134 ANTHROPOLOGY. 



to whicli it sends off various muscular and cutaneous branches. The ante- 

 rior or radial nerve supplies the supinator longus muscle, along which it 

 descends, and passing behind its tendon about the middle of the forearm, 

 becomes cutaneous ; continuing in its decent, it divides into two consider- 

 able branches on the back of the head. The deep branch, or the posterior 

 interosseal nerve, is larger than the radical ; winding around the upper part 

 of the radius, it descends along the back part of the forearm, and divides 

 into several branches, superficial and deep, which supply the two layers of 

 extensor muscles. 



PL 137, fig. 16 (see fig. 15, for the four superior cervical nerves), deep 

 cervical nerves; brachial plexus: \ facial nerve; ^, vagus ; ^, internal carotid 

 artery ; *, accessory nerve ; ^, its connexion with the cervical nerves ; ", hypo- 

 glossus ; ', anterior branch of the first cervical nerve, uniting with the hypo- 

 glossus and vagus; ', connecting branches of the second and third cervical 

 nerves with the hypoglossus ; *, phrenic nerve ; '"' '", deep branches of the 

 cervical plexus ; ", brachial plexus ; '*, the nerve for the subclavian muscle 

 giving oft' a branch to the phrenic nerve ; ", anterior thoracic nerve ; '% pos- 

 terior do. ; "' '"' ", branches of the subscapular nerve, to the subscapularis, 

 the latissimus dorsi, and teres muscles ; ", axillary artery, embraced by the 

 brachial plexus ; ", brachial branches of the brachial plexus. 



PI. 138, fig. 1, cutaneous nerves of the arm, on the dorsal side : ', cutane- 

 ous branches from the axillary nerve ; "• ", from the radial nerve ; '■ *, branches 

 of the internal cutaneous; *• ", branches of the external cutaneous; ^, union 

 of one of these branches with the radial nerve; \ dorsal branch of the ulnar 

 nerve with its digital branches ; ', dorsal branch of the radial nerve and its 

 digital branches; ', connecting branches between the radial and ulnar 

 nerves ; ', bifurcation of a digital nerve. Fig. 5, ', trapezius muscle ; ', rhom- 

 boideus do. ; ', accessory nerve; *• % deep posterior branches from the cervical 

 and brachial plexus ; ', supra-scapula nerve ; ', axillary nerve or circumflex 

 nerve of the arm. 



The share of the brachial plexus possessed by each nerve of the superior 

 extremities in the brachial plexus may be expressed as follows, the figures 

 referring to the oth, 6th, 7th, and 8th cervical nerves, and to the 1st dorsal 

 nerves, which together constitute this plexus. 



The supra-scapular nerve, 5, 6, or 5, 6, 7. 



The subscapular nerve, 5, 6, 7, 8, or 5, 6, 7. 



The anterior thoracic, o, 6 ; the posterior often 8, 1. 



The great internal cutaneous nerve of the arm, 8, 1, or 7, 8, 1, or 1. 



The musculo-cutaneous nerve, 5, 6, 7, or 5, 6, or 5, 7. 



The axilliary nerve, 5, 6, 7, or 5, 6, or 5, 6, 7, 8, 1. 



The radial nerve, 5, 6, 7, 8, or 5, 6, 7, 8, 1, or 6, 7, 8, or 6, 7, 8, 1, or 5, 

 6, 7, or 7, 8. 



The ulnar nerve, 5, 6, 7, 8, 1 or 5, 6, 7, 8, or 6, 7, 8, 1, or 6, 7, 8, or 7, 8, 

 1, or 8, 1. 



The median nerve, 5, 6, 7, 8, 1, or 5, 6, 7, 8, or 5, 7, 8, 1, or 6, 7, 8, 1, or 

 5, 6 , 7, 1, or 8, 1. 



The posterior thoracic, 5, 6, 7, 1. 

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