324 VARIETIES OF THE AXILLARY ARTERY. 



chest. At about an inch and a half from the axillary, it gives off a 

 large branch, the dorsalis scapulae, which passes backwards through 

 the triangular space bounded by the teres minor, teres major, and sca- 

 pular head of the triceps, and beneath the infra-spinatus to the dorsum 

 of the scapula, where it is distributed, inosculating with the supra- 

 scapular and posterior scapular arteries. 



The Circumflex arteries wind around the neck of the humerus. The 

 anterior, very small, passes beneath the coraco-brachialis and short 

 head of the biceps, and sends a branch upwards along the bicipital 

 groove to supply the shoulder-joint. 



The Posterior circumflex, of larger size, passes backwards through 

 the quadrangular space bounded by the teres minor and major, the 

 scapular head of the triceps and the humerus, and is distributed to the 

 deltoid muscle and joint. Sometimes this artery is a branch of the 

 superior profunda of the brachial. It then ascends behind the tendon 

 of the teres major, and is distributed to the deltoid without passing 

 through the quadrangular space. The posterior circumflex artery 

 sends branches to the shoulder-joint. 



Varieties of the axillary Attery. The most frequent peculiarity 

 of this kind is the division of the vessel into two trunks of equal size : 

 a muscular trunk, which gives off some of the ordinary axillary 

 branches and supplies the upper arm, and a continued trunk, which 

 represents the brachial artery. The next most frequent variety is the 

 high division of the ulnar which passes down the arm by the side of 

 the brachial artery, and superficially to the muscles proceeding from 

 the inner condyle, to its ordinary distribution in the hand. In this 

 course it lies immediately beneath the deep fascia of the fore-arm, and 

 may be seen and felt pulsating beneath the integument. The high 

 division of the radial from the axillary is rare. In one instance, I saw 

 the axillary artery divide into three branches of nearly equal size, 

 which passed together down the arm, and at the bend of the elbow 

 resolved themselves into radial, ulnar, and interosseous. But the 

 most interesting variety, both in a physiological and surgical sense, is 

 that described by Dr. Quain, in his " Elements of Anatomy." " I 

 found in the dissecting-room, a few years ago, a variety not hitherto 

 noticed ; it was at first taken for the ordinary high division of the 

 ulnar artery. The two vessels descended from the point of division at 

 the border of the axilla, and lay parallel with one another in their 

 course through the arm ; but instead of diverging, as is usual, at the 

 bend of the elbow, they converged, and united so as to form a short 

 trunk which soon divided again into the radial and ulnar arteries in 

 the regular way." In a subject, dissected by myself, this variety ex- 

 isted in both arms ; and I have seen several instances of a similar 

 kind. 



