BRANCHES OF BRACHIAL PLEXUSES 



'SU 



and luuisc'ulu-cutaiicous arc iiioiv proxiiual in tlifir distribution than the median, 

 ulnar, and nmsculo-spiral, and may therefore be first described. 



(1) The circumflex nerve is a brancli of the posterior cord, and is composed of 

 fibres derived from the lifth and sixth cervical nerves. It accompanies the i)osterior 

 circumflex artery through tlie (piadrilateral space bounded by the teres major, long 

 head of triceps, and subscai)ularis muscles, and by the surgical neck of the humerus, 

 and it divides into a smaller ])osteri()r and a larger anterior division. Previous to 

 its division it furnishes an articular twig to the shoulder joint. This twig ])ierces the 

 inferior i)art of the ca])sular ligament. 



(a) Th{> anterior division accompanies the ])osterior circumflex artery around 

 the neck of the humerus, and gives off a number of stout twigs which enter the 



Fig. 456.— Distribution of Cutaneous Xervks on the Anterior and PosTERiort Aspects 



OF the Superior Extremity. 



INTERNAL 

 CUTASEOirs OF 

 .Vl'SCULO- 

 SPIKA /, 



INTERNAL 

 CUTANEOUS 



PA LMA R 



rUTANEOUa OF 



MEDIAN 

 PALMAR 



CUTANEOUS OF 



ULNAR 



SUPRA- 



ACROMIAL 



CIRCUMFLEX 



CIRCUM- 

 FLEX 



CUTANEOVS 



EXTERXAL 

 CI'TANEOUS OF 



MUSCCLO- 



SPIRAL 



MUSCULO- 

 CUTANEOUS 



EXTERNAL 



CUTANEOUS 



OF 



MUSCULO- 



SPIRAL 



RADIAL 



PALMAR 

 CfrTANEOUS 

 OF RADIAL 



SUPRA- 



A CROMIA L 



IXTERSAL 

 CITASKOrS O 



MUSCrLU- 



SPIRAL 

 ISTERCOSTO- 



HUMERAL 



NER VE OF 

 WRISBERC 



INTERNAL 

 CUTANEOUS 



ULNAR 



deltoid muscle. A few fine filaments pierce the deltoid and end in the integiunent 

 which covers the middle third of that muscle. 



(fe) The posterior division divides into cutaneous and muscular branches. 

 The cutaneous branch sup})lies the skin covering the lower third of the deltoid and 

 a small area of integument below the insertion of that muscle. One muscular 

 branch is distributed to the teres minor; it swells out into an ovoid or fusiform 

 reddish gangliform enlargement before entering the muscle, others sui)]ily the 

 lower and {posterior ))art of the deltoid. 



(2) The lesser internal cutaneous nerve, or nerve of Wrisberg, arises from 

 the inner cord of the lirachial i)lexus. and is formed of fibres derived from the 

 eighth cervical and first thoracic nerves or from the first thoracic nerve alone. It 

 runs downwards on the inner side of the axillary vein, being separated bv that 



