380 



AXILLARY ARTERY. 



branches to the subscapularis, serratus magnus, teres major, and latissimus 

 dorsi muscles. It soon becomes considerably diminished in size, owing to 

 its giving off a large branch to the dorsuin of the scapula. Its final ramifi- 

 cations anastomose with one another and with the branches of the posterior 

 scapular artery. 



The dorsal branch (dorsalis scapulae) turns back from the subscapular 

 artery, about an inch and a half from its origin, and is sometimes larger 

 than the continuation of the vessel. Descending along the lower border of 

 the scapula, it passes through the interval bounded internally by the sub- 

 scapularis and teres minor, externally by the latissimus dorsi and teres 

 major, and superiorly by the long head of the triceps muscle ; and, turning 

 closely round the border of the scapula, which is frequently grooved to 

 receive it, passes between the teres minor and the bone, and ramifies in 

 the iufraspinous fossa, where it anastomoses with the suprascapular and 

 posterior scapular arteries. 



Fig. 267. 



V, 



Fig. 267. VIEW 

 OF THE ARTERIES 

 WHICH RAMIFY AND 

 ANASTOMOSE ON THE 

 VENTRAL SURFACE 

 OF THE SCAPULA, 



AND OF THE AN- 

 TERIOR CIRCUM- 

 FLEX ARTERY (from 

 B. Quain). 



a, coracoid process ; 

 J, tendon of the long 

 head of the biceps 

 muscle emerging from 

 the bicipital groove ; 

 c, the front- of the 

 capsular ligament of 

 the shoulder -joint ; d, 

 tendon of the latissi- 

 mus dorsi muscle ; e, 

 teres major; 1, supra- 

 scapular artery de- 

 scending to the supra- 

 scapular notch, over 



the ligament of which the larger part of the artery passes into the supraspinous fossa ; 

 A, A' the axillary and brachial artery ; 1', its subscapular branch passing through the 

 notch and ramifying in the subscapular fossa ; 2, 2, posterior scapular artery descending 

 parallel to the base of the scapula ; 2', its subscapular branches ; 3, main stem of the 

 subscapular artery at its origin from the axillary and continuation towards the dorsum of 

 the scapula ; 3' the branch to the ventral surface of the scapula proceeding to anasto- 

 mose with the subscapular branches of the suprascapular and posterior scapular arteries ; 

 4, descending or thoracic branch of the subscapular artery ; 5, anterior circumflex artery ; 

 6, posterior circumflex passing back through the quadrilateral muscular space. 



The dorsalis scapulae gives off, (a) ventral branches, slender vessels which 

 ramify in the tmbscapular fossa between the subscapular muscle and the bone, and 

 anastomose with twigs from the suprascapular and posterior scapular arteries; 

 (6) branches to the teres muscles, and particularly a twig which descends between 

 their origins ; (c) terminal branches in the iufraspinous fossa. 



CIRCUMFLEX ARTERIES. The posterior circumflex artery, a considerable 

 vessel but smaller than the subscapular, arises opposite the lower border of 

 the subscapular muscle, below the subscapular artery, and is directed back- 



