388 MUSCLES ON THE LEG. 



Muscles on the Back of the Leg. 



1. Gastrocnemius Extemus, seu Gemellus, 



Arises, by two distinct heads. The first head arises from the 

 Fig. 103.* upper and back part of the internal condyle 



of the OS femoris, and from that bone, a little 

 above its condyle, by two distinct tendinous 

 origins. The second head arises tendinous 

 from the upper and back part of the exter- 

 nal condyle of the os femoris. A little be- 

 low the joint, their fleshy bellies unite in a 

 middle tendon ; and, below the middle of 

 the tibia, it sends off a broad thin tendon, 

 which joins a little above the extremity of 

 the tibia with the tendon of the following. 



2. Soleus, seu Gastrocnemius Internus, 

 Arises by two origins. The first is from 

 the upper and back part of the head of the 

 fibula, continuing to receive many of its 

 fleshy fibres from the posterior part of that 

 bone for some space below its head. The 

 other origin begins from the posterior and 

 upper part of the middle of the tibia ; and 

 runs inwards along the inferior edge of the 

 popliteus towards the inner part of the tibia, 

 from which it receives fleshy fibres for some 

 way down. The flesh of this muscle, 

 covered by the tendon of the gemellus, runs down nearly as far 

 as the extremity of the tibia ; a little above which the tendons of 



* The superficial muscles on the posterior surface of the leg. 1. Biceps 

 flexor cruris muscle, forming the outer hamstring. 2. The tendons forming 

 the inner hamstring, consisting of the tendons of the semitendinosus, semi- 

 membranosus, gracilis and sartorius. 3. The popliteal space. 4. The gastroc- 

 nemius muscle. 5, 5. The soleus muscle. 6. Tendo Achillis. 7. The posterior 

 tuberosity of the os calcis. 8. The tendons of the peroneus longus and brevis 

 muscles, passing behind the outer ankle. 9. The tendons of the deep layer of 

 muscles passing into the foot behind the inner ankle. 



