THE POSTERIOR TIBIOFIBULAR REGION 233 



the fifth metatarsal, sending a small slip to the outer e<l#e 

 of the extensor of the little toe or forepart of the metatarsal 

 bone. 



Nerves. Musculocutaneous branch of the external popliteal 

 or peroneal nerve. 



The Posterior Tibiofibular Region (Flexors) 



Superficial Muscles. 1. Mm. Gastrocnemius and Soleus (m. 

 triceps surse). Gastrocnemius has two large heads from the 

 femur, terminating at the middle of the leg in a common tendon. 

 Outer head from the depression on the outer side of the external 

 condyle above the tuberosity, and from the posterior surface 

 of the femur just above that condyle. Inner head from the 

 upper part of the internal condyle behind the adductor tubercle, 

 and lower end of the supracondylar ridge. The two heads 

 enlarge, and soon meet, do not join, separated superficially 

 by a groove and deeply by a thin band. 



The inferior tendon is broad and aponeurotic, and on the 

 deep surface. 



The lower edge of each muscular part is convex downward; 

 the inner head is the broader and thicker, and descends the 

 lower in its insertion into the common tendon. A bursa is 

 between it and the semimembranosus, and another between 

 it and the femur. 



Outer head may develop a sesamoid fibrocartilage or bone 

 over the condyle of the femur. 



Soleus. Origin, externally from the posterior surface of 

 the head and upper third of the shaft of the fibula; internally, 

 oblique line and inner border of the tibia to its middle, and 

 from a tendinous arch over the popliteal vessels and nerve; 

 fibers rise to a large extent from two tendinous laminae which 

 descend in the muscle, one from the fibula and one from the 

 tibia. Fibers from the anterior surfaces of these laminae con- 

 verge to a median septum; fibers from their posterior surfaces 

 pass down and back to an aponeurosis covering the back surface 

 of the muscle. The tendon of insertion is prolonged from this 

 aponeurosis, joined by the median septum. Muscular fibers 

 are continued down on the deep surface of the tendo Achillis 

 near to the heel. The tibial head is almost peculiar to man. 



