514 THE MUSCLES AND FASCIAE 



the ligamentum patellae, which is continued from the lower part of the patella to the tuberosity 

 of the tibia, as the proper tendon of insertion of the muscle. A synovial bursa, the deep patellar 

 bursa (bursa infrapatellaris prof undo), is interposed between the tendon and the upper part 

 of the tuberosity of the tibia; and another, the prepatellar bursa (bursa pracpatellaris siib- 

 cutanea), is placed over the patella itself. This latter bursa often becomes enlarged, constituting 

 "housemaid's knee." 



The Subcrureus (m. articularis genu) is a small muscle, usually distinct from 

 the Crureus, but occasionally blended with it, which arises from the anterior 

 surface of the lower part of the shaft of the femur, and is inserted into the upper 

 part of the cul-de-sac of the capsular ligament, which projects upward beneath 

 the Quadriceps for a variable distance. It sometimes consists of several separate 

 muscle bundles. 



Nerves. The Tensor fasciae femoris is supplied by the fourth and fifth lumbar and first 

 sacral nerves through the superior gluteal nerve; the other muscles of this region, by the second, 

 third, and fourth lumbar nerves, through branches of the femoral. 



Actions. The Tensor fasciae femoris is a tensor of the fascia lata; continuing its action, the 

 oblique direction of its fibres enables it to abduct and to rotate the thigh inward. In the erect 

 posture, acting from below, it will serve to steady the pelvis upon the head of the femur, and by 

 means of the iliotibial band it steadies the condyles of the femur on the articular surfaces of the 

 tibia, and assists the Gluteus maxim us in supporting the knee in the extended position. The Sar- 

 torius flexes the leg upon the thigh, and, continuing to act, flexes the thigh upon the pelvis; it next 

 rotates the thigh outward. It was formerly supposed to adduct the thigh, so as to cross one 

 leg over the other, and hence received its name of Sartorius, or tailor's muscle, because it was 

 supposed to assist in crossing the legs in the squatting position. When the knee is bent the 

 Sartorius assists the Semitendinosus, Semimembranosus, and Popliteus in rotating the tibia 

 inward. Taking its fixed point from the leg, it flexes the pelvis upon the thigh, and, if one 

 muscle acts, assists in rotating the pelvis. The Quadriceps extensor extends the leg upon the 

 thigh. The Rectus muscle assists the Psoas and Iliacus in supporting the pelvis and trunk 

 upon the femur. It also assists in flexing the thigh on the pelvis, or if the thigh is fixed it will 

 flex the pelvis. The Vastus internus draws the patella inward as well as upward. 



Applied Anatomy. A few fibres of the Rectus femoris muscle are liable to be ruptured from 

 severe strain. This accident is especially liable to occur during the games of football and base- 

 ball. The patient experiences a sudden pain in the part, as if he had been struck, and the 

 Rectus muscle stands out and is felt to be tense and rigid. The accident is often followed by 

 considerable swelling from inflammatory effusion. Occasionally the Quadriceps extensor may 

 be torn away from its insertion into the patella, or the tendon of the Quadriceps may be rup- 

 tured about an inch above the bone. This accident is caused in the same manner that fracture 

 of the patella by muscular action is produced viz., by a violent muscular effort to prevent 

 falling while the knee is in a position of semiflexion. A distinct gap can be felt above the 

 patella, and, owing to the retraction of the muscle fibres, union may fail to take place. Sudden 

 and powerful contraction of the Quadriceps extensor femoris is the usual cause of transverse 

 fracture of the patella. 



2. The Internal Femoral Region. 



Gracilis. Adductor longus. 



Pectineus. Adductor brevis. 



Adductor magnus. 



Dissection. These muscles are at once exposed by removing the fascia from the fore part 

 and inner side of the thigh. The limb should be abducted, so as to render the muscles tense and 

 easier of dissection. 



The Gracilis (m. gracilis} (Figs. 381 and 387) is the most superficial muscle 

 on the inner side of the thigh. It is thin and flattened, broad above, narrowing 

 and tapering below. It arises by a thin aponeurosis from the lower half of the 

 margin of the symphysis and the anterior half of the pubic arch. The fibres pass 

 vertically downward, and terminate in a rounded tendon which passes behind the 

 internal condvle of the femur, and, curving around the inner tuberositv of the tibia. 



