446 THE INFERIOR EXTREMITY 



deep to the soleus and enters the posterior compartment of the 

 leg. 



As it traverses the popliteal fossa, the tibial nerve gives off 

 (a) muscular, (b) cutaneous, and (c) articular branches. The 

 muscular branches supply both heads of the gastrocnemius, the 

 soleus, the plantaris, and the popliteus. The cutaneous branch 

 is termed the medial cutaneous nerve of the calf (ramus 

 communicans tibialis). It descends between the two heads of 

 the gastrocnemius and unites with the peroneal anastomotic 

 nerve (r. communicans fibularis) to form the nervus suralis 

 (external saphenous) (S. i and 2) (p. 473). The articular twigs, 

 three in number, supply the knee-joint. 



The Common Peroneal (Ext. Popliteal) Nerve (L. 4, 

 5, S. i, 2) passes distally and laterally in close relation to the 

 medial aspect of the biceps tendon, and leaves the popliteal 

 fossa in the interval between the tendon and the lateral head 

 of the gastrocnemius. It then descends behind the head of 

 the fibula and winds round the lateral aspect of the fibular 

 neck, piercing the origin of the peronaeus longus. In this 

 situation the nerve ends by dividing into the superficial and 

 deep peroneal nerves (musculo-cutaneous and anterior tibial) 

 (L. 4, 5, S. i). 



The common peroneal nerve gives off no muscular branches, 

 but it supplies articular twigs to the knee-joint and gives origin 

 to the lateral sural nerve (L. 4, 5, S. i), which supplies the skin 

 over the proximal part of the tibialis anterior, and the peroneal 

 anastomotic nerve, which helps to form the nervus suralis. 



The Popliteal Lymph Glands are divided 'into a superficial 

 and a deep group. The superficial lymph glands surround the 

 small saphenous vein as it pierces the deep fascia. They receive 

 aflerents from the lateral aspect of the foot and leg, and their 

 efferents open into the deep group. 



The deep lymph glands are embedded in the fat which 

 surrounds the popliteal vessels. They receive the efferents 

 of the superficial group, and, in addition, most of the numerous 

 lymph vessels from the deep tissues of the calf and the sole of 

 the foot. The remainder of the latter pass direct to the deep 

 subinguinal lymph glands (p. 400). The efferents of the deep 

 popliteal lymph glands terminate in the deep subinguinal 

 group. 



Abscesses arising in these lymph glands follow some septic 

 infection of the leg or toes. Owing to the depth at which the 



