THE LEG 281 



it, or with the fascia of the leg before it reaches the tendo 

 calcaneus. 



The plantaris is supplied by a branch from the tibial nerve. 



M. Soleus. This is a flat, thick, and powerful muscle 

 which arises from both bones of the leg, as well as from a 

 strong fibrous arch which is thrown across the posterior tibial 

 vessels. Its fibular origin is from the posterior surface of the 

 head and the proximal third of the posterior surface of the 

 body of the bone ; by its tibial origin it is attached to the 

 linea poplitea of the tibia distal to the popliteal surface, and 

 more distally to the medial border of the bone as far down as 

 the middle of the leg (Fig, 104, p. 285). The soleus ends 

 in a strong stout tendon which joins with the tendon of 

 the gastrocnemius to form the tendo calcaneus (Achillis). 

 Branches from the tibial nerve supply the soleus. 



Tendo Calcaneus (Achillis). This is the most powerful 

 tendon in the body. It narrows as it descends, but near the 

 heel it again expands slightly. It is inserted into the middle 

 portion of the posterior surface of the calcaneus. The fleshy 

 fibres of the soleus are continued distally on its deep 

 surface to within a short distance of the heel. A bursa 

 mucosa intervenes between the tendo calcaneus and the 

 proximal part of the posterior surface of the calcaneus. 



Dissection. Divide the soleus muscle along its line of origin from the 

 tibia and separate it from the fibrous arch over the posterior tibial vessels 

 and nerve, then turn it to the lateral side and secure the branches which 

 the muscle receives from the peroneal and posterior tibial arteries. 



The deep fascial septum which stretches across from the tibia to the 

 fibula between the superficial and deep muscles on the back of the leg may 

 now be removed. In doing this note the manner in which it becomes 

 continuous below with the ligamentum laciniatum. On no account interfere 

 with this ligament. The posterior tibial vessels and the tibial nerve, with 

 their branches, should be dissected with as little disturbance to the deep 

 muscles as possible. The muscle which lies on the fibula is the flexor hallucis 

 longus ; the muscle on the tibia is the flexor digitorum longus ; whilst the 

 third muscle between and on a deeper plane than the other two is the 

 tibialis posterior. 



Termination of the Popliteal Artery. The termination of 

 the popliteal artery lies under cover of the proximal border of 

 the soleus. It should now be cleaned, and it will be seen to 

 end at the distal margin of the popliteus muscle by dividing 

 into the anterior and posterior tibial arteries. Further, the 

 venae comites which accompany these vessels will be observed 

 to join at this point to form the large popliteal vein. 



