500 NERVOUS SYSTEM. 



at its greatest point of separation. At the elbow, it is behind 

 the internal condyle, in the groove between it and the olecra- 

 non, and separates the two heads of the flexor ulnaris muscle. 

 It then gets to the fore arm between this muscle and the flexor 

 profundus digitorum, and continues between them to within 

 two inches of the wrist joint, when it detaches the Ramus Dor- 

 salis. 



The Ramus Dorsalis dips between the ulna and the tendon 

 of the flexor ulnaris, runs along*the internal margin of the ulna 

 to the carpus; it then divides into ramuscles, which supply the 

 ulnar side of the integuments on the back of the hand, and on 

 the backs of the last two fingers. At the interval behind, be- 

 tween the heads of the metacarpal bones of the middle and 

 ring ringers, a considerable ramuscle joins one from the branch 

 of the muscular spiral nerve which attended the radial ar- 

 tery. 



The Ulnar Nerve, having given off this dorsal branch, de- 

 scends along the radial margin of the tendon of the flexor ul- 

 naris and the os pisiforme, above the annular ligament, to the 

 palm of the hand. Getting beneath the aponeurosis, it there 

 detaches first a deep-seated branch, which penetrates the mus- 

 cles of the little finger to supply them, the interossei, and the 

 short flexor of the thumb. The ulnar nerve then furnishes a 

 superficial branch, and afterwards divides into three; one for 

 the ulnar side of the little finger, another for the opposing sides 

 of the little and ring finger, and a third which joins the most 

 internal digital branch of the median nerve. 



SECT. II. OF THE THORACIC SPINAL NERVES. 



The Dorsal or Thoracic Spinal Nerves (Neroi Thoracici, 

 Dorsales) consist in twelve pairs, the first pair goes through 

 the intervertebral foramen, between the first and the second 

 dorsal vertebra, and the twelfth pair between the last dor- 

 sal and the first lumbar vertebra. The common trunk, formed 

 after the ganglion of each nerve, goes but a short distance when 

 it divides into an anterior and a posterior branch. 



The Posterior Branch (Ramus Dorsalis) of each nerve, 



