NERVES OF THE ARM. 515 



The Cubital or Ulnar Nerve 



Is also of considerable size. It passes down on the inside of 

 the triceps extensor muscle, to the great groove formed by the 

 olecranon process and the internal condyle of the os humeri ; 

 and, in this course, it often sends a branch to the triceps, some 

 smaller twigs to the upper part of the fore-arm, and one which 

 piercing the fascia anastomoses with the internal cutaneous. 

 From the groove it proceeds on the anterior part of the fore- 

 arm, between the flexor carpi ulnaris and the flexor sublimis, 

 to the wrist. At a small distance above the wrist it sends off 

 a branch, called the Dorsalis, which passes between the flexor 

 ulnaris and the ulna, to the back of the fore-arm and wrist, 

 where, after sending ramifications to the integuments and con- 

 tiguous parts, it divides into branches which pass to the little 

 finger and the finger next to it. These branches send off, in 

 their course, many twigs which pass to the skin and cellular 

 substance. 



The ulnar nerve then proceeds with the artery, over the 

 annular ligament, on the radial side of the os pisiforme, and 

 divides into two branches ; one of which is called the superfi- 

 cial, and the other the deep-seated palmar. 



The Superficial divides into two principal branches, an 

 external and an internal. The external passes under the apo- 

 neurosis palmaris ; and, after sending a branch to combine 

 with one from the median and some twigs to the contiguous 

 muscle, it subdivides into two branches, one of which goes to 

 the ulnar side of the ring finger and the opposite side of the 

 little finger. The other branch sends off some twigs to the 

 muscles, and proceeds along the ulnar side of the little 

 finger. 



The Deep-seated palmar branch of the ulnar nerve passes 

 between the muscles of the little finger, under the tendons of 

 the flexors, and accompanies the deep-seated arterial arch in 

 the palm of the hand, giving branches to the interossei, and 

 other contiguous muscles. 



