2. THE MEDIAL FEMORAL MUSCLES

Gracilis Adductor longus Adductor magnus
Pectineus Adductor brevis

The Gracilis (figs. 643, 645, 647) is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below. It arises by a thin aponeurosis from the medial margins of the lower one-half of the body of the pubis and the upper one-half of the inferior ramus. The fibers run vertically downwards, and end in a rounded tendon, which passes across the medial condyle of the femur posterior to the tendon of the Sartorious then curves round the medial condyle of the tibia, where it becomes flattened and is inserted into the upper part of the medial surface of the shaft of the tibia, below the condyle. A few fibers from the lower part of the tendon are prolonged into the deep fascia of the leg. At its insertion the tendon is situated immediately above that of the Semitendinosus, and its upper edge is overlapped by the tendon of the Sartorius, with which it is in part blended. It is separated from the medial (tibial collateral) ligament of the knee-joint by the tibial intertendinous bursa.

Nerve-supply.-The Gracilis is supplied by the obturator nerve (L. 2. 3 and 4).

Actions.-The Gracilis flexes the leg and rotates it medially; it also adducts the thigh.

The Pectineus (fig. 643) is a flat, quadrangular muscle, situated at the front of the upper and medial part of the thigh. It arises from the pectineal line of the pubis, and to a slight extent from the surface of bone in front of it, between the iliopubic eminence (iliopectineal eminence) and pubic tubercle, and from the fascia covering the anterior surface of the muscle; the fibers pass downwards, backwards and laterally, to be inserted into the femur along a line leading from the lesser trochanter to the linea aspera.

Relations.-Its anterior surface is in relation with the fascia lata, which separates it from the femoral vessels and long saphenous vein; its posterior surface, with the capsule of the hip-joint, the Adductor brevis, Obturator externus and the anterior branch of the obturator nerve; its lateral, border, with the Psoas major and the medial circumflex femoral vessels; its medial border, with the upper or lateral margin of the Adductor longus.

The Pectineus may consist of two incompletely separated strata; the lateral or dorsal stratum, which is constant, is supplied by a branch from the femoral nerve, or in the absence of this branch by the accessory obturator nerve; the medial or ventral stratum, when present, is a derivative of the adductor group of muscles and is supplied by the obturator nerve

Nerve-supply.—-The Pectineus is supplied by the femoral nerve (L. 2 and 3); and by the accessory obturator (L. 3), when this nerve is present. Occasionally it receives a branch from the obturator nerve.

Actions. The Pectineus adducts the thigh and flexes it on the pelvis.

Figure 646
Thigh muscles adductors - Figure 646
The Adductor longus (figs. 646, 647), the most superficial of the three adductors, is a triangular muscle, lying in the same plane as the Pectineus. It arises by a flat, narrow tendon, which is attached to the front of the pubis in the angle between the crest and the symphysis. It soon expands into abroad fleshy belly which passes downwards, backwards, and laterally, and is inserted, by an. aponeurosis, into the middle one-third of the linea aspera of the femur; between the. Vastus medialis and the Adductor magnus, with both of which it is usually blended.

Relations.—Its anterior surface is in relation with the spermatic cord, the fascia lata, by which it is separated from the long saphenous vein, and near its insertion, with the femoral artery and vein and the Sartorius: its posterior surface with the Adductores brevis et magnus, the anterior branch of the obturator nerve and near its insertion with the profunda femoris vessels; its lateral border, with the Pectineus; its medial border, with the Gracilis.

Nerve-supply.-The Adductor longus is supplied by the obturator nerve (L. 2 and 3).

Actions.-The Adductor longus adducts the thigh, flexes it on the pelvis, and rotates it laterally.

Applied Anatomy. – The Adductor longus is liable to be severely strained in those who ride much on horseback, or it may be ruptured by suddenly gripping the saddle. Occasionally, especially in cavalry soldiers, the tendon of origin becomes ossified, constituting the rider’s bone.

The Adductor brevis (figs. 645, 646) is situated behind the Pectineus and Adductor longus. It is somewhat triangular in form, and arises by a. narrow origin from the outer surface of the inferior ramus of the pubis, between the Gracilis and Obturator externus. Its fibers, passing backwards, laterally, and downwards, are inserted by an aponeurosis into the femur, along the line leading from the lesser trochanter to the linea aspera, and. into the upper part of the linea aspera immediately behind the Pectineus and the upper part of the Adductor longus.

Relations.—Its anterior surface is in relation with the Pectineus, Adductor longus, arteria profunda femoris, and anterior branch of the obturator nerve; its posterior surface, with the Adductor magnus, and posterior branch of the obturator nerve; its upper border with the medial circumflex femoral artery, the Obturator externus, and conjoined tendon of the Psoas major and Iliacus; its lower or medial border, with the Gracilis and Adductor magnus. It is pierced near its insertion by the second, or first and second, perforating arteries.

Nerve-supply.-The Adductor brevis is supplied by the obturator nerve (L. 2, 3 and 4)

Actions.—The Adductor brevis adduct; the thigh, flexes it on the pelvis and rotates it laterally.

The Adductor magnus (figs. 645, 646, 647) is a large triangular muscle, situated on the medial side of the thigh. It arises from a small part of the inferior ramus of the pubis, from the ramus of the ischium, and from the lateral portion of the inferior part of the tuberosity of the ischium. Those fibers which arise from the ramus of the pubis are short, horizontal in direction, and are inserted into the medial margin of the gluteal tuberosity of the femur, medial to the Gluteus maximus; those from the ramus of the ischium are directed downwards and laterally with different degrees of obliquity, to be inserted, by means of a broad aponeurosis, into the linea aspera and the upper part of the medial supracondylar line. The medial portion of the muscle, composed principally of the fibers arising from the tuberosity of the ischium, forms a thick fleshy mass which descends almost vertically; and ends about the lower one-third of the thigh in a rounded tendon which is inserted into the adductor tubercle on the medial condyle of the femur, and is connected by a fibrous expansion to the medial supracondylar line. At the insertion of the muscle, there is a series of osseo-aponeurosic openings, formed by tendinous arches attached to the bone. The upper four openings are small, and give passage to the perforating branches of the arterea profunda femoris. The lowest is of large size, and transmits the femoral vessels to the popliteal fossa.

These uppermost fibers are sometimes described as a separate muscle-the Adductor minimus–which is situated somewhat in front of the other parts of the muscle.

Relations.-Its anterior surface is in relation with the Pectineus. Adductores brevis et longus, the femoral and profunda vessels, and the posterior branch of the obturator nerve; a bursa intervenes between the highest part of the muscle and the lesser trochanter of the femur; its posterior surface, with the sciatic nerve, the Gluteus maximus, Biceps femoris, Semitendinosus and Semimembranosus. Its superior border lies parallel with the Quadratus femoris, the transverse branch of the medial circumflex femoral artery passing between them; its medial border is in relation with the Gracilis, Sartorius and fascia lata.

Nerve-supply.—–The Adductor magnus is a composite muscle and derives its nerve-supply from two sources. The true adductor part of the muscle is supplied by the obturator nerve (L. 3 and 4); the part which takes origin from the tuberosity of the ischium is a derivative of the hamstring muscles and is supplied by the sciatic nerve (L. 4 and 5).

Figure 647
Thigh muscles, nerves, arteries, veins transverse section at the middle of the thigh - Figure 647
Actions.-The Adductor magnus adducts the thigh and rotates it late-rally; the pubic fibers flex the thigh on the pelvis, but the ischial fibers have the opposite action. The Pectineus and the adductores adduct the thigh powerfully; they are especially used in horse exercise, the sides of the saddle being grasped between the knees by the contraction of these muscles; they rotate the thigh laterally, and when the limb has been abducted, they draw it medially, carrying the thigh across that of the opposite side. In progression, they assist in drawing forwards the lower limb. If the lower limbs be fixed, these muscles, taking their fixed points below, act upon the pelvis, serving to maintain the body in the erect posture; or, if their action be continued, flex the pelvis upon the thigh.

 


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