69 



ventral ang-le of the ischial symphysis and the acetabulum ; 

 and a posterior one from the ischial symphysis. The anterior 

 head passes through a slit in the adductor magnus and unites 

 with the posterior head in the distal third of tlie thig-h. The 

 tendon of insertion is long- and thin and joins that of the rectus 

 internus minor to be inserted into the tibia just below its head. 



The Adductor Brevis is a short wide muscle lying beneath 

 the upper end of the adductor magnus. It arises from the pubic 

 and ischial symphyses and is inserted into the proximal half 

 of the femur. 



The Pectineus is a smaller muscle lying along the outer (or 

 extensor) side of the adductor brevis. It arises from the anter- 

 ior half of the pubic symphysis in front of the adductor brevis 

 and is inserted like it into the proximal half of the femur. 



266. Dorsal Aspect of the Deep Muscles of the 

 Thigh. The Ilio-psoas arises by a wide origin from the inner 

 surface of the acetabular portion of the ilium ; it turns around 

 the anterior border of the ilium and crosses in front of the hip 

 joint, where for a short part of its course it is superficial be- 

 tween the heads of the vastus internus and of the rectus anticus 

 femoris ; it then passes down the thigh beneath these muscles 

 and is inserted into the back of the proximal half of the femur. 



The Quadratus Femoris is a small muscle on the back of the 

 upper part of the thigh ; it arises from the ilium above the 

 acetabulum and from the base of the iliac crest ; it lies beneath 

 the pyriformis and is inserted into the inner surface of the prox- 

 imal third of the femur, between the pyriformis and the ilio-psoas. 



The Obturator is a deeply located muscle which arises from 

 the whole length of the iliac symphysis and the adjacent parts 

 of the iliac and pubic symphyses and is inserted into the head 

 of the femur close to the gluteus. 



267. Muscles of the Tibial Portion of the Leg. 

 The Gastrocnemius is the large muscle forming the calf of the 

 leg ; it has two heads of origin, the larger of which arises by 

 a strong flattened tendon from the flexor surface of the distal 

 end of the femur ; while the smaller head which joins the 

 main muscle about one-fourth of its length below the knee, 

 arises from the edge of the triceps extensor femoris where it 

 covers the knee. The muscle is thickest in its upper third and 

 tapering posteriorly ends in the strong Tendon of Achilles, 



