i64 THE SALAMANDER 



passes round the posterior border of the scapula to its lateral surface, 

 mesial to the M. dorsalis scapulae. The smaller posterior nerve 

 goes entirely to the muscle. The larger anterior nerve gives a few- 

 small twigs to the muscle and then passes to its anterior edge, where 

 it divides into three cutaneous and two muscular branches. The 

 twolatterenter the adjoining edges of the MM. dorsalis scapulae and 

 procoraco-humeralis respectively, while of the cutaneous branches 

 {NN. cutanei brachii superiores later ales ^ 32, Fur.), one (a. Fig. c^^) 

 supplies the skin covering the lateral surface of the arm, while 

 another (j8. Fig. ^^ turns mesially over the procoracoid to the skin 

 of the breast, and the third (y. Fig. ^^) turns dorsally to the skin of 

 the scapular region. 



N. axillaris (n.ax.) (Osawa) is a fairly large cutaneous nerve 

 arising close to the N. dorsalis scapulae. It passes out between the 

 M. dors. scap. and the M. dors, humeralis, and supplies the skin 

 covering them. 



A^. dorsalis humeralis (n.d.h.) (= N. latissimus dorsi, 34, Fiir.) 

 arises from an anastomosis between N. spinales 3 and 4, and appears 

 to receive fibres from both spinal nerves. It passes dorsalwards 

 alongside NN. dors. scap. and axillaris and enters the M. dorsalis 

 humeralis mesially. 



The nerves arising from the brachial plexus distal to this point 

 will be dealt with under the headings 'Extensor nerves' and 'Flexor 



Fourth spinal nerve {ventral branch) (n.sp.4). 



The proximal part of N. spinalis 4, after emerging from the sub- 

 vertebral muscles, gives one or two fine dorsal branches to the 

 M. thoraci-scapularis (= N. thoracicus superior 4, Fur.). Between 

 this point and the plexus one or two fine branches are given off to 

 the M. rectus abdominis. 



Extensor nerves. 



NN. brachiales longi superiores ..... Furbringer. 

 These consist of two^ main nerves which enter the arm posterior 

 to the humerus and shoulder-joint, passing between the heads of the 

 MM. anconeus scapularis medialis and anconeus coracoideus in 

 company with the Vena brachialis medialis. They pass to the dorsal 

 side of the humerus. 



' Fiirbringer reports one anomalous case in which the extensor nerve in the arm was 

 represented by a single large bundle, instead of the two parallel nerves found normally. 



