THE POSTERIOR LIMB 285 



femoral sesamoid. Caput mediale: The main origin is 

 on the medial condyle of the femur and its sesamoid, but a 

 smaller portion of the muscle originates in part with 

 (immediately dorsal to) the caput laterale and in part by 

 a flat tendon from the lateral edge of the patella. 

 (2) The soleus: Origin: By a strong tendon from the 

 head of the fibula. 



Insertion: Through the Achilles' tendon (tendo cal- 

 caneus). The latter passes over the posterior end of the 

 tuber calcanei, and is attached to its ventral surface. The 

 tendon is covered by that of the plantaris muscle. 



The small saphenous artery and vein lie at the posterior margin of 

 the lateral head of the gastrocnemius in company with the lesser 

 saphenous nerve. 



(b) The plantaris. Origin: Lateral condyle of the femur and 

 associated sesamoid. Insertion: The tendon passes over 

 the heel to the plantar surface of the foot, and divides into 

 four parts for insertion on the second phalanges of the four 

 developed digits. Each of these parts is perforated near its 

 termination by a tendon of insertion of the flexor digitorum 

 longus. 



The two muscles should be divided. 



(c) The popliteus. Origin: Lateral condyle of the femur. 

 The tendon passes through the capsule of the knee-joint. 

 The muscle contains the tibial sesamoid. It crosses the 

 posterior surface of the tibia obliquely, and is inserted on 

 the proximal portion of its posteromedial angle. 



(d) The flexor digitorum longus. Origin: Lateral condyle of 

 the tibia and head of the fibula, extending to the posterior 

 surface of the interosseous ligament and associated portions 

 of the tibia and fibula. Insertion: The tendon passes 

 beneath the sustentaculum tali, reaching the plantar surface 

 of the foot, where it is partly covered by the plantaris ten- 

 don. It divides into four parts for insertion on the ungual 

 phalanges of the four deve^loped digits. 



The tibial nerve lies on the medial surface of the head of the plan- 

 taris and afterwards on the medial surfaces of the popliteus and flexor 

 digitorum longus. 



