864 THE NERVES. 



the subscapularis muscle, to the intei-stice between it and the teres major, where 

 it crosses the subscapular arteiy. It proceeds behind the scapulo-humeral 

 articulation, along with the circumflex artery, entere between the teres minor 

 and the caput magnum and medium, and, arriving beneath the deltoid, it 

 divides into several diverging branches, destined to the teres minor, deltoid, 

 mastoido-humeralis, and even to the integuments covering the anterior region 

 of the arm. 



Before entering the space that lodges the subscapular artery, it sends filaments 

 to the scapulo-humeralis and gracilis muscle. 



8. Neeve of the Teres Major (Fig. 465, 12). 



This arises from the eighth cervical pair — like the preceding— by the one 

 trunk, and passes backward, at first on the subscapularis muscle, then on the 

 adductor, in the substance of which it disappear by numerous filaments. 



9. Subscapular Branches (Fig. 465, 14). 



These branches are two in number, and are generally derived from the trunk 

 of the seventh pair. After a short course backwards, they divide into several 

 ramuscules, which pass among the fibres of the subscapularis muscle. 



10. Supra-scapular Nerve (Fig. 465, 15). 



Very short and thick, this nerve is formed by the sixth and seventh cervical 

 pairs. After a brief course backwards, between the levator anguli scapulge on 

 the one side, and the anterior deep pectoral, prescapularis, and supra-spinatus on 

 the other, it gains the space between the latter muscle and the subscapularis, 

 and enters it a little above the supra-scapular artery. It is then carried to the 

 external face of the scapula, after bending round the anterior border of that 

 bone, passes across the acromion spine, and ascends to the infra-spinous fossa, to 

 expend itself in the muscle occupying this space. On its passage beneath the 

 supra-spinatus muscle, it gives it several ramuscules. 



11. Anterior Brachial or Musculo-cutaneous Nerve (Fig. 465, 17). 



This nerve proceeds from the seventh and eighth cervical pail's, descends to 

 the internal face of the scapulo-humeral articulation, and meets the axillary 

 artery, which it crosses outwardly, at an acute angle. It then joins the median 

 nerve by a large short branch, that passes beneath the artery and forms a loop 

 around it ; descending in front of the median nerve, to the bifurcation of the 

 coraco-humeralis, it insinuates itself between the two branches of that muscle, 

 and, breaking up into several ascending and descending ramuscules, enters the 

 substance of the biceps. It also furnishes filaments to the coraco-humeralis, 

 before its passage between the two branches of that muscle. Besides this, it 

 concurs, by a small branch, in the formation of one of the anterior thoracic nerves. 



12. Eadial (or Musculo-spiral) Nerve (Figs. 465, 16 ; 466, 3). 



This is certainly the largest nerve furnished by the brachial plexus. It arises 

 chiefly from the first dorsal pair, and is directed backwards and downwards, on 

 the inner face of the subscapularis and teres major muscles, crossing their 

 direction. In this portion of its course, it proceeds parallel to the humeral 



