Tendon of AcJiilles 



487 



The g-as f rocnemiiis arises from the condyles of the femur, and 

 spreads out into two bellies, of which the inner is the larger ; it is 

 inserted with the subjacent soleus into the tendo Achillis. The short 

 saphenous vein courses up between the bellies, separated from them 

 by the deep fascia. (For bursce, see p. 478.) 



The soleus arises from the back of the head and the upper part of 

 the fibula, and from a tendinous arch over the ending of the popliteal 

 artery which carries it to the oblique line of the tibia, along which 

 it also arises, and down the middle third of the posterior border of 

 the tibia. The muscle lies beneath the gastrocnemius (the opposed 

 surfaces being aponeurotic) and joins with it in the formation of the 

 tendo Acnillis. This tendon is inserted into the lower part of the 

 posterior surface of the os calcis, a bursa intervening between it and 

 the upper part of that surface. It is most slender at about an inch 

 above the heel. The soleus covers the deep layer of muscles, the 

 posterior tibial vessels and nerve, and the peroneal vessels, all of 

 which are separated from the soleus by the second layer of deep 

 fascia. 



The gastrocnemius flexes the knee, and, acting with the soleus, 

 extends the foot. The two muscles are supplied by the sural branches 

 of the internal popliteal nerve. 



Achilies-tt- notomy. The tendon may require section in talipes 

 equinus, in fracture of the tibia when there is difficulty in adjusting 

 the fractured surfaces, or in keep- 

 ing them in apposition, and after 

 subcutaneous osteotomy of a 

 bowed leg. For the operation, 

 the foot is flexed, so as to tighten 

 the tendon, and the slender knife 

 is introduced beneath its deep 

 surface. If the knife be directed 

 from the skin-surface of the ten- 

 don, there is a risk of dividing 

 the posterior tibial artery, and 

 especially so when the operation 

 is being done for talipes, as in 

 that case the tendon lies very 

 close behind the artery. 



Rupture of the tendon may 

 occur with a sudden and painful 

 snap from muscular action, the 

 patient thinking that someone 

 has hit him above the heel. It 

 is treated by bending the knee 

 and extending the foot, the limb being kept in that position by a strap 

 which runs from a loop in the heel of a slipper to the back of a collar 



