THE LEG 359 



(P- 336). Now follow them proximally along the posterior 

 margin of the medial surface of the tibia to the medial side of 

 the knee, where they were displayed when the superficial part of 

 the medial region of the thigh was dissected (p. 227). The vein 

 and nerve lie close together. 



The posterior branch of the medial cutaneous nerve of the 

 thigh was also found when the medial side of the thigh was 

 dissected. In the calf it lies lateral and posterior to the saphenous 

 nerve, and should now be traced to its termination in the area 

 of the medial head of the gastrocnemius (Fig. 161). 



The terminal part of the posterior cutaneous nerve of the 

 thigh was found when the popliteal area was being dissected 

 (p. 306). It pierces the popliteal part of the deep fascia a little 

 below the middle of its length, and should now be traced as it 

 descends through the superficial fascia to the middle of the 

 calf (Fig. 161). Deep to the terminal part of the posterior 

 cutaneous nerve of the thigh, in the groove between the two 

 heads of the gastrocnemius, lie the upper part of the small 

 saphenous vein and the medial cutaneous nerve of the calf. 

 Both structures have been already partially investigated. When the 

 popliteal fossa (p. 309) was dissected the vein was found piercing 

 the popliteal fascia and ending in the popliteal vein, whilst the 

 nerve was found arising from the tibia! nerve ; and, in the 

 dissection of the dorsum of the foot (p. 336), the vein was seen 

 commencing from the lateral end of the dorsal venous arch, 

 whence it passed backwards below, and upwards behind the 

 lateral malleolus. The remaining part of the vein must now 

 be cleaned. It ascends along the lateral border of the tendo 

 calcaneus, accompanied by the sural nerve, and then in the 

 groove between the two heads of the gastrocnemius, accom- 

 panied by the medial cutaneous nerve of the calf. The sural 

 nerve was found, in a previous dissection (p. 338), lying 

 in close association with the small saphenous vein behind 

 the lateral malleolus. Trace it upwards to the point where it 

 is formed by the union of the medial cutaneous nerve of the 

 calf and the anastomotic peroneal nerve ; the union usually 

 takes place at the lateral border of the proximal part of the 

 tendo calcaneus. From the commencement of the sural nerve 

 follow the medial cutaneous nerve of the calf upwards to the 

 point where it pierces the deep fascia, about midway between 

 the knee and the ankle, then follow the peroneal anastomotic 

 nerve to the point where it pierces the deep fascia in the proximal 

 part of the calf, superficial to the lateral head of the gastro- 

 cnemius (Fig. 161). The medial calcanean nerves will be found 

 piercing the thickened portion of deep fascia called the ligamen- 

 tum laciniatum which crosses the interval between the medial 

 malleolus and the calcaneus. They are accompanied by small 

 branches of the posterior tibial artery. 



At this stage the dissector should revise the saphenous 

 veins and the cutaneous nerves which have been seen in 

 previous dissections, but which are now, for the first time, 

 displayed from beginning to end (Figs. 163, 164, 107). 



Vena Saphena Magna. The great saphenous vein com- 



