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." 
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 
fascize 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. 
(b) 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 scapulz) 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 circumflex 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. 
Tt 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 small 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 fascize 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 
_ # Also termed the prehumeral artery. 
