THE INTERNAL FEMORAL REGION. 423 



lower part of the thigh, so as to form a single strong tendon, which is inserted into 

 the upper part of the patella, some few fibres passing over it to blend with the 

 Ligamentum patellae. More properly, the patella may be regarded as a sesamoid 

 bone, developed in the tendon of the Quadriceps ; and 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 sy no vial bursa, the post-patel- 

 lar bursa, is interposed between the tendon and the upper part of the tuberosity of 

 the tibia ; and another, the pre-patellar bursa, is placed over the patella itself. 

 This latter bursa often becomes enlarged, constituting " house-maid's knee." 



The Subcrureus is a small muscle, usually distinct from the Crureus, but occa- 

 sionally 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 muscular 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 anterior crural. 



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, ilTwilT serve to steady the 

 pelvis upon the head of the femur, and by means of the ilio-tibial band it steadies 

 the condyles of the femur on the articular surfaces of the tibia, and assists the 

 Gluteus maximus in supporting the knee in the extended position. The Sartorius 

 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 (sartor, a tailor), 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. 



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

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

 and is sometimes known as "cricket thigh. " 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 

 patella may be ruptured about an inch above the bone. This accident is caused in the same 

 manner as fracture of the patella by muscular action is produced viz. by a violent muscular 

 effort to prevent falling whilst the knee is in a position of semiflexion. A distinct gap can be 

 felt above the patella, and, owing to the retraction of the muscular fibres, union may fail to take 

 place. 



2. 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 (Figs. 253, 256) 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 



