muscle. The vastus intermedius envelops the femur, and is concealed by the other muscles. The rectus M. Rectus Femoris. femoris has a double tendinous origin. (1) The straight head arises from the inferior anterior spine of the ilium (Fig. 366, p. 412); (2) the reflected head springs from a rough groove on the dorsum ilii just above the highest part of the acetabulum (Fig. 366, p. 412). A bursa lies beneath this head of origin. The two heads, bound together and connected to the capsule of the hip-joint by a band of fascia derived from the deep surface of the tensor fascia latæ (ilio-tibial tract), give rise to a single tendon which extends, for some distance, on the anterior surface of the muscle, and from which the muscular fibres arise. The muscular fibres springing from this tendon, and also from a median septal tendon, present a bipennate arrangement, and end below in a broad tendon which passes proximally, for some distance, along the posterior surface of the muscle. This tendon gradually narrows towards the knee, and spreading out again, is inserted into the proximal border of the minimus (insertion) Vastus medialis. (origin) Vastus medius AN patella. It receives laterally and medially FIG. 361.-MUSCLE-ATTACHMENTS TO THE parts of the insertions of the lateral and medial vasti muscles, and on its deep surface is joined by the insertion of the vastus intermedius. A bursa, which communicates with the synovial membrane of the knee-joint, lies between the tendon and the front of the distal end of the shaft of the femur. FIG. 362.-TRANSVERSE SECTION OF THE THIGH (HUNTER'S ADDUCTOR CANAL). M. Vastus Lateralis.-The vastus lateralis has an origin, partly fleshy, partly membranous, from (1) the capsule of the hip-joint, (2) the tubercle of the femur, (3) a concave area on the anterior surface of the shaft of the bone medial to the greater trochanter, (4) the distal border of the greater trochanter, (5) the lateral margin of the gluteal tuberosity of the femur and the tendon of the gluteus maximus, (6) the proximal half of the linea aspera, and (7) the fascia lata and lateral intermuscular septum (Fig. 360, p. 406). It forms a thick, broad muscle directed distally and forwards, and is inserted by a broad membranous tendon into (1) the lateral border of the tendon of the rectus femoris, (2) the proximal and lateral border of the patella, and (3) the capsule of the knee-joint and the fibular collateral ligament of the patella. A bursa intervenes between it and the membranous insertion of the gluteus maximus. M. Vastus Medialis.-The vastus medialis is larger than the vastus lateralis and has a more extensive origin, from (1) the distal two-thirds or more of the spiral line, the linea aspera, and the proximal two-thirds of the line leading from the linea aspera to the medial condyle of the femur; (2) the membranous expansion of the fascia lata which lies beneath the sartorius and forms the roof of the adductor canal; and (3) the medial intermuscular septum and the tendon of the adductor magnus (Figs. 359, p. 404, and 365, p. 410). RTORIUS Semi-membranosus Popliteus (insertion) From its origin the muscle is directed distally and laterally towards lateral ligament of the knee the knee; it is inserted by a strong Attachment of tibial col Gracilis (insertion) aponeurotic tendon into (1) the medial border of the rectus tendon; (2) into the proximal and medial border of Semi-tendinosus (insertion) the patella; and (3) the capsule of the knee-joint and the collateral ligament of the patella. The muscle conceals the medial side of the body of the femur and the vastus intermedius, with which it is closely incorporated in its distal two-thirds. FIG. 363.—MUSCLE-ATTACHMENTS TO THE MEDIAL SIDE Surfaces-but not the medial surface: OF THE PROXIMAL PART OF THE RIGHT TIBIA. (2) the distal half of the lateral lip of the linea aspera and the proximal part of the line leading therefrom to the lateral condyle; and (3) a corresponding portion of the lateral intermuscular septum (Fig. 359, p. 404). It is For the most part deeply placed, the muscle is directed distally to an insertion into the deep surface of the tendons of the rectus and vasti muscles by means of fibres which join a membranous expansion on its surface. closely adherent to the vastus lateralis muscle in the middle third of the thigh; it is inseparable from the vastus medialis below the proximal third. In the distal third of the thigh it conceals the articularis genu muscle, a bursa, and the proximal prolongation of the synovial membrane of the knee-joint. M. Articularis Genu. The articularis genu (O.T. subcrureus) muscle consists of a number of separate bundles of muscular fibres arising deep to the vastus intermedius from the distal fourth of the anterior surface of the femur, and inserted into the synovial membrane of the knee-joint. The four elements composing the quadriceps femoris muscle have been traced in their convergence to the patella. Their ultimate insertion is into the tubercle of the tibia (Fig. 363), by means of the ligamentum patellæ, and the vasti muscles are in addition connected with the collateral ligaments of the patella. The patella, indeed, is in one sense a sesamoid bone formed in the tendon of the muscle, the ligamentum patella being the real tendon of insertion, and the collateral ligaments fascial expansions from its borders. The insertion of the muscle forms the anterior part of the capsule of the knee-joint. FIG. 364. THE VESSELS AND NERVES ON THE POSTERIOR ABDOMINAL WALL. Nerve-Supply. The parts of the quadriceps extensor are supplied by separate branches of the femoral nerve (L. 3. 4.). Actions.-The quadriceps muscle is the great extensor of the leg at the knee-joint. The articularis genu draws proximally the synovial sheath of the joint during this movement. The rectus femoris is in addition a flexor of the hip-joint. The straight head acts when the movement begins; the reflected head is tightened when the thigh becomes bent. The ilio-psoas muscle is a compound muscle, consisting of two elements,psoas (major and minor), connecting the femur and pelvic girdle to the axial skeleton; and another element, the iliacus, extending between the hip bone and the femur. The muscles chiefly occupy the posterior wall of the abdomen and pelvis major, only their lower parts appear in the thigh below the inguinal ligament, in the lateral part of the femoral triangle. M. Psoas Major.-The psoas major is a large piriform muscle, which has an extensive origin, by fleshy fibres, from the vertebral column in the lumbar region. It arises from (1) the intervertebral fibro-cartilages above each lumbar vertebra, and the adjacent margins of the vertebræ from the inferior border of the 12th thoracic to the superior border of the 5th lumbar vertebra; (2) it arises also from four aponeurotic arches which pass over the sides of the bodies of the first four lumbar vertebræ; and (3) it has an additional origin posteriorly from the Piriformis Gluteus medius Gluteus maximus (insertion) Adductor magnus (insertion) Adductor brevis (insertion) transverse processes of all the lumbar vertebræ. The fibres form a fusiform muscle which projects over the superior aperture of the pelvis and passes behind the inguinal ligament, to end in a tendon which is inserted into the apex of the lesser trochanter of Obturator internus and the femur (Fig. 365). A bursa, gemelli (insertion) Obturator externus (insertion) Quadratus femoris Ilio-psoas (insertion) Pectineus (insertion) -Vastus medialis (origin) FIG. 365.-MUSCLE-ATTACHMENTS TO THE POSTERIOR ASPECT which may be continuous with the synovial cavity of the hipjoint, separates the tendon from the pubis and the capsule of the hip-joint. M. Psoas Minor.-The psoas minor (O.T. parvus) is often absent (40 per cent). It arises from the intervertebral fibro-cartilage between the last thoracic and first lumbar vertebræ, and from the contiguous margins of those vertebræ. The muscle is closely apposed to the anterior surface of the psoas major. It forms a slender fleshy belly, and is inserted, by a narrow tendon, into the middle of the linea terminalis and the ilio-pectineal eminence, its margins blending with the fascia covering the psoas major. M. Iliacus. The iliacus muscle arises in the pelvis major by fleshy fibres, mainly from a horseshoe-shaped origin around the margin of the iliac fossa; it has additional origins also from the ala of the sacrum, the anterior sacro-iliac, lumbo-sacral, and ilio-lumbar ligaments, and outside the pelvis, from the proximal part of the capsule of the hip-joint (ilio-femoral ligament). It is a fan-shaped muscle, and its fibres pass distally over the hip-joint towards the lesser trochanter of the femur. Lying lateral to the psoas muscle, it passes through the femoral triangle, and is inserted by fleshy fibres (1) into the lateral side of the tendon of the psoas major; (2) into the concave anterior and upper surfaces of the lesser trochanter; and (3) into the body of the femur distal to the lesser trochanter for about an inch (Fig. 365); and (4) by its most lateral fibres into the capsule of the hip-joint. These fibres are often separate, forming the iliacus minor, or iliocapsularis. Nerve-Supply. The psoas major is supplied directly by branches from the anterior rami of the second and third lumbar nerves with additional branches in some cases from the first and fourth. The psoas minor receives a nerve from the first or second lumbar nerve. The iliacus is supplied by branches from the femoral nerve (L. 2. 3. 4.) within the abdomen. Actions. The psoas minor assists the psoas major in flexing forwards and laterally the vertebral column. Besides this action the psoas major acts with the iliacus muscle as a flexor of the hip-joint. With the thighs fixed the two muscles can draw the trunk downwards. M. Pectineus. The pectineus muscle arises by fleshy fibres from, (1) the sharp anterior portion of the linea terminalis of the pubis, and the triangular surface of the pubic bone in front of the linea terminalis (Fig. 366, p. 412), (2) the femoral surface of the ligamentum lacunare, and (3) the pectineal portion of the fascia lata which covers it. Forming a broad muscular band, which lies in the floor of the femoral triangle, medial to the ilio-psoas, it is inserted by a thin flat tendon, about two inches in length, into the proximal half of the pectineal line, leading from the back of the lesser trochanter of the femur towards the linea aspera; its distal attachment being placed in front of the insertion of the adductor brevis muscle (Fig. 365, p. 410). The muscle may be occasionally divided into medial and lateral parts, the former innervated by the obturator, the latter by the femoral nerve. Nerve-Supply. The pectineus is always supplied by a branch of the femoral nerve (L. 2. 3.) which passes medially behind the femoral vessels to enter its lateral border. It receives in some instances an additional nerve from the obturator, or when that is present, the accessory obturator nerve. Actions. The muscle is mainly an adductor of the hip-joint. It is also a flexor of the hip. THE MUSCLES ON THE MEDIAL SIDE OF THE THIGH. The muscles on the medial side of the thigh include the adductors of the femur -the adductor longus, adductor brevis, and adductor magnus; the gracilis, and the obturator externus. The gracilis is superficially placed along the medial side of the thigh. The adductor muscles are placed in the medial part of the thigh between the hip bone and the femur, and in different vertical planes. The adductor longus is in the same plane as the pectineus and lies superficially in the femoral triangle; the adductor brevis, on a more posterior plane, is in contact with the obturator externus, and along with it is largely concealed by the pectineus and adductor longus; the adductor magnus, the largest and most posterior of these muscles, is in contact with the other adductors and the sartorius anteriorly, while its posterior surface is in relation to the hamstring muscles on the back of the thigh. M. Gracilis.-The gracilis muscle is a long flat band placed on the medial side of the thigh and knee. It arises by a tendon from the lower half of the edge of the symphysis pubis, and for a similar distance along the border of the pubic arch (Fig. 366, p. 412). Its flattened belly passes distally, on the medial side of the thigh to the knee, to end in a tendon, placed between the sartorius and semitendinosus, which expands to be inserted into the medial surface of the body of the tibia just distal to the medial condyle, behind the sartorius, and proximal to and in front of the semitendinosus (Fig. 376, p. 420). It is separated from the sartorius tendon by a bursa, and deep to its tendon is another bursa, common to it and the semitendinosus. It is superficial in its whole extent. Nerve-Supply.-Obturator nerve (L. 2. 3.). Actions. The gracilis has a threefold action. It adducts the thigh, and it flexes and rotates medially the tibia. M. Adductor Longus.-The adductor longus is a triangular muscle which lies in the floor of the femoral triangle and the floor of adductor canal (Hunter's). It arises from the anterior surface of the body of the pubis in the angle between the crest and symphysis (Fig. 366, p. 412). It extends distally and laterally, it is inserted into the middle two-fourths of the medial lip of the linea aspera in front of the adductor magnus. |