THE ARTERIES 169 



parent vessel. Close to its point of detachment from the axillary artery 

 the subscapular artery gives off a branch which is frequently described 

 as the continuation of the subscapular vessel. This branch passes across 

 the ulnar and musculo-spiral nerves, and is then found deeply seated 

 between the subscapularis and teres major muscles. It runs obliquely 

 upwards and backwards along the glenoid border of the scapula, to 

 terminate near the dorsal angle of this bone. During its course this 

 vessel gives off branches which pass into the subscapularis and infra- 

 spinatus muscles, thus embracing between them the glenoid border ot 

 the scapula. From one of these branches the nutrient artery of the 

 scapula is given off. 



The subscapular artery also gives off : 



{a) Branches which are distributed to the teres major muscle. 



{b) A branch which disappears by passing through the triangular 

 space at the back of the shoulder joint beneath the large head of the 

 triceps extensor cubiti muscle in company with the circumflex nerve. 

 This artery is the posterior circumflex of the shoulder, and is sometimes 

 referred to also as the scapulo-humeral artery. Like the terminal ramus- 

 cules of the circumflex nerve, its terminal branches are distributed to 

 the teres minor, deltoid, and mastoido-humeralis muscles, in addition to 

 the panniculus carnosus. 



(c) The Artery to the Latissimus Dorsi Muscle. — This is frequently 

 described as a separate vessel, having a common origin with the sub- 

 scapular artery from the axillary. It leaves the subscapular artery, and 

 passes backwards across the teres major muscle, following at first the 

 inferior border of the latissimus dorsi. It then ascends on the deep 

 face of the latter muscle, and splits up into a number of branches 

 which penetrate the muscle, some of which are also distributed to the 

 panniculus carnosus. 



The position of the axillary artery affords it a considerable degree of 

 protection from injury. It may, however, be damaged or even ruptured 

 in some cases of fractured first rib. Owing to the situation of the vessel, 



Y 



