SUPERFICIAL VEINS AND NERVES. 187 



naps of skin may be raised, the outer one as far as the fibula, and 

 the other as far as the inner margin of the tibia. 



In the fat the cutaneous nerves and vessels are to be followed. Seek 

 On the inner side, close to the tibia, are the internal saphenous nervesh! 8 

 vein and nerve, together with twigs of the internal cutaneous nerve tne fat - 

 near the knee. In the centre of the leg lies the external 

 saphenous vein, with the small sciatic nerve as its companion 

 above, and the external saphenous nerve below the middle of the 

 leg. On the outer side cutaneous offsets of the external popliteal 

 nerve will be met with. 



The superficial fascia, or the fatty layer of the back of the leg, is Superficial 

 least thick over the tibia. Along the line of the superficial vessels 

 it may be separated into two layers. 



SUPERFICIAL VEINS. Two veins appear in the dissection of the TWO super- 

 back of the leg, the inner and outer saphenous. ficial veins. 



The INTERNAL, OR LONG, SAPHENOUS VEIN (fig. 72, rf, p. 189) Internal 



has already been examined in the front of the leg (p. 176), and in 

 this part it will be seen to receive various superficial tributaries and 

 deep roots from the tibia! veins. 



The EXTERNAL, OR SHORT, SAPHENOUS VEIN (fig. 71, c) has External 



already been examined 'at its origin (p. 176), and in this part it saphenous. 

 will be seen to course along the back of the leg to the ham, where 

 it ends in the popliteal vein. It receives large branches about 

 the heel, and others on the back of the leg, communicating with 

 the internal saphenous. 



Cutaneous arteries accompanv the superficial veins and nerves of Cutaneous 



, arteries. 



the leg. 



CUTANEOUS XERVES (fig. 71). The nerves in the fat of the cutaneous 

 back of the leg are prolongations of branches already met with, nerves - 

 viz., the internal and external saphenous, external popliteal, small 

 sciatic, and internal cutaneous of the thigh. 



The INTERNAL SAPHENOUS NERVE (fig. 7 1 , 7 ) has already been internal 

 examined (pp. 161 and 177), and a few additional twigs will be ^P 11 

 cleaned in this dissection. 



The EXTERNAL OR SHORT SAPHENOUS NERVE (fig. 7 1, 5 ) is External 



formed by the union of the tibial and peroneal communicating 



branches of the internal and external popliteal nerves respectively 



(pp. 129 and 130) ; the union usually taking place about the middle 



of the leg. It runs with the external saphenous vein below the ending ; 



outer ankle, and ends on the outer side of the foot and little toe 



(p. 177). In this part 'it furnishes twigs to the skin of the lower branches. 



part of the back of the leg, and large branches over the heel. 



CUTANEOUS NERVES OF THE EXTERNAL POPLITEAL. In addition Branches of 

 to the peroneal communicating (fig. 71, 4 ), the external popliteal 

 nerve gives off one or two lateral cutaneous offsets (p. 130) to the 

 outer side and fore part of the leg. 



The SMALL SCIATIC NERVE (fig. 71, 6 ) perforates the fascia at the Termination 

 lower end of the popliteal space, and reaches to about the middle 

 of the leg with the external saphenous vein : it ramifies in the 

 integuments, and joins the external saphenous nerve. 



