle the line of attachment is interrupted

or the passage of the tendon of the popliteus. Accessory Ligaments. —The front of the joint is occupied by the piadric.eps femoris represented by the common tendon, the patella, ind the ligamentum patellae.

The ligamentum patellae is a thick, broad band, attached above to he apex and adjacent margins of the patella, below to the lower rough Dart of the tubercle of the tibia. A bursa intervenes between it and

he upper smooth part of the tubercle. Above its superficial fibres ire continuous with those of the tendon of the quadriceps by means )f an expansion covering the front of the patella. On either side the Datella retinacula are attached to it.

The medial and lateral patellar retinacula occupy the intervals Detween the patella and the ligamentum patellae in front and the nedial and lateral ligaments on either side. In each patellar retinacuum are two planes of fibres which are closely blended with each other, rhe superficial layer is derived from the deep fascia, which is continuous ibove with the fascia lata of the thigh, and is here firmly adherent to

he deeper layer. To the outer side of the patella the lateral patellar 'etinaculum is especially thick and strong, as its fascial element is Drovided to some considerable extent by the ilio-tibial tract. Deeply

o, and with difficulty separable from, the fascial layer are tendinous expansions of the vastus lateralis et medialis continuous with these nuscles above, and prolonged downwards to the tibia.

Between each patellar retinaculum superficially and the capsular igament deeply are intervals containing connective tissue and tDltfod/essels. The interval is especially well marked on the inner side of

he patella, where the capsular ligament is relatively thick and consists argely of curved fibres which arch backwards from the patella to the linder part of the medial condyle (Fig. 377).

On either side of the joint is a well-marked ligament.

The medial ligament (Fig. 380) is a long, broad, flattened band ittached above to a rough impression on the inner aspect of the medial Dondyle of the femur immediately below the adductor tubercle. It Dasses obliquely downwards and forwards, and is attached below

o the medial condyle of the tibia, where it bridges over the horizontal groove lodging the tendon of insertion of the semimembranosus, which Tus lies deeply to it. From the medial condyle it is prolonged downwards for some considerable distance on the inner aspect of the shaft }f the tibia, and bridges over the depression below the medial condyle, thus forming the roof of a short canal in which the medial inferior genicular branch of the popliteal artery is contained. Its hinder part s adherent deeply to the medial semilunar cartilage. Superficial to the


630


A MANUAL OF ANATOMY


medial ligament, but with a bursa or bursae intervening, are the tendon: of the sartorius, gracilis, and semitendinosus.

Some of the fibres of the tendon of insertion of the adductor magnus ar< prolonged into the medial ligament of the knee-joint, which represents, partiall] at all events, a distal prolongation of the muscle.

The lateral ligament (Fig. 380) is a short rounded cord remarkabl} like a tendon in appearance. Attached above to the prominence or

Vast. Med.


Fig. 377 - —The Medial Side of the Knee (from a Dissection).

The medial patellar retinaculum has been removed to expose the bloodvessels, which are contained in the connective tissue between it and the capsular ligament.

the outer aspect of the lateral condyle of the femur, immediately above the groove lodging the tendon of the popliteus, it extends downwards and backwards, and is attached below to the head of the fibula in front of the styloid process. Lying superficially to it is the tendon of the biceps, a bursa being interposed between them. Just above its fibular attachment the tendon embraces the lower part of the ligament. On its deep aspect, with a synovial pouch between them, is the tendon of the popliteus, which intervenes between it and the lateral semilunar












THE LOWER LIMB


631

cartilage. At a lower level the lateral inferior genicular artery lies deeply to it.

The lateral ligament represents the proximal end of the peroneus Iongus muscle, which in some animals and in the human embryo arises from the lower end of the femur.

The arcuate ligament is a name given to a somewhat indefinite and inconstant band lying behind the lateral ligament and attached below to the styloid process of the fibula. It arches across and is frequently attached to the tendon of the popliteus, which passes through the capsular ligament immediately behind it. It is simply a differentiated band of the capsular ligament.


The oblique posterior ligament (Winslowii) (Fig. 378) is an expansion from the lower part of the tendon of the semimembranosus, which extends obliquely upwards and outwards across the intercondylar notch, and is attached to the lateral condyle of the femur. Deeply it is adherent to the posterior part of the capsular ligament, which it supplements on this aspect of the joint. Passing through it are the middle genicular branch of the popliteal artery and the genicular branch of the obturator nerve.

The intrascaphlar structures include the two semilunar cartilages, the transverse ligament, and the cruciate ligaments.










63 2


A MANUAL OF ANATOMY


The semilunar cartilages (Fig. 379) are two crescentic plates o: fibro-cartilage, which occupy the periphery of the articular surface' in the upper surface of the tibia. They serve to deepen the sockets of reception for the two femoral condyles, and, being movable on the tibia, they, together with the femoral condyles, undergo gliding movements upon the former bone. The extremities of each crescentk plate are fibrous, are the most fixed parts, and are known as the twe horns. Each semilunar cartilage is triangular in section; the narrov base represents a circumferential area adherent to the deep aspect o: the capsular ligament, a concave upper surface is adapted to th( convexity of the femoral condyle, a flattened lower surface rests or the articular surface of the tibia, and an apex or thin lip projects intc the joint cavity.


Tubercle

i

Anterior Cruciate Ligament ; Transverse Ligament


Fig. 379. —The Ligaments and Fibro-cartilages on the Head of the

Right Tibia.


The medial semilunar cartilage is less complete than the lateral being not much more than a semicircle. It is wider behind than ir front. Its anterior horn is attached to the fore end of the depressed area in front of the intercondylar eminence, and is, as a rule, continuous with the transverse ligament. Its posterior horn is attached to the tibia behind the intercondylar eminence immediately in front of the attachment of the posterior cruciate ligament. The medial semilunar cartilage is firmly adherent to the deep aspect of the posterior part of the medial ligament.

The lateral semilunar cartilage is in form nearly a complete circle. Its two horns are close together, and are attached immediately in front of and behind the intercondylar eminence, being embraced by those of the medial semilunar cartilage. It is much more uniform in width than the medial semilunar cartilage. From its posterior aspect







THE LOWER LIMB


633


1 well-marked band, the ligament ofWrisberg (Fig. 380), passes obliquely upwards and inwards, blends with the upper part of the posterior

ruciate ligament, and is attached with it to the fore part of the deep aspect of the medial condyle.


The ligament of Wrisberg usually divides into two bands, which embrace the posterior cruciate ligament; one band blends with its posterior aspect, the other with its anterior. The latter band is known as Humphry's ligament.

The ligament of Wrisberg represents the primitive attachment of the lateral semilunar cartilage in pronograde mammals, in which the cartilage is attachedat one end to the femur, at the other to the tibia.


Anterior Cruciate Ligament — JIM - i


Lateral Semilunar Fibro-cartilage

Synovial Membrane


Lateral Ligament


Capsular Ligament of Superior. Tibio-fibular Joint


Medial Semilunar ' Fibro-cartilage

— Synovial Membrane Medial Ligament


Fig. 380.— The Cruciate Ligaments of the Left Knee-Joint (Posterior View) (after Spalteholz).


The outer aspect of the lateral semilunar cartilage is grooved by the tendon of the popliteus, which intervenes between it and the lateral ligament of knee. The groove is lined with synovial membrane, which is interjected between the tendon and the cartilage.

The transverse ligament (Fig. 379) is a narrow band towards the front of the joint, and links the two semilunar cartilages together. Medialfy it is continuous with the anterior horn of the medial semilunar cartilage, from which it passes outwards to blend with the anterior aspects of the lateral semilunar cartilage. It is sometimes absent.











634


A MANUAL OF ANATOMY


The two cruciate ligaments (Fig. 381) are two strong ligamentous bands which fasten the femur and tibia directly together. They cross each other as they pass upwards from the area between the twc articular surfaces of the tibia to the intercondylar notch, where the} are attached to the deep aspects of the two condyles.

The anterior cruciate ligament is attached below to the rough area in front of the intercondylar eminence between the attachments oi the anterior horns of the two semilunar cartilages, that of the media] being in front of it and the lateral behind it. It passes very obliquely upwards, backwards, and outwards, and is attached to the hinder end of the deep aspect of the lateral condyle.


Posterior Cruciate Ligament Patellar Facet

Medial Condyle.


Medial Semilunar Fibro-cartilage


--JwA-Lateral Condyle


-Anterior Cruciate Ligament

_Lateral Semilunar

Fibro-cartilage — Lateral Ligament

"CTransverse Ligament

_Capsular Ligament ot

Superior Tibio-fibular Joint


Fig. 381.— The Cruciate Ligaments of the Left Knee-Joint

(Anterior View).


1 he posterior cruciate ligament, thicker and shorter than the anterior, is attached below to the floor of the popliteal notch at the back of the upper end of the tibia, and behind the attachments of the posterior horns of both semilunar cartilages. It passes obliquely upwards, forwards, and inwards; it is attached above to the fore part of the deep aspect of the medial condyle. The posterior aspect of its upper end is joined by the ligament of Wrisberg, and Humphry’s ligament, when present, blends with its anterior aspect. By means of these ligaments it is fastened to the posterior surface of the lateral semilunar cartilage .

The synovial membrane (Fig. 383) is very extensive. It lines the deep aspect of the capsular ligament above and below the semilunar cartilages. It is not infolded into the joint to provide an investment













THE LOWER LIMB


635


or the semilunar cartilages, as is usually described, but comes to an

nd, above and below, close to the circumferential limits of these tructures. From the deep aspect of the posterior part of the capsular igament it is inflected into the joint as a double-layered fold investing he two cruciate ligaments. The two layers are continuous with each )ther in front of the two cruciate ligaments, and also through a small nterval between them, thus forming a kind of bursal arrangement liminishing friction between the two ligaments. The posterior aspect )f the posterior cruciate ligament is bare of synovial membrane, as it


Fig. 382. —Interior of the Left Knee-Joint (Anterior View).


is in direct contact with the capsular ligament. Towards the fiont of the joint the synovial membrane invests a large conical mass of fat, the lower part of which occupies the interval between the ligamentum patellae and the lower part of the patella in front, and the tibia behind. From the apex of the pad of fat a band-like fold, the infrapatellar synovial fold {ligamentum mucosuni ), extends backwards and upwards, and is attached to the front end of the intercondylar notch of the femur. The synovial membrane investing the lateral limits of the pad of fat is disposed as two fringed folds, the alar folds (Fig. 3 & 2 )> which diverge





















636


A MANUAL OF ANATOMY


from the lower limit of the synovial fold and arch forwards and outwards to the lateral margins of the articular surface of the patella. The alar folds form the upper limits of a pouch of synovial membrane between the lower part of the patella in front and the pad of fat behind.

The synovial membrane extends upwards for some distance above the level of the patella, and is, in most cases, continuous here with the large bursa between the tendon of the quadriceps and the shaft of the femur. At the junction of this suprapatellar pouch of synovial membrane with the bursa are fringed folds containing fat.


Popliteus .. Lateral Ligament—


_Suprapatellar Bursa

_Quadriceps Femoris


Pouch of Synovial Membrane of Knee-join


Patella


..Semilunar Fibro-cartilage ..Ligamentum Patellse


Bursa beneath Ligamentum Patellae


Iog. 383.—The Synovial Membrane of the Right Knee-Joint (Lateral Aspect) (after Spalteholz).


A transverse section through the knee-joint of a human embryo exhibits three cavities—two posterior or condylo-tibial joint cavities, lying side by side, and completely independent of each other, being separated by a vertical partition; an anterior or subpatellar cavity, which is to be regarded as an enlarged bursal sac between the tendon of the quadriceps and the capsule clothing the two condylo-tibial joint cavities in front. The three cavities become one, and give rise to the single complicated cavity of the knee-joint by the partial disappearance of the partition between the two posterior cavities and the anterior cavity, whereby the latter communicates with both condylo-tibial cavities behind. The partition between the two condylo-tibial cavities persists, and is modified into the two cruciate ligaments. The remnants of the partition between the subpatellar cavity and the two condylo-tibial cavities are represented by the infrapatellar synovial fold and the synovial folds, the pouch of synovial mem





THE LOWER LIMB


6.37


rane behind the lower part of the patella being the persistent lower part of the nbpatellar bursal sac. The capsular ligament is regarded by some anatomists s being inflected into the joint from behind, the inflected part being represented y the connective tissue basis of the synovial membrane investing the cruciate gaments. According to this view, the two cruciate ligaments are extracapsular tructures.

The arterial supply is derived from the extensive anastomosis about he joint, in which branches of the popliteal, descending branch of lateral ircumflex, descending genicular, and tibial arteries take part.

The nerve-supply is very extensive, and is derived from the sciatic >y means of twigs from its terminal popliteal branches, from the emoral, and from the obturator nerves.


Posterior Ligament — Posterior Cruciate Ligament


Anterior Cruciate Ligament


-Vastus Intermedius

-Articularis Genu

-Suprapatellar Bursa


Pouch of Synovial Membrane of Knee-Joint


Prepatellar Bursa


— Ligamentum Patell® Infrapatellar Synovial Fold

—Infrapatellar Pad of Fat

-Bursa beneath Ligamentum

Patellae

-Skin


Fig. 384.—Sagittal Section of the Right Knee-Joint viewed

from the Outer Side.


Genicular branches from the medial popliteal nerve accompany the two medial genicular and the middle genicular branches of the popliteal artery. Genicular branches from the lateral popliteal nerve accompany the two lateral genicular arteries and the anterior tibial recurrent artery (p. 550). The terminal twigs of the three musculai branches of the femoral supplying the vastus lateralis, vastus intermedius, and vastus medialis respectively end in the joint, that derived from the nerve to the vastus medialis being the largest and most important (p. 574). The supply from the obturator is the genicular branch, the terminal branch of its posterior division (p. 580) The movements taking place in the knee-joint are chiefly flexion and extension, with which gliding and rotation movements are associated.

The complicated movements occurring in extension and flexion of the knee




A MANUAL OF ANATOMY


638

joint are most easily understood by studying the sequence of events when tb joint passes from the position of extreme flexion to that of extreme extensior the feet being firmly planted on the ground. In the fully flexed position th extreme hinder parts of the two condylar surfaces of the femur, each graspe by the corresponding semilunar cartilage, rest on the hinder parts of th articular surfaces of the tibia. As flexion commences the two condyles begi to roll parallel to each other in the cups provided by the semilunar cartilage; which, being elastic structures, adapt themselves to the varying curvature of the two condyles. As the movement progresses the parallel rolling of th two condyles continues, and at the same time the semilunar cartilages sli forwards on the tibia, with the result that the contact surface of each condyl with the tibia and the transverse axis about which the rolling takes place als move forwards. This continues until the rolling of the lateral condyle is brougb to a stop, and a groove which marks the junction of its articular surface wit the patellar surface comes into contact with the anterior edge of the semiluna


Fig. 385. —The Articular Surface at the Lower End of the Femur

viewed from Below.

The black arrows indicate the direction of movement in the two condyles during the greater part of extension; the red arrows show the direction of move ment during the final stage, when the femur rotates inwards. E is th( groove on the lateral condyle which is in contact with the lateral semilunai cartilage at end of first stage of extension; I is the groove on the media! condyle in contact with the medial semilunar cartilage at the end of the final rotation; C a point on the vertical axis about which the final rotation takes place.

cartilage. At this stage the rolling of the medial condyle is incomplete, as its articular surface is prolonged farther forwards than that of the lateral condyle, In the final stage of extension the femur rotates inwards. The lateral condyle pivots round about a vertical axis, while the medial condyle goes on rolling, but now wheels round the vertical axis, passing through the lateral condyle. The pivoting of the lateral condyle and the wheeling movement of the medial condyle are finally brought to a stop by the tension of all the strong ligaments about the joint. At the end of the final stage the groove marking the junction of the tibial articular surface of the medial condyle with the patellar surface comes into contact, in its turn, with the front edge of the medial semilunar cartilage. When the foot is off the ground the tibia rotates outwards on the femur in the final stage of extension, but the same relative displacement takes place between the two bones.

It is to be noted that the front part of the articular surface of the medial condyle is bent outwards, and is bounded on either side by two curved edges,




THE LOWER LIMB


639


ach of which is a segment of a circle, of which the common centre is a point >n the lateral condyle. This point indicates the position of the axis round diich the lateral condyle pivots.

The inward rotation of the femur on the tibia, which marks the final stage if extension, is said to lock the knee-joint. When standing in the erect posture rith the knees fully extended the line of the centre of gravity falls in front of he axis of rotation of the joint, and will tend further to extend it, but this is >revented by all the strong ligaments about the joint, the medial and lateral igaments, the cruciate ligaments, and the oblique posterior ligament all being on he stretch at the end of the movement. Further, in this position the grooves vhich mark the front limits of the condylar articular surfaces are firmly pressed igainst the anterior edges of the two semilunar cartilages. Such is the automatic irrangement whereby the erect posture can be maintained as far as the kneeoint is concerned, with a minimal expenditure of muscular energy.

Flexion Movements .—When bending the knees in the standing position an )utward rotation of the femur must take place as a preliminary movement,

he lateral condyle pivoting round on a vertical axis and the medial condyle mdergoing a wheeling movement. Before the femur can rotate outwards lexion must also take place at the hip-joint, in order to relax the ilio-femoral igament, the outer band of which would prevent outward rotation of the femur n the extended position of this joint. This preliminary movement of rotation s said to unlock the knee-joint. When it is completed, the two articular conlylar surfaces in contact with the tibia are parallel with each other, and both

ommence to roll in their articular cups, at the same time sliding backwards with the two semilunar cartilages on the tibia. In other words, the movement ls the exact converse of that occurring during the greater part of extension, and continues until full flexion is attained. Extreme flexion is usually limited by the meeting and compression of the soft masses on the back of the thigh and of the calf respectively, although the posterior cruciate ligament is said to be on the stretch.

Rotation .—In considering rotation it must be kept in mind that when the foot is on the ground the leg is fixed, and no rotation of the tibia can occur, but the femur can rotate on the tibia. When the foot is off the ground the leg can be rotated outwards and inwards on the thigh to a limited extent. Rotation movements of the tibia on the femur cannot take place when the joint is extended, and are most free when it is in the semiflexed position. The rotation of the tibia in the semiflexed position is one which takes place about a vertical axis between the articular surfaces, the inner tibial surface moving backwards and the outer surface moving forwards during medial rotation, the reverse movements taking place during lateral rotation. In either case the movement of the inner tibial surface is more extensive than that of the outer. The movements are of an altogether different kind to the rotations occurring at the end of extension and at the beginning of flexion. Inward rotation of the tibia is limited by the anterior cruciate ligament being put on the stretch, the movement tending to wind up the ligaments. In outward rotation the cruciate ligaments are unwound and relaxed; it is limited by the tension of the medial and lateral ligaments.

Movements of the Patella .—With the movements of flexion and extension the patellar or trochlear surface of the femur must glide upwards and downwards respectively on the posterior surface of the patella, the patella itself remaining practically stationary. When the joint is in the extended position the greater part of the patella is at a higher level than the trochlear surface, and its lowermost pair of facets only are in contact with it. As flexion proceeds the trochlear rises; the two intermediate patellar facets and later the uppermost pair, each in turn, come in contact with it. In extreme flexion the increasing projection forwards of the medial condyle tilts the patella outwards, and the inner vertical facet on its articular surface comes into contact with the semilunar facet on the outer aspect of the medial condyle.

When the knee-joint is flexed, a space towards the front of the joint opens up


640


A MANUAL OF ANATOMY


between the articular surfaces. In this movement the infrapatellar synovia fold is drawn upwards, with the result that the conical pad of fat to which it is attached is pulled upwards and occupies the space. This is an automatic arrangement comparable with that of the ligament of head of femur (p. 593).


The bursae about the knee-joint are very numerous, as the surrounding tendons come into closer relation with the bones taking part in the formation of the joints than is the case in most joints.

On the Front of the Joint .—


Fig. 386. —Plan of Insertion of Tendon (SM) of Semimembranosus on Medial Side of Tibia, Deep to Medial Ligament of Knee, with a Bursa (Dotted Line).

Above this bursa the tendon is in contact with medial head (G) of gastrocnemius, another bursa intervening, prolonged between the tendon lower down and condylar capsule.


Above the level of the patella is the suprapatellar bursa, which lies deeply to the tendon of the quadriceps femoris, and in most cases communicates with the pouch of the synovial membrane, extending upwards in front of the lower part of the shaft of the femur. In front of the patella there are usually two bursae, known as the prepatellar-, bursae, one subcutaneous and the other subfascial. Below the level of the patella a subcutaneous bursa lies in front of the tubercle of the tibia and the lower part of the ligamentum patellae, and a deeper one between the ligamentum patellae and the upper smooth part of the tubercle by fat of the tibia. The latter bursa extends upwards, and is separated from the anterior aspect of the tibia, above the level of the tubercle.

On the back of the joint the largest and most important bursa, which usually communicates with the synovial cavity, lies deeply to the inner head of the gastrocnemius and the


semimembranosus. A smaller bursa lies deeply to the outer head of the gastrocnemius.

On the inner aspect of the joint a large bursa, sometimes represented by two bursae, intervenes between the medial ligament and the tendons of the sartorius, gracilis, and semitendinosus. Deep to the medial ligament is a bursa between the tendon of the semimembranosus and] the upper lip of the horizontal groove on the medial epicondyle of the tibia in which the tendon lies.









THE LOWER LIMB


641


On the outer side of the joint a bursa lies deeply to the tendon of the deeps, between it and the lateral ligament. A pouch of the synovial nembrane ensheathes the tendon of the popliteus, separates it from

he lateral ligament superficially, and from the lateral semilunar carriage deeply. A prolongation of this synovial sheath extends upwards, md lies between the tendon of the popliteus and the lateral femoral

ondyle, while another prolongation follows the tendon as it passes hrough the capsular ligament, and, extending downwards, intervenes Detween it and the back of the upper end of the tibia.

SOLE OF THE FOOT.

Landmarks. — On the inner side of the foot, about an inch below fie medial malleolus, the ridge-like projection of the sustentaculum

ali may possibly be felt. In front of the sustentaculum tali is a very Drominent projection caused by the tuberosity of the navicular bone, md between them a depression, occupied deeply by the tendon of the

ibialis posterior and the plantar calcaneo-navicular ligament. This iepression marks the position of the talo-navicular joint. The projection caused by the tuberosity of the navicular bone is one of the nost important surgical landmarks in the foot. In front of the tuberosity of the navicular bone the medial cuneiform, the first metatarsal, and the marked prominence of the metatarso-phalangeal joint Df the great toe can all be distinguished, in this order from behind forwards.

On the outer border of the foot at about its mid-point is an easily recognizable projection caused by the prominent tubercle on the outer fide of the base of the fifth metatarsal bone. A point midway between this prominence and the tip of the lateral malleolus marks the position uf the calcaneo-cuboid joint, which it may be noted is in the same transverse plane as the talo-navicular joint on the inner side of the foot.

The Plantar Arteries. —The lateral plantar artery crosses the foot twice, first passing obliquely forwards and outwards towards the miter side of the foot, and then, changing its direction, crosses to the inner side of the foot. The first part of the artery is indicated by a iine drawn from a point midway between the medial malleolus and the projection of the heel to a point about a finger’s breadth to the finer side of the tuberosity of the fifth metatarsal; the second part by 1 line drawn from the latter point to the proximal end of the first intermetatarsal space. The position of the medial plantar artery is indicated by a line drawn from a point midway between the medial malleolus md the projection of the heel to about the middle of the plantar aspect 3 f the ball of the great toe.

Subcutaneous bursae are usually found in situations where the foot fs subject to the greatest pressure. These situations are more particularly the under side of the heel, the plantar and inner aspects of the metatarso-phalangeal joint of the great toe, and the plantar aspect

41


642


A MANUAL OF ANATOMY


of the head of the fifth metatarsal bone. Occasionally bursae are foun on the outer side of the tuberosity of the fifth metatarsal and on tb tuberosity of the navicular bone.


Abductor Hallucis-:


Flexor Hallucis Longus_;


Flexor Hallucis Brevis,


—-Flexor Digitorum Brevis -- 'Abductor Digiti Minimi


--•Flexor Digiti Minimi

I^Lumbricales


Fig. 387. —The Plantar Aponeurosis and First Layer of Muscles

(in Part).


The deep fascia of the sole, known as the plantar aponeurosii (Tig. 387), consists of three portions, a central, medial, and lateral. Th< junctions of the former with the latter are indicated by two longi










































THE LOWER LIMB


643


udinal grooves. The central portion chiefly consists of longitudinal bres, and is exceedingly thick and strong, while the two side portions, 1 which transverse fibres predominate, are relatively thin. Between he plantar aponeurosis and the skin are numerous fibrous bands which >ind the two together. The spaces between the fibrous bands are ccupied by masses of finely lobulated fat, representing the superficial ascia, which, in the sole, is thick, dense, and resistant.

The central portion covers the flexor digitorum brevis superficially, nd is triangular in outline. Behind it is very narrow, and is attached 0 the large inner tubercle at the hinder end of the plantar aspect of he calcaneum. As it passes forwards towards the toes it widens and tecomes thinner. Opposite the heads of the metatarsal bones it divides ato five digital processes. The direction of its fibres is chiefly longiudinal, but towards the toes transverse fibres are superadded.

In the webs of the toes the transverse fibres form a more or less Listinct band, the superficial transverse ligament, which bridges over he intervals between the digital processes and covers the digital rteries and nerves, together with the lumbrical muscles, superficially. Lach digital process ends by becoming continuous with the fibrous lexor sheath; while some of its superficial fibres are attached to the kin. From each side of a digital process a lateral slip passes in deeply 0 join the deep transverse ligament, and thus completes the comnencement of a tunnel in which the flexor tendons, as they pass on 0 a toe, are contained.

The central part of the plantar aponeurosis, by playing the part of a string o a bow, is an important factor in maintaining the longitudinal arch of the foot, "he central part of the plantar aponeurosis and its digital processes, with their ateral slips, represent the tendons of a flexor of the proximal phalanges of the oes, a muscle which is well developed in many animals. The proximal part of he muscle is represented by the plantans (p. 620).

The lateral portion invests the abductor digiti minimi muscle. At ts line of junction with the central portion is the lateral intermuscular eptum, which is prolonged deeply into the sole; laterally it is coninuous round the outer border of the foot with the deep fascia of the lorsum. A strong band of this portion extends between the outer ubercle of the calcaneum and the tuberosity on the outer side of the )ase of the fifth metatarsal bone. This band is sometimes replaced by nuscle fibres, the abductor ossis metatarsi quinti.

The medial portion invests the abductor hallucis muscle, and is continuous posteriorly with the flexor retinaculum. At its line of unction with the central portion is the medial intermuscular septum; nedially it is continuous round the inner border of the foot with the leep fascia of the dorsum.

The two intermuscular septa, medial and lateral, are situated on ‘ither side of the flexor digitorum brevis, between it and the abductor lallucis on the one side and the abductor digiti minimi on the other, ^ach septum gives attachment to the two muscles between which it les - The two septa are continuous deeply with the ligamentous and


A MANUAL OF ANATOMY


644

tendinous structures clothing the plantar aspect of the tarsus and th interosseous fascia investing the metatarsal bones and the interosseor muscles.

The cutaneous nerves (Fig. 392) which supply the skin of the so] are the medial calcanean from the posterior tibial, and branches ( the medial and lateral plantar nerves.

The medial calcanean nerve is a branch of the posterior tibial give off under cover of the flexor retinaculum. It passes through the ligc ment, and a branch supplies the skin on the under side of the heel.

The plantar cutaneous branches of the medial plantar nerve appe^ in the groove between the abductor hallucis and flexor digitorum brevi: They are distributed to the skin of the inner half of the sole.

The plantar cutaneous branches of the lateral plantar nerve appes in the groove between the flexor digitorum brevis and abductor digi minimi. They are distributed to the skin of the outer half of the sol

The skin on the outer side of the heel and the outer border of the foe is supplied by the sural nerve, that of the inner border of the foot b the saphenous, and distal to the metatarso-phalangeal joint of th great toe by the medial branch of the musculo-cutaneous nerve.

Cutaneous Arteries. —The skin of the heel is supplied by the medic calcanean branches of the posterior tibial and of the lateral plants arteries, and by the lateral calcanean branch of the peroneal artery. Th skin covering the rest of the sole is supplied by branches of the later; and medial plantar arteries, which accompany the cutaneous branche of the corresponding nerves.

Superficial Veins. —A close network of very small veins occupies th subcutaneous tissue of the sole. It is drained by vessels windin round the borders of the foot to join the dorsal plexus, and also by th plantar venous arcade, a vein crossing the distal part of the sole clos to the roots of the toes. The venous arcade receives small veir draining the toes, and joins the dorsal plexus by veins which win round the borders of the foot, and also by interdigital veins which pas directly upwards, between the toes, opposite the interdigital clefts.

Muscles.-— The muscles of the sole are disposed in four layers.

The first layer (Fig. 388) consists of three muscles which lie deepl to the three portions of the plantar aponeurosis; the flexor digitorui brevis occupies a central position, and the abductors of the two margin; toes, the abductor hallucis and the abductor digiti minimi respectively lie on either side of it.

Abductor Hallucis (Fig. 388)— Origin .—From the inner side of tt large inner tubercle on the plantar aspect of the calcaneum, and froi the lower border of the flexor retinaculum. Many of its fibres ark from the plantar aponeurosis covering it, and from the medial inte] muscular septum.

Insertion .—By a tendon which blends with that of the inner hea the flexor hallucis brevis, with which it is inserted into the inner sid of the base of the proximal phalanx of the great toe.

Nerve-supply .—The medial plantar nerve.


THE LOWER LIMB 645

Action .—Abducts the great toe, and flexes its metatarso-phalangeal oint.

Flexor Digitorum Brevis (Fig. 388)— Origin .—By a narrow tendon .ttached to the apex of the large inner tubercle on the plantar aspect


Abductor Digiti Minimi---a


Outer Digital Branch of

Lateral Plantar Nerve Lateral Plantar Artery—


I nner Digital Branch of Lateral Plantar Nerve ‘


Communicating Nerve. Flexor Digiti Minimi Brevis,


Central Division of Plantar Aponeurosis (cut)


—'Abductor Hallucis


—Flexor Digitorum Brevis


Medial Plantar Nerve and Artery


_.Flexor Hallucis Brevis


Tendon of Flexor Hallucis Longus


Fig. 388. —The First Layer of Plantar Muscles (Left Foot).


3 f the calcaneum; most of its fibres arise from the deep surface of the -entral portion of the plantar aponeurosis, and from the two intermuscular septa.

Insertion .—By four tendons attached to the four outer toes.
























646


A MANUAL OF ANATOMY


Nerve-supply. —The medial plantar nerve.

Action. —Flexes the intermediate phalanges of the four outer toes.

On the plantar surface of a toe each tendon is accompanied by ; tendon of the flexor digitorum longus, which lies deeply to it, the tw< tendons being contained in a fibro-osseous canal lined by a synovia sheath. Opposite the base of the proximal phalanx the brevis tendoi divides into two slips, which wind round on either side of, and unit' on, the deep aspect of the longus tendon, which thus passes throug] it; hence the name flexor perforatus for the brevis muscle. At th distal end of the proximal phalanx the tendon splits again into tw< diverging slips, which are attached to the sides of the shaft of th intermediate phalanx. Each brevis tendon has a vinculum brevis which is reflected from its deep aspect to the distal end of the proxima phalanx.

The fibrous sheaths (vaginal ligaments) which, with the phalanges form the fibro-osseous canals in which the flexor tendons are containe( have the same general arrangement as in the fingers (p. 492). Th entrance to the proximal end of one of these canals is a short tunne formed by a digital process of the plantar fascia superficially, by it two lateral slips on either side, and deeply by the deep transverse ligament.

Abductor Digiti Minimi (Fig. 388)— Origin .—From the small latera tubercle on the plantar aspect of the os calcis, from the surface 0 bone in front of it, and from the outer side of the large medial tubercle Many of its fibres are also attached to the plantar aponeurosis covering it, and to the lateral intermuscular septum.

The distal part of the muscle is mainly tendinous, and glides ove the base of the fifth metatarsal bone, to which it is occasionally adherent.

Insertion .—The outer side of the base of the proximal phalanx of th little toe, in common with the flexor digiti minimi brevis.

Nerve-supply. —The lateral plantar nerve.

Action. —Abducts the little toe, and flexes its metatarso-phalangea joint.

The abductor digiti minimi, especially towards its distal end, is often replace by tendon to a greater or less extent. It has occasionally an additional sli of origin from the prominent tubercle at the base of the fifth metatarsal bone.

The second layer (Fig. 389) consists of the tendons of the two lonj digital flexors, the flexor digitorum longus and flexor hallucis longu respectively; and two sets of muscles, the flexor accessorius and th lumbricals, both associated with the tendon or tendons of the flexo digitorum longus.

The tendon of the flexor hallucis longus is prolonged from th' groove on the inferior aspect of the sustentaculum tali directly for wards to the great toe, and lies towards the inner side of the foot. Th tendon of the flexor digitorum longus, which in the hinder part of th sole is lying to the inner side of the tendon of the flexor hallucis longue is directed obliquely forwards and outwards and crosses superficial!;


THE LOWER LIMB


647


he tendon of the flexor hallucis longus, to which it is attached by a tendinous slip (p. 624). After crossing the flexor hallucis longus the tendon of the flexor digitorum longus subdivides into digital tendons, to which the lumbrical muscles are attached. Implanted into it from behind is the accessorius muscle.

The flexor accessorius arises by two heads.

Origin .—The inner head, which is broad and fleshy, arises from the internal concave surface of the calcaneum below the sustentaculum


Fig. 389.—The Second Layer of Plantar Muscles (Left Foot).

tali. The outer head, narrow and tendinous, arises from the plantar aspect of the calcaneum immediately in front of the small latera tubercle, but chiefly from the long plantar ligament, which here clothes the bone. " .

Insertion .—The posterior and deep aspects of the tendon ol e flexor digitorum longus.

It may be attached to the plantar aspect of the tendon of the flexor digitorum longus, and in some cases embraces it.










648


A MANUAL OF ANATOMY


Nerve-supply. —The lateral plantar nerve.

Action. —The muscle probably never contracts independently, bu always in conjunction with the flexor digitorum longus. Passinj directly forwards from its origin to its insertion, it neutralizes th< oblique pull of the flexor digitorum longus, which in flexing the toe would otherwise drag them inwards.

The accessorius is probably a part of the flexor digitorum longus which ha migrated into the foot. In support of this view it is interesting to note that th inner head of the muscle may occasionally be prolonged upwards into the leg The flexor digitorum longus is one of the muscles engaged in extending the foot and in full extension may be incapable of further contraction. It is possibl that in this position of the foot the accessorius is the chief agent concerned ii flexing the toes.

The Lumbrica! Muscles (Fig. 389) are four small muscles whicl occupy the distal part of the sole where they are found in associatioi with the tendons of the flexor digitorum longus. They are remarkabh in 'that they have no direct attachment to the skeleton.

Origin. —They are all attached to the adjacent sides of the tw< tendons of the flexor digitorum longus, between which they lie, witl the exception of the first or innermost, which arises from the inne] side of the long flexor tendon of the second toe.

Insertion. —The tendons wind round on the inner side of the meta tarso-phalangeal joints of the four outer toes, and blend with the extensor expansion on the dorsal aspect of the proximal phalanx.

Nerve-supply . —The innermost or first lumbrical is supplied by the medial plantar nerve. The outer three lumbricals are supplied b) the deep division of the lateral plantar nerve.

Action. —Flex the metatarso-phalangeal joints, and extend the interphalangeal joints.

The muscles are detached parts of the flexor digitorum longus.

The third layer (Fig. 390) consists of the short muscles of the twc marginal digits, with the exception of the two abductors, which wen found in the first layer. There are two muscles of the great toe: a short flexor and an adductor; one muscle of the little toe, a shorl flexor.

Flexor Hallucis Brevis (Fig. 390)— Origin. —From the plantai surface of the cuboid, and from the prolongations of the tendon of the tibialis posterior to the intermediate and lateral cuneiform bones.

Insertion. —The muscle divides into two heads, each of which ends ir a tendon. The tendon of the inner head is inserted on the inner side of the base of the proximal phalanx of the great toe in common with the abductor hallucis; that of the outer head into the outer side of the base of the same phalanx in common with both heads of adductor hallucis. The two tendons blend with the capsular ligament of the metatarso-phalangeal joint, and in this situation each tendon contains a large sesamoid bone.

Nerve-supply. —The medial plantar nerve.

Action. —Flexes the metatarso-phalangeal joint of the great toe.


THE LOWER LIMB


649


Adductor Hallucis (Oblique Head) (Fig. 390)— Origin .—The plantar urfaces of the bases of the second, third, and fourth metatarsal bones, •ut chiefly from the sheath of the peroneus longus tendon immediately iehind them.

Insertion .—The outer side of the base of the proximal phalanx of he great toe in common with the outer head of the flexor hallucis •revis and the transverse head.

Nerve-supply .—The deep division of the lateral plantar nerve.


Accessorius'


Flex. Dig. Long.

Medial Part of Flex. Hall. Brev.

M. Abd. Hall.

Oblique Head cf Adductor Hall.


Tendon of Peron. Long.


Base of Metatars. V. N. Plant. Lat.


FI. Dig. V. Brev. Abd. Dig. V.

Transverse Head of Adductor Hall.


Fig. 390.—The Third Layer of Plantar Muscles (Left Foot).


Action .—Adducts the great toe, and aids in flexing its metatarso>halangeal joint.

The muscle is obliquely disposed on the outer side of the flexor lallucis brevis.

Transverse Head (Transversus Pedis ) (Fig. 390)— Origin .—By three lips attached to the deep transverse ligament, and to the plantar igaments of the metatarso-phalangeal joints opposite the distal exremities of the three outer metatarsal bones.

Insertion .—It passes transversely across the distal end of the















A MANUAL OF ANATOMY


650

metatarsus, and ends in a tendon which is attached to the outer sid of the base of the proximal phalanx of the great toe in common wit the oblique head.

Nerve-supply.— The deep division of the lateral plantar nerve.

Action. —Adducts the great toe.

Flexor Digiti Minimi Brevis (Fig. 390)— Origin. —The base of th fifth metatarsal bone, but chiefly from the sheath of the tendon of th peroneus longus immediately behind it.

Insertion. —The outer side of the base of the first phalanx of th little toe in common with the abductor digiti minimi.

Some fibres may be attached to the shaft of the fifth metatarsal bone towarc its distal end. Such fibres represent an opponens minimi digiti, a muse normally present in the upper limb.

Nerve-supply. —The superficial division of the lateral plantar nerv

Action. —Flexes the metatarso-phalangeal joint of the little to* The muscle is a small fleshy slip which lies upon the plantar surfac of the fifth metatarsal bone, under cover of the abductor digiti minim It is liable to be mistaken for a plantar interosseous muscle, as it lie in close contact with the most lateral plantar interosseous.

The plantar triangle (Fig. 390) is a muscular triangle in connectio with the third layer of muscles, the boundaries of which are as follows Anterior or Base. —Transverse head of adductor hallucis. MedialOblique head of adductor hallucis. Lateral.- —Flexor digiti minin brevis. Floor. —Some of the plantar and dorsal interosseous muscle invested by the interosseous fascia. Roof. —The long flexor tendor and the lumbrical muscles. Contents. —A part of the plantar arteri; arch with some of its digital branches, especially the second and thire and a part of the deep branch of the lateral plantar nerve.

Fourth Layer. —The fourth layer consists of the interosseous musck occupying the metatarsus, and the tendons of the peroneus longus an tibialis posterior on the plantar aspect of the tarsus.

The interosseous muscles (Fig. 391) are seven in number, and ai arranged in two groups—three plantar and four dorsal. The plant; muscles are only seen in the -sole, but the dorsal muscles are als visible on the dorsum of the foot. The plantar aspects of the musck are covered by the thin interosseous fascia, which distally blends wit the deep transverse ligament (p. 671).

The three plantar interossei occupy the three outer intermetatars; spaces, and are inserted into the three outer toes. They are terme numerically the first, second, and third, from within outwards.

Origin .—From the three outer metatarsal bones, where they ai attached to the inner sides of the sharp ridges on the plantar aspeci of these bones. They also extend proximally on to the plantar aspeci of the bases of the metatarsal bones, and on to the sheath of the tendo of the peroneus longus. Each of the three muscles arises from th metatarsal bone of the toe into which it is inserted.

Insertion .—By tendon which is attached to the inner side of the ba^ of the proximal phalanx of the toe, and further extends on to th


THE LOWER LIMB 651

orsal aspect of the proximal phalanx, and there blends with the xtensor expansion.

The four dorsal interossei occupy the four intermetatarsal spaces, nd are termed numerically the first, second, third, and fourth, from dthin outwards. The first and second are both inserted into the econd toe, the third and fourth into the third and fourth toes respectively.

Origin .—Each muscle arises by two heads from the adjacent sides f the shafts of the two metatarsal bones between which it lies, but lore extensively from the metatarsal bone of the toe into which it is riser ted.

The inner head of the first dorsal interosseous is small, and is limited n its attachment to the proximal end of the first metatarsal bone, dhs muscle also arises from a band which crosses the proximal end


Fig. 391. —The Interosseous Muscles of the Right Foot.


A, plantar; B, dorsal.

if the first interosseous space, and arches across the deep plantar terminal branch of the dorsalis pedis artery. The third and fourth iorsal interossei extend proximally beyond the intermetatarsal spaces, and are attached to the sheath of the tendon of the peroneus longus.

Insertion .—Each muscle has a centrally placed tendon, on either side of which the obliquely disposed fibres of the two heads are implanted, the arrangement presenting a feather-like appearance. The central tendon is inserted distally to the base of the proximal phalanx. The first and second dorsal interossei are inserted on either side of the base of the proximal phalanx of the second toe; the third and fourth to the outer side of the base of the proximal phalanx of the third toe and of the fourth toe respectively.

Nerve-supply .—All the seven interosseous muscles are supplied by the lateral plantar nerve. The two muscles which occupy the fourth











652


A MANUAL OF ANATOMY


interspace—namely, the third plantar and the fourth dorsal—are si plied by the superficial division of the nerve, the remainder by its de division.

Action .—The axial line of the foot, away from which and towai which the toes diverge and converge respectively, passes through i second toe (cf. hand, where the axial line passes through the mid( finger). The three plantar interossei are adductors, pulling the thi outer toes inwards towards the line of the second toe. The four dor: interossei are abductors, the first and second pulling the second toe either side of its own line, the third and fourth pulling the third a: fourth toes outwards. The four dorsal interossei, together with t abductors of the two marginal digits (the abductor hallucis and t abductor digiti minimi), constitute a complete system of abducto pulling all the toes away from the axial line passing through the seco: toe.

The extent of abduction and adduction of the toes brought about by i interosseous muscles is very small as compared with the corresponding mo^ ments in the hand. In the opinion of some anatomists the interosseous muse as a group are concerned in approximating the metatarsal bones, and there accentuate the transverse arch of the foot in the metatarsal region.

The two plantar nerves, medial and lateral, are the terminal branch into which the posterior tibial nerve divides behind the lateral malleoli The lateral plantar is the larger of the two nerves, and accompani the medial plantar artery, the smaller of the two plantar arteries. T] lateral plantar nerve accompanies the lateral plantar artery.

The medial plantar nerve (Fig. 390) has a more extensive cutan ous, but a more limited muscular, distribution than the lateral plants At its commencement it lies deeply to the flexor retinaculum. As passes into the sole it is covered superficially by the abductor halluci It extends forwards near the inner side of the foot, and lies deeply the interval between the abductor hallucis and the flexor digitoru brevis, with the medial plantar artery lying on its inner side.

Branches.—Muscular branches supply the abductor hallucis ar flexor digitorum brevis.

Articular branches are distributed to tarsal and tarso-metatars joints.

Cutaneous branches become superficial between the abducb hallucis and flexor digitorum brevis, and are distributed to the sk: of rather more than the inner half of the sole.

The medial plantar nerve ends by dividing into four digital branche Tracing them from within outwards, the first digital nerve is di tributed to the inner side of the great toe, and supplies a branch to tl flexor hallucis brevis muscle. The second digital nerve supplies tl first lumbrical muscle, and opposite the cleft between the great an second toes divides into two collateral digital nerves, which suppl the adjacent sides of these two toes. The third digital nerve similar! divides into two collateral branches, which supply the adjacent side of the second and third toes. The fourth digital nerve communicate


THE LOWER LIMB


653


th the digital branch of the lateral plantar nerve lying on its outer le, and ends by dividing into two collateral branches supplying the jacent sides of the third and fourth toes. On the sides of the toes e nerves lie superficially to the digital arteries. They supply articular anches to the digital joints, and cutaneous branches to the plantar id dorsal surfaces of the toes. Finally, each terminates in two anches—one to the matrix of the nail, and the other to the pulp of e toe. The branches of the digital nerves are beset with numerous icinian bodies.

Summary of the Medial Plantar Nerve.—Muscular branches to four muscles : e flexor digitorum brevis, two muscles of the great toe (the abductor and the xor brevis), and the first lumbricalis. Cutaneous branches to the skin of the


Fig. 392. —Diagram of the Nerves of the Foot (Plantar Aspect).

mer half of the sole and of the inner three and a half toes. Articular branches ) the tarsal, metatarsal, and digital joints.

The distribution of the medial plantar nerve corresponds closely with that 1 the median nerve in the hand.

The lateral plantar nerve passes downwards from under cover of tie flexor retinaculum, and gains the inner side of the hinder part of tie sole, where it lies deeply to the abductor hallucis. Thence it crosses tie foot, passing obliquely forwards and outwards towards the Tominent base of the fifth metatarsal bone. In this part of its course

lies between the flexor digitorum brevis superficially and the flexor ccessorius deeply, and is accompanied by the lateral plantar artery, diich lies to its outer side. Finally, it lies deeply in the interval •etween the flexor digitorum brevis and the abductor digiti minimi, diere it divides into two terminal branches, superficial and deep.






654


A MANUAL OF ANATOMY


The Branches of the Trunk. —Muscular to the flexor accessoriu: and the abductor digiti minimi; articular to the calcaneo-cuboid joint cutaneous branches become superficial between the flexor digitorun brevis and the abductor minimi digiti to supply the skin of the oute: half of the sole; and two terminal branches.

Of the two terminal branches, the superficial branch divides int( two digital nerves, outer and inner. The outer digital nerve is dis tributed to the outer side of the little toe, and also supplies the flexoi digiti minimi brevis and the interosseous muscles of the fourth inter space (the fourth dorsal and third plantar). The inner digital nerv< communicates with the most lateral digital branch of the media plantar nerve, and divides into two collateral digital branches, whicl supply the adjacent sides of the third and fourth toes. In their course and distribution the digital branches of the superficial division of the lateral plantar nerve resemble those of the medial plantar.

The deep branch crosses the foot from the outer side towards the inner side, and lies deeply in the plane between the third and fourtl layers of muscles. On its deep aspect are the bases of the metatarsa bones and the interosseous muscles, superficially to it are the oblique head of adductor hallucis, and in the plantar triangle (p. 650) the flexoi tendons, together with the lumbrical muscles. It accompanies the plantar arterial arch.

Branches.—Muscular branches supply all the interosseous muscles (with the exception of the two occupying the fourth interosseous space); the outer three lumbricales and the adductor hallucis, and twe muscles of the great toe.

The nerve to the second lumbricalis passes forwards deeply to the transverse head of adductor hallucis, winds round the distal edge of this muscle, and finall) takes a recurrent course to enter the deep aspect of the lumbrical muscle.

Articular branches supply the tarsal and metatarsal joints.

Minute perforating branches pass upwards through the proxima' ends of the intermetatarsal spaces, and join the interosseous branches of the anterior tibial nerve.

Summary of Lateral Plantar Nerve.—Muscular branches to the flexor acces sorius, the two short muscles of the little toe, all the interossei, the outer thret lumbricales, and the adductor hallucis. Cutaneous branches to the skin of thf outer half of the sole and of the outer one and a half toes. Articular branches tc the tarsal, metatarsal, and digital joints. Perforating branches join the inter osseous nerves on the dorsum of the foot.

The distribution of the lateral plantar nerve closely corresponds with thal of the ulnar nerve in the hand.

Plantar Arteries. —The medial and lateral plantar arteries are the terminal branches into which the posterior tibial divides under cover of the flexor retinaculum. The medial plantar is much the smaller of the two. Each vessel is accompanied by the corresponding plantar nerve.

The medial plantar artery (Fig. 390) first passes downwards deeply to the abductor hallucis, and then passes directly forwards near the


THE LOWER LIMB


655


mer side of the foot, lying deeply in the interval between the abductor allucis and flexor digitorum brevis. It is accompanied by the medial lantar nerve, which lies on its outer side. It usually ends by anastolosing with the first dorsal metatarsal artery on the inner side of the reat toe.

Branches. —In addition to muscular branches which supply the ruscles on the inner side of the foot, and cutaneous branches which ccome superficial between the abductor hallucis and flexor digitorum revis, and supply the skin of the inner half of the sole, it gives off he following branches:

Articular to the joints on the inner side of the foot.

A variable number of small superficial digital branches which ccompany the digital branches of the medial plantar nerve, and livide into collateral branches which supply the toes.

These digital branches are very variable and frequently absent. When resent, they anastomose with the digital branches of the plantar arch.

The medial plantar artery communicates with the medial tarsal ranches of the dorsalis pedis artery by twigs which wind round the nner border of the foot deeply to the abductor hallucis.

The lateral plantar artery (Fig. 393) is much larger than the medial dantar. It ends at the proximal end of the first intermetatarsal space )y joining the deep plantar of the dorsalis pedis artery.

At its commencement it lies on the inner side of the calcaneum, being

overed superficially by the abductor hallucis. Thence it passes )bliquely forwards and outwards across the hinder part of the sole owards the prominent base -of the fifth metatarsal bone on the outer fide of the foot. In this the first or superficial part of its course it ies between the first and second layers of muscles, the flexor digitorum )revis covers it superficially , the flexor accessorius is on its deep aspect; t is accompanied by the lateral plantar nerve, which lies on its inner fide. Gaining the interval between the flexor digitorum brevis and

he abductor digiti minimi, its direction suddenly changes, and it crosses the foot for a second time. It winds round the outer edge of

he flexor accessorius, and crosses the base of the metatarsus from the niter side of the foot towards the inner, lying deeply between the third md fourth layers of muscles. In this the second or deep part of its course the proximal ends of the metatarsal bones and the interosseous muscles are on its deep aspect; the oblique head of adductor hallucis md, in the plantar triangle (p. 650), the flexor tendons with the lumbricales are superficial to it. It is accompanied by the deep branch of the lateral plantar nerve. It ends at the proximal end of the first intermetatarsal space, where it joins the terminal branch of the dorsalis pedis artery, which here passes downwards from the dorsum of the toot into the sole. The second or deep part of the lateral plantar artery, together with the dorsalis pedis artery, complete the plantar arch.

Branches of the First Part.—Muscular branches to the muscles with which it comes into relation. Two or three branches traverse the


A MANUAL OF ANATOMY


656


abductor hallucis muscle and ramify over the heel, where they ana tomose with the medial calcanean branch of the posterior tibia! artei and the lateral calcanean branches of the peroneal artery. Cutaneoi branches become superficial between the abductor digiti minimi an


/ Medial Calcaneal Artery


Posterior Tibial Artery


Lateral Plantar Artery_


Peroneus Brevis—I


Posterior Perforating' Artery

First Digital Artery Plantar Arch,


Second Digital A. Third Digital A. Fourth Digital A.


Anterior Perforating Artery


Medial Plantar Artery


_Tibialis Posterior


• Flex. Digitorum Longus Flex. Hallucis Longus •Flex. Accessorius


.-Tendon of Abd. Hallucis


Deep Plantar Branch of • Dorsalis Pedis Artery Communicating Branch


_ First Plantar Metatarsal Arte


Fig. 393. —The Plantar Arteries (Left Foot) (after L. Testut’s

‘ Anatomie Humaine/).

flexor digitorum brevis. They supply the skin of the outer half 0 the foot.

Small twigs wind round the outer border of the foot, and anasto mose with the tarsal and arcuate branches of the dorsalis pedis artery













THE LOWER LIMB


657


The plantar arch (Fig. 393) is an arterial arcade which results from he junction of the deep part of the lateral plantar with the dorsalis edis artery. The convexity of the arch, is towards the toes.

Branches of the Plantar Arch.—Articular branches arise from the oncavity of the arch, and pass backwards to supply the tarsal joints.

Three perforating arteries pass upwards through the proximal ends f the three outer intermetatarsal spaces, and between the two heads f the corresponding dorsal interosseous muscles. On the dorsum of he foot they join the dorsal metatarsal branches of the arcuate artery.

Four digital arteries arise from the convexity of the arch. The first rosses the fifth metatarsal bone and the flexor digiti minimi brevis; it 3 distributed to the outer side of the little toe. The second, third, ,nd fourth pass forwards in the three outer intermetatarsal spaces, diere they lie on the interosseous muscles. They pass deeply to the ransverse head of adductor hallucis, and divide near the clefts of the oes into collateral digital arteries. The second supplies the adjacent ides of the fourth and fifth toes; the third is similarly distributed to he third and fourth toes; the fourth to the second and third toes.

The first and second digital arteries often arise from the plantar arch by a

ommon trunk. The two arteries, one on either side of the toe, supply branches to he skin and the fibrous sheaths of the tendons. They are connected ogether, on the plantar aspects of the phalanges, by transverse comnunications, from which branches to the synovial sheaths, the flexor

endons, and the interphalangeal joints are derived. Dorsal branches Dass to the dorsal aspect of the toe, and anastomose with the dorsal ligital arteries. The largest dorsal branches form an arterial arcade it the root of the nail, numerous branches of which supply the nail bed. rhe two arteries end by joining one another on the distal phalanx to

orm an arch from which branches are distributed to the pulp of the toe. The first plantar metatarsal artery passes forwards in the first internetatarsal space, where it lies on the first dorsal interosseous muscle md deeply to the oblique head of adductor hallucis. It divides into lwo branches; one passes inwards deeply to the tendon of the flexor lallucis longus and the flexor hallucis brevis, and is distributed to the nner side of the great toe. The other divides into two collateral digital irteries, which supply the adjacent sides of the great and second toes.

The arteries of the foot are much more constant than those of the hand.

Varieties. —The medial plantar artery is sometimes very small, and may end Ln the flexor hallucis brevis. In other cases it is large, and may replace the irteria princeps hallucis, and furnish the digital branches for both sides of the ^reat toe and the inner side of the second toe. In rare cases the medial plantar artery communicates with the lateral plantar, with which it forms a superficial plantar arch. In such cases the digital arteries arise from this arch.

The lateral plantar artery may be diminished in size to such an extent that it may take no share in forming the plantar arch. Such deficiency is compensated for by enlargement of the plantar branch of the dorsalis pedis artery.

The perforating branches of the plantar arch are sometimes enlarged, and furnish the dorsal interosseous arteries on the dorsum of the foot.


4 2



6 5 8


A MANUAL OF ANATOMY


Fig. 394.—Superficial Lymphatics of the Lower Limb.


Lymphatic Vessels of the Lower Limb.

The lymphatic vessels of the limb are disposed two sets, superficial and deep. The two sets are n to be regarded as absolutely independent one of tl other, as in certain situations they freely communica with each other. It may be taken as a general ru that the lymphatic trunks which drain the superfici parts of the limb follow the chief subcutaneous vein while the deep vessels follow the main arteries of tl limb.

Superficial Lymphatics. —On the dorsum of tl foot is a network of vessels into which the lymphati of the toes drain, and which also receives the supe ficial lymphatics of the plantar region, some of whi( reach it by passing upwards in the interdigital space others by winding round the margins of the foe This dorsal plexus is drained by two sets of larg lymphatic vessels which follow the long and sho saphenous veins respectively. The vessels followii the short saphenous vein receive tributaries drainii the outer side and back of the leg; they eventual join the popliteal glands (p. 551). Those followii the long saphenous vein receive vessels from the inn side and front of the leg, and in the region of tl knee are joined by some of the efferent vessels of tl popliteal glands. Above the knee they receive mo of the superficial lymphatic vessels of the thigh, ar end in the medial set of superficial inguinal glam (p. 358). Some of the superficial lymphatic vessels the upper part of the thigh and those of the glute region join the superficial inguinal glands direct (p. 358).

The deep lymphatics on the dorsum of the fo< follow the dorsalis pedis artery, those in the so accompany the two plantar arteries. They are co: tinuous with vessels which accompany the lap arteries of which the foot arteries are branches. 1 the leg three chief sets of lymphatic vessels accor pany the two tibial and the peroneal arteries. Tl anterior tibial set receives the deep lymphatics fro: the dorsum of the foot and the front of the leg; the join the anterior tibial gland, the efferent vessels < which pass to the popliteal glands (p. 551). Tl posterior tibial set receives the deep lymphatics < the sole of the foot, and together with the perone set drain the back of the leg; they join the poplite glands (p. 551). Some of the efferent vessels of tl popliteal glands join the superficial lymphatics accon panying the long saphenous vein; most of the: ascend and join the deep lymphatic vessels whic accompany the femoral artery, drain the deep par of the thigh, and end in the deep inguinal glands.

The efferent vessels of the inguinal glands, boi superficial and deep, are described on p. 358. Tl deep lymphatics of the buttock accompany the ii ferior and superior and gluteal arteries, pass throug the greater sciatic notch, and join the internal ilk glands.













THE LOWER LIMB


659


THE TIBIO-FIBULAR JOINTS.

Between the upper and lower ends of the tibia and fibula are uperior and inferior tibio-fibular joints. Intermediately is an extended yndesmosis between the shafts of the two bones, which are connected ogether by the interosseous membrane.

Superior Tibio-fibular Joint. —In this joint the articular surface >n the upper aspect of the head of the fibula is applied to that on the nferior aspect of the external tuberosity of the tibia. The joint is unrounded by a capsular ligament in which anterior and posterior igaments may be distinguished. The fibres of the two ligaments )ass obliquely upwards and inwards from the head of the fibula to he lateral condyle of the tibia. The anterior ligament is intimately issociated with the tendon of the biceps, which contributes materially

o the strength of the joint. The tendon of the popliteus lies superficially o the posterior ligament. The synovial cavity is usually independent of that of the kneeoint, but sometimes communicates with it indirectly by means of a mall deficiency in the posterior ligament, whereby the synovial memDrane is continuous with the synovial sheath of the tendon of the popliteus (p. 641).

Nerve-supply. —The lateral inferior genicular and recurrent geniular branches of the lateral popliteal nerve.

Movements. —Slight gliding movements in the plane of the articular suraces.

Inferior Tibio-fibular Joint. —The opposed surfaces of the lower mds of the tibia and fibula are for the most part rough, and are conlected together by an interosseous ligament. The extreme lower Darts of the two surfaces, for a distance of from 1 to 2 mm. only, are n contact with each other, and are coated with hyaline cartilage, rhe very limited joint cavity is continuous with that of the ankleoint. The ligaments are anterior inferior and posterior inferior tibio-fibular, interosseous, and transverse tibio-fibular.

The anterior inferior tibio-fibular ligament (Fig. 398) is thick and strong, and passes obliquely downwards and outwards from the tibia to the fibula. It is related in front to the peroneus tertius, and behind to the interosseous ligament.

The posterior inferior tibio-fibular ligament (Fig. 396) is thicker md stronger than the anterior. It also passes obliquely downwards md outwards from the tibia to the fibula.

The interosseous ligament consists of short fibres, which pass very Dbliquely from the rough triangular surface at the lower ends of the tibia to the corresponding surface of the fibula. It is continuous ibove with the interosseous membrane. Anteriorly and posteriorly its lower part is related to the anterior and posterior inferior tibiofibular ligaments.


66 o


A MANUAL OF ANATOMY


The transverse ligament (Fig. 395) lies deeply to the postern ligament, and fills in a slight interval between the lower ends of tt tibia and the fibula. It forms the posterior limit of the inferior tibi< fibular joint cavity, is in contact with the talus below, and is continuoi with the interosseous ligament above. It completes the upper articuh surface of the ankle-joint. It is remarkable for containing yelio elastic fibres, which account for its yellowish colour.

Nerve-supply.— The anterior tibial nerve.

The movements are very limited, a slight amount of gliding taking pla< between the cartilage-clad articular surfaces. When the ankle-joint is flext the two malleoli are forced apart by the talus, and the transverse ligament is pi on the stretch. In this position a fat-laden fold of synovial membrane occupi the interval between the articular surfaces. When the ankle-joint is extend* a narrower part of the talus is interposed between the two malleoli (p. 36$ The resiliency of the elastic transverse ligament now comes into play, pul

Ant. Tib.-fib. Lig.

/

/

/


. _ Lat. Malleolus


—-Trans. Tib.-fib. Lig.


^ Post. Tib-fib. Lig.

Fig. 395. —The Upper Articular Surfaces of the Ankle-Joint

VIEWED FROM BELOW.

the lower ends of the tibia and fibula together, and keeps the two malleoli close! applied to the lateral aspects of the talus, while the other ligaments of the joir (anterior, posterior, and interosseous) are relaxed.

Intermediate Tibio-fibular Syndesmosis. —The interosseous mem brane extends from the lateral border or interosseous ridge of tb tibia to the antero-medial border or interosseous ridge of the fibuk The direction of the fibres is chiefly downwards and outwards fror the tibia to the fibula, but a few pass in the opposite direction. A its upper end is an opening with a concave lower margin for the passag of the anterior tibial vessels and the efferent lymphatic vessels of th anterior tibial gland. Below it is continuous with the interosseou ligament, and has a small opening for the passage of the peroneal vessel? All the extensor muscles on the front of the leg are attached to it anterior surface; the tibialis posterior is attached to its posterior surfact Nerve-supply. —-The interosseous branch of the nerve to the popliteu muscle (p. 550).






THE LOWER LIMB


661


THE ANKLE-JOINT.

The articular surfaces of the joint are furnished by the tibia, fibula, nd talus. The lower ends of the tibia and fibula provide a morticeke socket, formed by the inferior articular surface of the tibia together uth the transverse ligament above, and the articular surfaces of the wo malleoli on either side (Fig. 395). Into this socket the upper part f the talus fits like a wedge. The convex upper surface of the astraglus is applied to the inferior surface of the tibia, while the two lateral urfaces of the bone are in contact with the two malleoli (Fig. 396). he upper articular surface of the talus is wider in front than behind,


Fig. 396.—The Right Ankle-Joint (Posterior View). The posterior ligament has been removed.


md on its outer bevelled edge the transverse ligament of the inferior

ibio-fibular joint plays in the flexion and extension movements of the joint. The joint is surrounded by a capsular ligament in which m anterior, a posterior, and two lateral ligaments may be distinguished.

The anterior ligament is exceedingly thin, consisting of not much more than a few scattered fibres which clothe the synovial membrane. Above it is attached to the anterior margin of the lower end of the tibia and to the anterior inferior tibio-Lbular ligament, below to the talus immediately in front of its upper articular surface.

The posterior ligament is also very thin, and chiefly consists of transverse fibres. It is attached above to the posterior aspect of the lateral malleolus medial to the peroneal groove, the posterior inferior tibio-fibular ligament, and the posterior margin of the inferior surface










662


A MANUAL OF ANATOMY


of the tibia. Below it is attached to the posterior margin of the upp articular surface of the talus.

The medial ligament (Fig. 397) is also known inappropriately as t] deltoid ligament. It is thick, flat, and quadrangular. Above it attached to the lower margin of the medial malleolus. The anteri fibres are comparatively thin, and pass obliquely downwards ai forwards to the tuberosity of the navicular bone and the plant calcaneo-navicular ligament; the middle fibres are vertical, and a attached below to the sustentaculum tali; the posterior fibres, sho and thick, incline downwards and backwards to the talus, and exter backwards as far as the inner tubercle on the posterior aspect of t] bone. In addition, there is a deep band of fibres which are attache to the tip of the medial malleolus above and the inner side of tl talus below.


Fig. 397.— Ligaments of the Right Foot (Medial Aspect).


The lateral ligament consists of three distinct bundles—anterio middle, and posterior.

The anterior talo-fibular ligament (Fig. 398) extends forwards an slightly inwards from the lower part of the anterior border of tt lateral malleolus to the outer surface of the neck of the talus.

The calcaneo-ftbular ligament (Fig. 398) is the longest of the threi It is attached above to the tip of the lateral malleolus, from which : passes obliquely downwards and backwards to a tubercle on the oute surface of the calcaneum behind and above the peroneal tubercle.

The posterior talo-fibular ligament (Fig. 396) is the strongest an thickest of the three. It is attached to the malleolar fossa, which : immediately behind the articular facet on the inner surface of th lateral malleolus. Thence it passes almost directly inwards to th outer tubercle on the posterior aspect of the talus.




THE LOWER LIMB


663


The synovial membrane is loose, and lines the deep surfaces of the ligaments. It also invests pads of fat at the front and back of the joint, where synovial folds project between the articular surfaces of the talus and tibia to a greater or less extent according to the position of the joint. It is also prolonged upwards, and lines the anterior and posterior ligaments of the inferior tibio-fibular joint.

Relations of the Ankle-Joint. —In front, from within outwards, are the tendons of the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and peroneus tertius, with the anterior tibial vessels and nerve lying between the extensor hallucis longus and extensor digitorum longus. Behind, from within outwards, are the tendons of


Peroneus Longus ;

Peroneus Brevis


Fig. 398.—Ligaments of the Right Inferior Tibio-fibular, Ankle, Tarsal, and Tarso-metatarsal Joints (Lateral Aspect).


the tibialis posterior, flexor digitorum longus, and flexor hallucis longus, with the posterior tibial vessels and nerve lying between the flexor digitorum and flexor hallucis longus. More superficially, and separated from the joint by a considerable amount of fat, are the tendo-calcaneus and the tendon of the plantaris. Laterally the peroneal tendons are superficial to the calcaneo-fibular ligament. Medially the tendons of the tibialis posterior and flexor digitorum longus cross the deltoid ligament superficially.

Nerve-supply. —The anterior and posterior tibial nerves.

Movements. —The chief movements at the ankle-joint are flexion and extension. It is important to remember that the habitual position of the foot is at right angles to the leg, and is really one of hyperextension. Consequently, bending the foot or diminishing the angle between it and the leg (flexion) is









664


A MANUAL OF ANATOMY


brought about by the extensor muscles on the front of the limb, while tl flexor muscles are concerned in straightening the foot or widening the ang' between it and the leg (extension). In the extended position, when the narrow< part of the articular surface of the talus occupies the tibio-fibular socket, very limited amount of lateral movement is possible. In flexion the broa anterior part of the superior articular surface of the talus is carried backwarc into the narrow posterior part of the tibio-fibular socket, and lateral movemer is then impossible. Flexion is chiefly limited by the posterior parts of the tw lateral and deltoid ligaments, and extension by the anterior parts of thej ligaments. The range of movement in flexion and extension is about 90 degree: and takes place round a transverse axis passing through the body of the talus.

In the standing posture the line of the centre of gravity falls in front of th axis of movement at the ankle-joint. There is thus a tendency to flex the join which is counteracted by contraction of the calf muscles.


THE JOINTS OF THE FOOT.

The joints of the foot are tarsal, tarso-metatarsal, intermetatarsa metatarso-phalangeal, and interphalangeal.

The tarsal joints may be further subdivided into:

1. Posterior tarsal joints, between the talus and calcaneum.

2. Mid-tarsal joints, between the talus and calcaneum behim and the navicular and cuboid in front.

3. Anterior tarsal joints, between the navicular, the three cunei forms, and the cuboid.

The Posterior Tarsal Joints.

Talo-calcaneal Joints. —Between the talus above and the calcaneur below are two joints, anterior and posterior. The joints are separate* from each other by the interosseous ligament, which fastens the tw< bones together and is a ligament common to the two joints.

The posterior talo-calcaneal joint is surrounded by a capsular liga ment in which special thickenings are known as the interosseou posterior, medial, and lateral ligaments.

The interosseous ligament is the strongest and most importan ligament connecting the talus to the calcaneum. It is attached to th interosseous grooves on the opposed surfaces of the two bones. It i very strong, and consists of both vertical and oblique fibres. Laterally it is intimately associated with the stem of the extensor retinaculun (p. 603).

The posterior talo-calcaneal ligament (Fig. 397) extends from th< outer tubercle on the back of the talus to the adjacent part of th calcaneum. It is a short but relatively broad band.

The medial talo-calcaneal ligament (Fig. 396) passes from the inne: tubercle on the back of the talus to the hinder end of the sustentaculmr tali of the calcaneum.

The lateral talo-calcaneal ligament (Fig. 398) is a short narrow banc which extends obliquely downwards and backwards from the outei surface of the talus immediately below the fibular facet to the adjacent part of the calcaneum. It is situated deeply to, but is slightly farther


THE LOWER LIMB


665

awards than, the middle fasciculus of the lateral ligament of the ikle-joint.

The anterior talo-calcaneal joint plays an important part in the ilo-calcaneo-navicular joint, with which it will be considered.

Mid-Tarsal Joints.

The talo-calcaneo-navicular joint is the largest and most important f all the tarsal joints. The articular surfaces consist of the more or

ss spherical head of the talus, which fits into a cup provided by the rticular surface on the upper aspect of the calcaneum, in front of the iterosseous groove, and the concave articular surface on the posterior nrface of the navicular bone. The articular cup is completed by two gaments, the calcaneo-navicular part of bifurcated ligament and the lantar calcaneo-navicular ligament, which bind the two bony contituents of the cup together.

The plantar calcaneo-navicular ligament {spring ligament ), or, as it

hould be more properly called, the infero-medial calcaneo-navicular gament, fills in a triangular interval between the calcaneum and the lavicular bone, and completes the floor of the cup (Fig. 399). It also xtends upwards on the inner aspect of the joint. It is attached behind 0 the sustentaculum talis, and in front to the plantar surface, to the uberosity, and slightly to the dorsal surface of the navicular bone, die upper surface of the lower part of the ligament is thickly coated nth hyaline cartilage, and impresses a well-defined triangular area >n the head of the talus; this area is intermediate in position between he articular surfaces for the calcaneum and the navicular bone Fig. 399). The upper or inner part of the ligament is a curved fibrous >and closely applied to the head of the talus and forms the inner wall )f the articular cup. The superficial aspect of the ligament is closefy elated to the tendon of the tibialis posterior. Some of the anterior ibres of the deltoid ligament of the ankle-joint are attached to it Fig. 397).

The bifurcated ligament (Fig. 399) is attached behind to the upper surface of the front part of the calcaneum. It divides into two bands: he outer passes forwards to the cuboid; the inner, or calcaneo-navicular l .'•art, passes obliquely forwards and inwards to the navicular bone. It completes the outer wall of the articular cup for the reception of the lead of the talus.

The head of the talus is retained in its articular cup by two liganents, which fasten the talus to the calcaneum and to the navicular lone respectively.

The former is the talo-calcanean interosseous ligament, which completes the joint behind and separates it from the posterior talo-callanean joint (p. 664).

Medial and lateral talo-calcanean ligaments, sometimes described in connection with the anterior talo-calcanean joint, are only collateral parts of the interosseous ligament, with which they are continuous.


666


A MANUAL OF ANATOMY


The latter is the dorsal talo-navicular ligament, a thin fibrous she( on the dorsal or upper aspect of the joint. It is attached behind i the upper surface of the head of the talus close to the edge of th articular surface, from which it sweeps downwards and forwards t the upper surface of the navicular bone. Its collateral margins ai adherent to each side of the bifurcated ligament. The interosseoi and the dorsal talo-navicular ligaments form together an almost con plete capsule surrounding the joint.

From the foregoing description it may be realized that the anterior tal< calcanean joint is a part of the general talo-calcaneo-navicular joint, and shou] not be described independently.


Calcaneo-navicular part of Bifurcated Ligament


Line of attachment of Dorsal Talo-navic. Lig, Facet for Plantar Calc.-navic. Lig.


Bifurcated

Ligament


' Tendon of Tibialis Posterior

V

Plantar Calcaneo-navicular Ligament

\

’ Interosseous Ligament (cut)


Fig. 399.— The Plantar Calcaneo-navicular Ligament of the

Left Foot (Superior View).


The calcaneo-cuboid joint is the outer of the two mid-tarsal joints In this joint the articular surface on the anterior aspect of the calcaneum is applied to the posterior articular surface of the cuboid the opposed surfaces are somewhat saddle-shaped. The ligament' connecting the calcaneum and the cuboid are dorsal calcaneo-cuboid calcaneo-cuboid part of bifurcated ligament, and two plantar.

The dorsal calcaneo-cuboid ligament (Fig. 398) is a flattened band which passes between the adjoining surfaces of the calcaneum and cuboid. Some of its lateral fibres are attached to the outer surface oi the calcaneum.

The calcaneo-cuboid part of bifurcated ligament (Fig. 399) passes forwards from the calcaneum, and is attached to the supero-media] aspect of the cuboid.










THE LOWER LIMB


667


The two plantar ligaments are known as the long and the short. The latter is almost completely under cover of the former.

The long plantar ligament (Fig. 370) is by far the longest ligament in the foot. It clothes and is adherent to all the plantar surface of the calcaneum in front of the two tubercles at the hinder part of the bone. From the calcaneum it passes on to the plantar aspect of the cuboid, where it is adherent to the prominent ridge behind the peroneal groove. It passes forwards across the groove, and finally subdivides into slightly diverging bands, which are attached to the bases of the second,


Groove for Flexor Hallucis Longus


Sustentaculum Tali


Calcaneo-navicular


Tibialis Posterior- 1

Plantar Calcaneonavicular-^ Ligament


Short Plantar Ligament

Plantar Naviculo-cuboid Ligament Navicular Bone

Plantar Naviculo-cuneiform / ' Ligaments 1 .


Medial Cuneiform Bone

Insertion of Peroneus Longus

Capsule of ist Tarso-. metatarsal Joint


- Calcanean Tuberosity


~ Long Plantar Ligamen


“Peroneus Longus Peroneus Brevis


- Plantar Cuboideo-metatarsal Ligament


Fig. 400.—Ligaments of the Right Foot (Plantar Aspect),


third, and fourth metatarsal bones. The ligament converts the peroneal groove into a canal in which the tendon of the peroneus longus is contained. '

The short plantar ligament is the shorter and thicker of the two plantar ligaments, and its fibres are more obliquely disposed. It extends forwards from the tubercle at the front end of the plantar surface of the calcaneum to the cuboid, where it is attached to the ridge orming the posterior limit of the peroneal groove and the surface of bone behind it.



































668


A MANUAL OF ANATOMY


Fig. 401.—Deeper Ligaments in the Sole.

The long plantar ligament (LP) has been removed, with other superficial bands, and peroneus longus tendon (P) turned aside. Short plantar (SP) and calcaneo-navicular (CN) fibres are seen, and other bands of the longitudinal group anterior to the navicular, in the form of naviculocuneiform and cuneiform-metatarsal; some of these fibres (NCU) are very oblique. Transverse fibres are in the anterior tarsal region. Cubo-navicular (SC), cubo-cuneiform (CCU), and intercuneiform bands comprise these. In front of them is the tarsometatarsal region, with corresponding ligaments (TM); one of these bands runs transversely between the cuneiforms and the fifth metatarsal, and is evidently part of the transverse arch mechanism, although it is actually tarso-metatarsal.


The Naviculo-cuboid Ligaments

—The navicular and the cuboid which are only occasionally ir contact with each other, are bounc together by three strong liga ments—dorsal, plantar, and in terosseous. The dorsal and plan tar ligaments are more or les< transverse.

The dorsal ligament (Fig. 398 is triangular with its base on the cuboid.

The plantar ligament (Figs 400 and 401) is very otter double.

The interosseous ligament i<

very strong and thick. It consist* of short fibres, which, as a rule completely fill the interval between the adjacent surfaces of the two bones.

The cuboid and the naviculai are very firmly knit together by these ligaments, and the movements between them are so slight as to be inappreciable.

Movements at the Mid-tarsal Joints.

—The cuboid and navicular, carrying the distal part of the foot with them ; move as one bone, and with a considerable amount of freedom, on the rounded head of the talus and the anterior articular surface of the calcaneus. Slight movements of extension and flexion take place in association with movements of the anklejoint. Extension occurs when the ankle is flexed, the opposite movement when it is extended. The chief movements are adduction and abduction, whereby the foot is carried inwards and outwards, and rotation movements, whereby the foot is everted and inverted. Slighter displacements in the two talo-calcanean joints take a share in these movements.


Anterior Tarsal Joints.

The cuneo-navicular joint is the joint between the navicular behind and the three cuneiforms in front. It is provided with dorsal, plantar, and medial ligaments.







THE LOWER LIMB 669

The dorsal ligaments, three in number, pass obliquely forwards and outwards from the navicular to the three cuneiforms.

The plantar ligaments have the same general direction as the dorsal, but are more closely packed together.

The medial ligament is very thick and strong. It extends from the tuberosity of the navicular bone to the inner surface of the medial cuneiform. It is usually continuous above and below with the innermost dorsal and plantar ligaments.

Intercuneiform and Cuneo-cuboid Joints. —The three cuneiform bones and the cuboid are bound together by dorsal, interosseous, and plantar ligaments.

The three dorsal ligaments are relatively narrow transverse bands which connect the four bones together.

The three interosseous ligaments (Fig. 402) are very thick and strong. They consist of short fibres, which connect the non-articular areas of the adjacent surfaces of the four bones.

The plantar ligaments are two in number. One very thick band extends obliquely forwards and outwards from the medial to the intermediate cuneiform. The other is a weaker band which passes obliquely forwards and inwards from the cuboid to the lateral cuneiform.

The movements which take place in the anterior tarsal joints are very limited and are confined to slight gliding movements. They confer elasticity to the anterior part of the tarsus, and are also associated with alterations which occur in the arches of the foot.

The Tarso-metatarsal Joints.

The joint line between the tarsus and metatarsus slopes obliquely across the foot, the inner end being about three-quarters of an inch farther forwards than the outer. This line is interrupted opposite the second metatarsal bone, the base of which is wedged into a morticelike socket provided by the three cuneiform bones (Fig. 402).

Between the tarsus and metatarsus are three distinct joint cavities (Fig. 402): A medial between the medial cuneiform and the first metatarsal; an intermediate between the three cuneiforms and the second and third metatarsals; a lateral or cuboideo-metatarsal between the cuboid and the fourth and fifth metatarsals.

The joints are provided with dorsal, plantar, and interosseous ligaments.

The medial tarso-metatarsal joint, between the medial cuneiform and the first metatarsal, has a capsular ligament which is somewhat deficient laterally, and is stronger below and medially than elsewhere. Its upper and lower parts are usually distinguished as plantar and dorsal ligaments.

The Dorsal Ligaments. —The second metatarsal is provided with three dorsal ligaments, which converge from the three cuneiform bones on to its base. The bases of the three outer metatarsals are fastened to the lateral cuneiform and to the cuboid by one dorsal ligament in each case.


670


A MANUAL OF ANATOMY


The plantar ligaments are less regular than the dorsal. An obliqu band passes obliquely outwards and forwards from the medial cunei form to the bases of the second and third metatarsals. The inter mediate cuneiform and the second metatarsal, the lateral cuneiforn and the third metatarsal, the cuboid and the two outer metatarsals are all connected together by single bands. The plantar ligament are supplemented by the long plantar ligament, which is usually attached to the bases of the second, third, and fourth metatarsa bones, and by tendinous slips of the tendon of the tibialis posterior which are also attached to the bases of the second, third, and fourt] metatarsals (p. 622).

The interosseous ligaments are three in number, two of them bein{ attached to the second metatarsal bone.

The medial is the thickest and strongest. It extends obliqueh forwards and outwards from the outer side of the medial cuneiforn


M.

.M.


.M.


.M.


M.

Fig. 402.—The Synovial Cavities of the Tarsal and Tarso-metatarsal Joints.

to the adjacent side of the base of the second metatarsal. The intermediate, the weakest and least constant, extends from the latera] cuneiform to the outer surface of the base of the second metatarsal The lateral extends from the lateral cuneiform to the outer side of the base of the third metatarsal.

The interosseous ligaments, with the exception of the. internal, are variable Occasionally weak interosseous bands pass from the lateral cuneiform or the cuboid to the fourth metatarsal.

Of all the metatarsals, the second is most firmly fastened to the tarsus. Its base is wedged into the socket provided by the three cuneiform bones, and it is held in place by a larger number of ligaments than any other metatarsal bone.

Nerve-supply. —The anterior tibial and the two plantar nerves.

The movements at the tarso-metatarsal joints are slight movements of flexion

and extension which occur in changes affecting the arches of the foot. Slight lateral movements may take place in the first and the two outer metatarsals, which are more movable on the tarsus than the second and third. The second metatarsal bone is almost immovable on the tarsus.






THE LOWER LIMB


671


The Intermetatarsal Joints.

The bases of all the metatarsal bones, with the exception of the rst, are closely approximated, and the joints between them are rovided with dorsal, plantar, and interosseous ligaments.

In rare cases a joint exists between the first and second metatarsal bones.

The dorsal and plantar ligaments, in each case three in number, re transverse bands which unite the adjoining bases of the four outer letatarsal bones together. The dorsal ligaments are thin, while the lantar are relatively much thicker and stronger.

The interosseous ligaments are three dense and very strong fibrous ands, which are nearer to the plantar ligaments than to the dorsal, 'hey connect the rough non-articular lateral surfaces of the metarrsal bases together (Fig. 402).

The synovial cavities are continuous with those of the tarso-metaarsal joints. Those between the second and third and between the hird and fourth metatarsal bones are continuous with the middle arso-metatarsal joint cavity; that between the fourth and fifth metaarsal bones is continuous with the cuboideo-metatarsal cavity Fig. 402).

The movements are very slight gliding movements, which are associated fith variations in the arches of the foot.

Crossing the plantar aspects of the heads of all the metatarsal >ones, and connecting them together, is the deep transverse ligament if foot. It is adherent deeply to the capsular ligaments of the metaarso-phalangeal joints. Opposite a metatarso-phalangeal joint its uperficial aspect has a cartilage-lined groove in which the flexor endons are lodged. The disposition of the deep transverse ligament )f foot is very similar to that of the deep transverse ligament of palm, )ut the latter links together the four inner metacarpal bones only, and loes not include that of the thumb.

The Tarsal and Tarso-metatarsal Synovial Cavities. —These are lsually six in number (Fig. 402): (1) Posterior talo-calcaneal; (2) talo'alcaneo-navicular; (3) calcaneo-cuboid; (4) a large complicated joint

avity common to the cuneo-navicular joints, the joints between the ndividual cuneiform bones, the cuneo-cuboid joint, and the middle

arso-metatarsal joint; (5) medial tarso-metatarsal; (6) lateral tarsometatarsal or cuboideo-metatarsal. Occasionally the middle tarso-metatarsal or the cubo-cuneiform joint cavities ire independent, in which case there may be seven or even eight synovial cavities.


The Metatarso-phalangeal Joints.

The articular surfaces are the narrow convex articular surfaces of the heads of the metatarsal bones, which are prolonged more extensively on to the plantar aspect of the bone than on to the dorsal, ind the ovoid shallow cups at the proximal ends of the phalanges.


672


A MANUAL OF ANATOMY


Each joint is provided with three ligaments—a capsular, and tv collateral. The capsular ligament is continuous on its plantar surfa( with the deep transverse ligament of foot. On its deep aspect is a li of fibro-cartilage which projects into the joint, and deepens the sock( of reception for the head of the metatarsal bone. The collateral ligt ments are thick resistant bands. The dorsal part of the capsule ligament is exceedingly thin and weak; it is closely adherent to tt extensor tendon.

The metatarso-phalangeal joint of the great toe is peculiar in the there are two sesamoid bones embedded in the plantar ligament i the situations where the short muscles of the great toe are adherer to it.

The movements are chiefly those of flexion and extension.

Collateral movements, owing to the very narrow articular surfaces on tl heads of the metatarsal bones, are very limited. In the metacarpo-phalange; joints, where the articular surfaces on the heads of the metacarpal bones ai broader, collateral movements are much less restricted.


The Interphalangeal Joints.

These joints are like the metatarso-phalangeal joints, and ar provided with similar ligaments. The plantar ligament is a thic fibrocartilaginous plate which is grooved superficially for the flexc tendons, and has a deep lip projecting into the joint and deepening th socket of reception for the rounded head of the more proximal phalam

The movements are those of flexion and extension. These move ments are limited, and in some of the joints voluntary extension movt ments are impossible.

THE ARCHES OF THE FOOT.

The bones of the foot are so disposed that, as a whole, they are built togethc in the form of two arches, a longitudinal and a transverse.

The longitudinal arch is most obvious when the foot is viewed from the inne side (Fig. 397). From this point of view the talus is at the summit of the arcl the calcaneum provides a short, more vertical, posterior pillar, while a Ion anterior pillar is formed by the navicular, medial cuneiform, and the met£ tarsal bone of the great toe, which together slope obliquely downwards an forwards. The arch gradually flattens out towards the outer side of the foo' and from this point of view (Fig. 398) the cuboid is at the summit of the arc! the posterior pillar is again the os calcis, which, however, passes backwards wit only a slight inclination downwards; the anterior pillar is the fifth metatarsa the proximal end of which is only at a slightly higher level than the distal.

When the distal end of the tarsus and the proximal end of the metatarsi] are viewed from below, they are seen to be concave from side to side. Thi concavity, or transverse arch of the foot, is due to the wedge-shaped form of th component bones, and is deepest towards the inner side. It is important t notice that the transverse arch involves bones which are also concerned i: forming the anterior pillar of the longitudinal arch.

The posterior pillar of the longitudinal arch is formed by one bone, th calcaneum. The anterior pillar presents the greatest contrast to the posterior Nearly all the tarsal bones and all the metatarsals take a share in its formation It splays out from the summit of the arch to the distal end of the metatarsus Further, it is arched from side to side, and flattens out towards the outer side of the foot. The posterior pillar may be defined as the shorter, more vertical, nd rigid pillar; the anterior as the longer, more oblique, and highly elastic illar.

The arches render the foot a very elastic basis of support and a highly efficient rgan of progression. In the standing position the larger component of the ody weight, transmitted from the tibia to the talus, passes through the calaneus to the heel; the smaller component through the longer anterior pillar d the ball of the foot, which corresponds in position to the distal end of the letatarsus. The superincumbent weight, which chiefly impinges on the inner ide of the foot, tends to flatten the arches and to thrust the head of the astragalus ownwards between the upper ends of the two pillars of the longitudinal arch, 'he plantar calcaneo-navicular ligament keeps the upper ends of the two pillars a approximation, and supports the head of the talus from below. In this respect


Fig. 403. —Sagittal Section of Ankle and Foot passing through the Great Toe.

1, plantar calcaneo-navicular ligament; 2, inner sesamoid bone.

the plantar calcaneo-navicular ligament is the most important ligament in the oot. The longitudinal arch is also maintained by the tendons of the long lexor muscles, which pass into the sole from behind the medial malleolus, the Tbialis posterior being the most important (p. 622); by the flexor digitorum brevis; by the long plantar ligament; and by the plantar aponeurosis (p. 642), vhich plays the part of a string to a bow, and prevents undue separation of

he lower ends of the two pillars. In walking, the heel is first raised from the ground by the powerful calf muscles, the posterior pillar playing the part of an irm of a lever. Being rigid and composed of one bone, the calcaneum, there is 10 loss of effective power, as would ensue if the posterior pillar had movable components. The weight of the body is then gradually thrown forwards through the anterior pillar on to the toes. As this pillar is elastic and slight gliding lisplacements take place between its component parts, this movement is effected smoothly and evenly.