Axillary Artery 247 



mamma. The alar thoracic supplies lymphatic glands as well as the 

 chest-wall, and its branches are useful in the collateral circulation. 



The subscapular is a very large branch. It descends along the 

 axillary border of the muscle which gives it its name, and at last 

 reaches the chest- wall. It gives off a dorsal branch which passes on 

 to the scapula under cover of the teres minor and the infra-spinatus to 

 anastomose with the supra- and posterior scapular arteries of the thyroid 

 axis. 



The circumflex arteries are named from their being ' bent around ' 

 the surgical neck of the humerus. The anterior, the smaller, passes 

 outwards beneath the coraco-brachialis and biceps, and as it runs 

 across the bicipital groove it sends a branch up to the shoulder-joint. 

 It ends by anastomosing with the posterior circumflex, which emerges 

 from the axilla through the quadrilateral space bounded by the 

 humerus and the long head of the triceps at the sides, and the teres 

 minor and major above and below. It supplies the shoulder-joint 

 and the deltoid, and anastomoses with the preceding vessel, and, 

 on the acromion process, with the acromial-thoracic and the supra- 

 scapular. 



Collateral circulation after ligation of the first part of the axillary 

 would be carried on as after ligation of the third part of the subcla- 

 vian (p. 231) ; and after ligation of the lowest part of the axillary 

 as after ligation of the brachial above the point of origin of the 

 superior profunda (p. 265). 



The third part of the axillary artery may be reached and tied by 

 abducting the arm and rotating it outwards. The vessel lies in the 

 upward continuation of the brachial groove, nearer to the anterior 

 axillary fold than the posterior, and along the inner side of the coraco- 

 brachialis. 



A three-inch incision is made through the skin and superficial 

 fascia from well up beneath the insertion of the pectoralis major 

 down into the brachial groove. The deep fascia is divided on a direc- 

 tor, the coraco-brachialis, which is the guide to the artery, being then 

 looked for and followed down. Some more fibrous tissue is traversed 

 by the director and forceps, and the median nerve is then turned out- 

 wards, and the axillary vein is gently separated from the inner side. 

 The internal cutaneous nerve may, perhaps, have to be drawn inwards ; 

 the ulnar nerve will be hidden by the vein as it lies between the vein 

 and artery, and it must be carefully excluded from the ligature, which 

 is passed from the inner side. Sometimes a fleshy bundle passes from 

 the latissimus dorsi over the artery, to be inserted with the pectoralis 

 major ; this might possibly be mistaken for the coraco-brachialis, 

 especially if the incision-wound were small. 



Varieties. Occasionally the axillary gives off the radial or ulnar 

 artery, or a slender i>as aberrans, to join the radial or ulnar below 

 the elbow. Sometimes a large branch runs by the side of the long 



