764 



MUSCLES OF THE LEG. 



[Fie. 252. 



The peroneus tertius (Fig. 251) forms a portion of the 

 extensor longus, and goes to the base of the metatarsal 

 bone of the little toe. Function. To flex the foot. 



MUSCLES ON THE BACK OF THE LEG. 



Dissection. Make an incision down the middle back part 

 of the leg from the knee to the heel, cross this at its centre 

 by a transverse incision, then turn off the integument and 

 fascia, when the muscles will be exposed. 



Gastrocnemius ya<^ P , the belly; xvqw, 

 the leg (Fig. 252) arises by two heads ; 

 one tendinous and fleshy, from the ex- 

 ternal condyle and ridge leading to it; 

 the other head has a like origin from 

 the internal condyle and its ridge. The 

 two heads have the popliteal vessels pass- 

 ing between them. They unite a little 

 below the knee and about the middle of 

 the leg form a broad flat tendon to unite 

 with the soleus or gastrocnemius internus, 

 which arises fleshy from the head and 

 upper third of the fibula, from the up- 

 per posterior surface of the tibia, below 

 the popliteus, and from the internal an- 

 gle of the tibia for four or five inches. 

 A large fleshy belly is formed, constitu- 

 ting the calf of the leg, which ends in 

 a tendon to unite with that of the gas- 

 trocnemius externus. The union of the 

 two forms the tendo-Achillis , which goes 

 to be inserted into the posterior part of 

 the os calcis. A bursa is found between 

 this tendon and the bone. Function. To extend the foot. 



FIG. 252 represents the Superficial Muscles on the back of the Leg. a Ten- 

 don of the biceps, b Tendons of the inner hamstring muscles, c Popliteal 

 space, d Gastrocnemius. e Soleus. / Tendo-Achillis. g Its insertion into 

 the calcis. h Peroneus longus and brevis tendons, i Tendons of the fiexor- 

 longus-digitorum, and tibialis posticus. 



