THE SPINAL NERVES. 



185 



towards the outer side of the Plica cnliti ; in this course it supplies 

 four branches : 



a. The Ramus subscapularis passes dorsally to the 31. *iib- 



ttcapi'.laris. 



/3. A Ram us pecfo- 

 ralis (Fig. 123 up), 

 - -s forwards to the 

 31. a bdoai in o-pectoralis 

 and to the skin of 

 the pectoral region (7?. 

 cnfaneits pectorals). 



y. The JV. cutaneus 

 ant H> rack ii superior s. 

 medial is (v.c) pa a 

 to the skin oi the 

 inner side of the fore- 

 arm; this and the 

 two following nerves 

 are given off near the 

 Plica cv.liii. 



Fig- 123- 



up 



uc U 



Xerres of the ventral surface of the arm. The hand prouated. 



Upper cutaneous branch of the X. radialis. 



Jxjwer cutaneous branch of the X. radiali*. 



X. tilnaris. 



R. t-ntan. sup. of the X. idnaris. 



R. cutan. inf. of the X. ulnaris. 



R. pectoraUs of the X. ulnaris. 



re' 



I ' 



uc 

 vp 



5. The 3*. cv.tanem antibracJiil Inferior #. dorsalis s. 

 cutaneu* (uc) at once supplies branches to the J/. flexor carpi radi- 

 al is *, and then runs downwards upon the muscle and bifurcates : 



[i] The E. tateralix is distributed, by two twigs, in the 31. flexor 

 carpi ulnaris and in the skin of the second finger, to which it sup- 

 plies the Eaufi iJigitale* rolari* and dorsali*. 



[2] The R. dorxali*, after giving a cutaneous twig to the second 

 finger, is distributed by numerous twigs to the skin of the dorsal 

 surface of the hand. 



The y. ulnaris then passes between the 31. flexor carpi radiali* and 

 the tendon of the 31. sterno-radialis, sinks deeply into the Plica 

 cvljiti, where it lies between the 31. flexor carpi radialis and the 

 Flexor carpi ulnaris, then between the latter and the Flexor anti- 

 bracJiii medialis on the one side and the Flexor digitorum communis on 

 the other : it supplies branches to all these muscles, and while still 

 in the forearm divides into two terminal branches : 



a. The R. ulnaris )/iedia?i* is the smaller; it runs inwards, 



1 As this muscle increases in size during the breeding season, it would be inter- 

 esting to know whether a corresponding change takes place in the nerve. 



