THE POSTERIOR LIMB , 279 



(d) The tensor fasciae cruris. Origin: By a long slender 

 tendon, from the transverse process of the fourth sacral 

 vertebra. Insertion : Lateral fascia of the leg. This slender 

 muscular slip underlies the biceps femoris. 



(e) The semimembranosus. Origin in two portions. First 

 (superficial) portion: Fascia covering the first head of the 

 biceps. Second (deep) portion: Lateral process of the 

 ischial tuberosity. Insertion : In common with the gracilis 

 on the fascia of the proximal portion of the medial surface 

 of the leg. This fascia is contracted into two ligaments, 

 one of which carries the insertion of the muscle to the distal 

 end of the tibial tuberosity, the other to the distal end of 

 the leg, where it joins the tendon of the heel (tendo cal- 

 caneus). 



(/) The semitendinosus. Origin: Ischial tuberosity. In- 

 sertion: Medial condyle of the tibia. The muscle is com- 

 pletely enclosed by the adductor magnus, which must be 

 split to expose it. 



Blood-Vessels and Nerves of the Thigh 



The femoral artery (a. femoralis) traverses the medial surface 

 of the thigh, beginning at the dorsal side of the inguinal ligament, 

 where it continues the external iliac artery. Immediately distal to 

 the inguinal ligament it gives off posteriorly the deep artery of the 

 thigh (a. profunda femoris). The latter passes to the dorsal side of 

 the pectineus and adductor brevis muscles and is distributed to the 

 posterior proximal portion of the limb, chiefly to the adductores 

 longus and magnus. A second branch, the lateral circumflex artery 

 (a. circumflexa femoris lateralis), is given off from the anterolateral 

 wall. It passes between the second head of the rectus femoris and 

 vastus lateralis, on the one hand, and the two portions of the vastus 

 intermedins, on the other. It supplies various parts of the quadri- 

 ceps femoris group. A third branch of the femoral, the superficial 

 epigastric artery (a. epigastrica superficialis), given off medially, 

 and passing to the abdominal wall, has been divided (p. 221). At 

 the beginning of the distal third of the thigh, a small branch, the 

 a. genu suprema, passes over the medial condyle of the femur to 



