SUPERFICIAL GROUP OF MUSCLES. 



189 



muscles, gastrocnemius, soleus, and plantaris, which extend the 



ankle. The first two are large, giving rise to the prominence 



on the surface, and end below by a 



common tendon ; but the last is 



inconsiderable in size, and chiefly 



tendinous. 



The GASTROCNEMIUS (fig.' 71, A), 



the most superficial muscle, has two 

 distinct pieces or heads, which arise 

 From the lower end of the femur 

 (fig. 61, p. 158). The inner head of 

 origin is attached by a large tendon 

 to an impression at the upper aspect 

 of the inner condyle, behind the 

 insertion of the adductor magnus ; 

 and by short tendinous fibres to the 

 line above the condyle. The outer 

 Imnl is attached by tendon to a pit 

 on the outer surface of the corre- 

 sponding condyle, above the attach- 

 ment of the popliteus muscle, and 

 to the posterior surface of the bone 

 immediately above the condyle. The 

 fleshy fibres of the two heads are 

 united along the middle line by a 

 narrow thin aponeurosis, and termi- 

 nate below with the soleus in the 

 common tendon of insertion. 



One surface is covered by the 

 tascia. The other is in contact with 

 the soleus and plantaris, and with 

 the popliteal vessels and the internal 

 popliteal nerve. The heads, by which 

 the muscle arises, assist to form the 

 lateral boundaries of the popliteal 

 space, and are crossed by the tendons 

 of the hamstrings. The inner head 

 is larger, and descends lower than the 



FIG. 72. SECOXD VIEW OF THE BACK OF THE LEG (ILLUSTRATIONS 

 OF DISSECTIONS). 



relations ; 



Muscles : 



A. (rastrocnemius, cut. 



B. Soleus. 



c. Plantaris. 



D. Serairuembranosus. 



E. Semitendinosus. 



F. Tendo Achillis. 



Vessels: 

 a. Popliteal artery. 



b. Internal lower articular. 



c. External lower articular. 



d. Internal saphenous vein. 



e. External saphenous vein. 



Xcrves : 



1. External popliteal. 



2. Internal popliteal. 



3. Short saphenous, cut. 



