186 



THE NERVOUS SYSTEM. 



Fiï. 



124. 



passes under the tendon of the M. extensor carpi ulnaris into the 

 palm o£ the hand and ends as the N, volaris digiti V viedialis. 



(3. The R. ulnaris lateralis 

 passes near the thumb-rudi- 

 ment, covered by the M. ab- 

 ductor pollicis, deeply into the 

 palm of the hand, and supplies 

 by bifurcating- branches the 

 adjacent sides of the second, 

 third, fourth, and fifth fin- 

 gers {R. volares) ; it also gives 

 twigs to the muscles of the 

 palm. 



[II.] The N. radialis (Figs. 

 123, 124, and 125 R) passes 

 immediately beyond its origin 

 from the N. brachialis, between 

 the humerus and the M. triceps, 



Nerves of the ventral surface of the arm. The hand 

 supinated, and the superficial layer (Flex, carpi rad. 

 and uln. , Flex. dig. commun.) has been removed. 



R N. radialis. 



u N. ulnaris. 



vc R. cutan. inf. of the N. ulnaris. 



um Bifurcation of the N. ulnaris. 



along the bone to its 

 in this course it 



outer side , 

 gives off : — 

 Rami muscular es to the separate parts of the M. triceps. 

 The Ramus cutaneus superior (Fig. 125 re) to the skin of 



the outer surface of 

 '^' '^^' the upper arm and fore- 



arm. 



The nerve then sinks 

 deeply under the origins 

 of the M. extensor carpi 

 ulnaris and the 31. ex- 

 tensor digitorum commu- 

 nis, where it bifurcates 

 after giving off some 

 small twigs : — 



y. Small muscular 

 twigs to the extensor 

 muscles of the hand and 

 fingers. 



h. The R. radialis 

 medialis (^2), the 



The N. radialis. 



ec M. extensor carpi ulnaris. 



ed M. extensor digit, coiiim. 



R N. radialis. 



Ri R. lateralis. 



i?2 R. medialis. 



re R. cutaneus superior. 



re' R. cutaneus inferior. 



