DISTRIBUTION OF CLTAXEOi'S B RANCHES 825 



twelftli dorsal and the ilio-hypogastric nerves; the middle ui)[)er area receives the 

 external divisions of the j)osterior primary Ijranehes of the U))})er three lumliar 

 nerves, and the inner and ujjiier area is suijjdied Ijy twigs fr(jm the external divi- 

 sions of the posterior primary branches of the upper two or three sacral nerves 

 (fig. 469b). 



Of the lower three areas the outer receives filaments from the second and third 

 lund)ar nerves through the external cutaneous branch of the lumbar plexus, the 

 middle area is supplied l»y the first, second, and third sacral nerves through the 

 small sciatic nerve, and the inner area by the second and third sacral nerves through 

 the perforating cutaneous l)ranch of the sacral plexus (fig. 469b). 



On the back of the thigh there are three areas. The external and the internal 

 are su})pHed l)y the second and third lumbar nerves, the former thvougli the 

 external cutaneous branch of the lumbar plexus and the latter through the internal 

 cutaneous branch of the anterior crural nerve; the middle area receives twigs from 

 the first, second, and third sacral nerves through the small sciatic branch of the 

 sacral plexus (fig. 469b). 



The front of the thigh is supplied by the first, second, and third lumbar nerves, 

 and there are five cutaneous areas; the outer receives twigs of the second and third 

 lumbar nerves through the external cutaneous nen'e. There are two mesial areas, 

 an upper and a lower. The former is suj^plied by the crural l^ranch of the genito- 

 crural wliich conveys twigs of the first and second lumbar nerves, and the latter 

 receives filaments of the second and third luml)ar nerves through the middle 

 cutaneous branch of the anterior crural nerve. The small upper and internal area 

 is supi)lied by the first lumbar nerve through the ilio-inguinal branch of the 

 luml>ar ])lexus, and the lower internal area receives twigs of the second and third 

 lumbar nerves through the internal cutaneous branch of the anterior crural nerve 

 (fig. 469b). 



The front of the knee is supi^lied b}^ the second, third, and fourth lumbar 

 nerves through the middle cutaneous, the internal cutaneous, and the long saphen- 

 ous liranches of the anterior crural nerve (fig. 469b). 



The skin over the region of the popliteal space receives filaments internally 

 from second, third and fourth luml)ar nerves through the internal cutaneous l)ranch 

 of the anterior crural nen-e and through the superficial division of the ol:)turator 

 nerve; mesially and externally it receives twigs of the first three sacral nerves 

 through the small sciatic nerve (fig. 469b). 



The skin of the front and inner side of the leg is supplied h\ the third and 

 fourth lumbar nerves through the long saphenous branch of the anterior crural 

 nerve, and the skin of the front and outer side of the leg receives filaments of the 

 fifth luml)ar, and the first and second sacral nerves through the external cutaneous 

 branch of the external poi)liteal nerve. The skin of the lower and middle j^art of 

 the anterior aspect of the leg is supplied by tlie musculo-cutaneous nerve which 

 convevs filaments of the fourth and fifth lumliar and the first sacral nerve 

 (fig. 469b}. 



In the skin of the ])ack of the leg five areas can be distinguished, two internal, 

 upper and lower, two middle, ujjper and lower, and an external. The ui)per and 

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

 internal cutaneous branch of the anterior crural nerve and the superficial Viranch of 

 tlie obturator nerve, the lower internal area receives filaments from the third and 

 fourth lumbar nerves through the long sa]ihenous nerve. The upper middle area 

 is sujiplied by the first, second an<l third sacral through the small sciatic nerve. an<l 

 the lower middle area by the first and second sacral nerves through the external 

 saphenous nerve. The outer area is sup])lied l)y the fifth luml)ar and the first and 

 second sacral nerves through the external cutaneous branch of the external popli- 

 teal nerve (fig. 469b). , 



The skin of the dorsum of the foot is supplied principally b}' the fourth and 

 fifth lumbar and by the first sacral nerves; the majority of the nerve filaments 

 travel by the musculo-cutaneous nerve, but the adjacent sides of the first and 

 second toes are supplied by the anterior crural nerve, and the outer side of the 

 dorsum of the little toe is su])plied by the first and second sacral nerves through 

 the external saphenous nerve (fig. 469b). 



