996 



THE NERVOUS SYSTEM 



two mesial areas, an upper and a lower. The former is supplied by the lumbo-inguinal 

 (crural) branch of the geni to-femoral (geni to-crural), which conveys twigs of the 

 first and second lumbar nerves; the latter receives fibres of the second and 

 third lumbar nerves through one of the anterior (middle) cutaneous branches of 

 the femoral (anterior crural) nerve. The small upper and inner area is supplied 

 by the first lumbar nerve through the ilio-inguinal, and the lower inner area 

 receives twigs of the second and third lumbar nerves through one of the anterior 

 cutaneous branches (internal cutaneous) of the femoral (anterior crural) nerve 

 (fig. 710). 



The front of the knee is supplied by the second, third, and fourth lumbar nerves 

 through the anterior (middle and internal) cutaneous and saphenous (long saphenous) 

 branches of the femoral (fig. 710). 



Of the skin over the region of the popliteal space, the inner portion receives 

 fibres from the second, third, and fourth lumbar nerves through the anterior (inter- 

 nal) cutaneous branch of the femoral (anterior crural) nerve and through the super- 

 ficial division of the obturator nerve; the middle and lateral portion receives twigs 

 of the first three sacral nerves through the posterior cutaneous (small sciatic) nerve 

 (fig. 710). 



FIG. 713. DIAGRAM OF THE CUTANEOUS AREAS OF THE LOWER EXTREMITY. (After Head.) 



I? 'S 2 V 



L ,' 



The skin over the front and inner side of the leg is supplied by the third and 

 fourth lumbar nerves through the saphenous nerve, and the skin of the front and 

 outer side of the leg receives nerve-fibres from the fifth lumbar, and the first and 

 second sacral nerves through the sural cutaneous (fibular communicating) branch 

 of the common peroneal (external popliteal) nerve. The skin of the lower and mid- 

 dle part of the front of the leg is supplied by the superficial peroneal (musculo- 

 cutaneous) nerve which conveys filaments of the fourth 'and fifth lumbar and the 

 first sacral nerve (fig. 710). 



In the skin of the back of the leg five areas can be distinguished, two inner, 

 upper and lower, two middle, upper and lower, and an outer area. The upper 

 inner area is supplied by the second, third, and fourth lumbar nerves through an 

 anterior cutaneous branch (internal cutaneous) of the femoral (anterior crural) 

 nerve and the superficial branch of the obturator nerve. The lower inner area 

 receives filaments from the third and fourth lumbar nerves through the saphenous 

 nerve. The upper middle area is supplied by the first, second, and third sacral nerves 



