THE BRACHIAL ARTERY 651 



and the medial head of the triceps. The coraco-brachialis muscle lies along the 

 front of the artery, which, however, overlaps the muscle distally. The vein crosses 

 the medial face of the artery and runs down behind it, accompanied part way by the 

 ulnar and radial nerves. The chief branches are as follows: 



1. The suprascapular artery (A. thoraco-acromialis) is a small and somewhat 

 flexuous vessel, which arises near the anterior border of the subscapularis, runs 

 dorsally, and dips in between that muscle and the supraspinatus. It gives branches 

 to these muscles, the anterior deep pectoral, and the brachiocephalicus. A branch 

 passes in front of the coraco-brachialis to the shoulder joint and the proximal end 

 of the humerus. 1 



2. The subscapular artery (A. subscapularis) is a very large vessel which arises 

 at the posterior border of the subscapularis muscle. It ascends in the interstice 

 between that muscle and the teres major, on the medial surface of the long head 

 of the triceps, turns around the posterior border of the scapula below the dorsal 

 angle, and ends in the infraspinatus and deltoid. Besides collateral muscular 

 branches (Rami musculares) to the subscapularis, teres major, triceps, and tensor 

 fasciae antibrachii, it gives off the following named branches : 



(a) The thoraco-dorsal (A. thoracodorsalis) is a long artery which is usually 

 given off about an inch from the origin of the subscapular, crosses the medial face 

 of the teres major, and runs upward and backward on the latissimus dorsi. It gives 

 branches to these muscles, the abdominal cutaneus and the axillary lymph glands. 



(6) The posterior circumflex artery of the humerus (A. circumflexa humeri 

 posterior) arises a little above the preceding vessel, and passes outward behind the 

 shoulder joint between the long and lateral heads of the triceps with the axillary 

 nerve. It gives branches to these muscles, the joint capsule, and the muscles and 

 skin of the lateral side of the shoulder, anastomosing with the anterior circumflex 

 artery. 



(c) The circumflex artery of the scapula (A. circumflexa scapulae) arises about 

 two or three inches (ca. 5-7.5 cm.) above the shoulder joint, passes forward to 

 the posterior border of the scapula, and divides into two branches. The lateral one 

 runs forward on the lateral surface of the scapula below the spine, and gives branches 

 to the supraspinatus, infraspinatus, and teres minor. The medial branch passes 

 forward in a similar fashion on the costal surface of the scapula and supplies branches 

 to the subscapularis. 



3. The anterior circtomflex artery of the humerus (A. circumflexa humeri 

 anterior)^ arises usually at the anterior border of the teres major. It passes forward 

 between the two parts of the coraco-brachialis or between the latter and the humerus. 

 It gives branches to the coraco-brachialis and deep pectoral and ends in the upper 

 part of the biceps and in the brachiocephalicus. It anastomoses with the posterior 

 circumflex artery. 



Not rarely it is replaced largely by an artery which arises from the brachial at the distal end 

 of the coraco-brachialis, and ascends on the front of the humerus. In these cases a sraall branch 

 for the coraco-brachialis is usually given off at the usual point of origin of the anterior circumflex. 



4. The deep brachial artery (A. profunda brachii) is a large but short trunk 

 which arises usually about the middle of the humerus. It passes backward to the 

 interval between the tendon of the teres major and latissimus dorsi, and the long and 

 medial heads of the triceps, where it divides into several branches which supply the 

 triceps, tensor fasciae antibrachii, anconeus, and brachialis. A branch runs in the 

 musculo-spiral groove with the radial nerve to the front of the elbow joint and 

 anastomoses with the anterior radial. A slender branch descends along the lateral 



1 This vessel may be double, or be represented by one or more branches of the inferior cervical 

 artery. 



2 Also termed the prehumeral artery. 



