Chap, xv.j NERVES OF UPPER LIMB. 283 



coraco-brachialis, latiss. dorsi, extensors at back of 

 fore-arm, outer head of triceps ; 7, 8, inner head of 

 triceps ; 7, 8, 9, flexor sublimis, flexores profund., carpi 

 uln., long, poll., pronator quad. ; 8, long head of 

 triceps, hypothenar muscles, interossei, deep thenar 

 muscles. 



In the cutaneous nerve supply of tlie fingers, it 

 must be remembered that on the palmar aspect the 

 thumb, the two outer fingers, and the radial side of 

 the ring finger are supplied by the median, the 

 remaining one and a half fingers by the ulnar (Fig. 

 29). On the dorsal aspect the thumb is supplied by 

 the radial, the index and middle fingers are supplied 

 (as far as the base of the second phalanx) by the 

 radial, and over the second and third phalanges by 

 the median. The little finger and the ulnar side of 

 the ring finger are supplied by the ulnar. The 

 radial side of the ring finger, as far as the base 

 of the second phalanx, is supplied by the radial, and 

 the rest of this side of the digit by the median (Fig. 

 29). The cleft between the middle and ring fingers 

 is occasionally supplied by the ulnar, or partly by the 

 ulnar and partly by the radial. 



Injuries to the main nerves of the upper 

 limb. The entire brachial plexus has been ruptured, 

 leading to complete paralysis of the upper limb. In 

 these cases it would appear that the nerves are torn 

 away from their attachments to the cord rather than 

 broken across at some distance from it. In several 

 instances the biceps muscle has retained some of its 

 functions, while the whole of the other muscles have 

 been paralysed, a circumstance perhaps explained by 

 the high origin of the bicipital nerve from the spinal 

 cord. 



Paralysis of the musculo-spiral nerve. 

 When complete, the hand is flexed and hangs flaccid 

 (" drop wrist "), and neither the wrist nor the fingers 



