n^ 



HUMAN ANATOMY. 



{b) The clavicular branch, which is the smallest of the three, passes upward to supply the 

 subclavius muscle, and anastomoses with the suprascapular artery. 



[c) The acromio-humeral branch passes upward and outward across the costo-coracoid 

 membrane and over the coracoid process of the scapula, and then divides into an acromial and 

 a humeral hranch.. The former (ramus acromialis) passes upward towards the acromial process 

 to supply the deltoid muscle, while the latter (ramus deltoideus) turns downward in the groove 

 between the deltoid and the clavicular portion of the pectoralis major, accompanying the cephalic 

 vein. It sends branches to the two adjacent muscles and to the integument, and anastomoses 

 with the anterior circumflex artery. 



3. The Long Thoracic Artery. — The long thoracic (a. thoracica lateralis) 

 (Fig. 704) is a somewhat inconstant branch, whose place is very frequently taken by 

 the thoracic branch of the acromial thoracic or by a branch from the subscapular. It 

 passes downward and forward upon the serratus magnus, sending branches to that 

 muscle, the pectoralis minor, and the muscles of the third, fourth, and fifth intercostal 



Fig. 707. 



Transverse cervical artery 

 Superficial cervical branch 

 Posterior scapular branch 

 Trapezius, cut 



. Rhomboideus minor 



, Levator anguli scapulre Trapezius Supraspinatus 



Acromion 



Deltoid, everted 



Triceps 



Supra- 

 scapular 

 artery 



Clavicle 



Rhom- 

 boideus 

 major 



Post, circumflex art. 

 Infraspinatus 



Triceps, scapular head 

 Teres minor 

 Spine of scapula 

 Dorsal scapular artery 



Subscapularis 

 Teres major 



Latissinius dorsi 



Arteries of posterior aspect of shoulder. 



spaces. It also sends branches to the mammary gland (rami mammarii externi), 

 whence it has been termed the external mammary artery. It anastomoses with the 

 thoracic branch of the acromial thoracic, with the subscapular and the intercostals, 

 and with the perforating branches of the internal mammary. 



4. The Alar Thoracic Artery.— The alar thoracic (Fig. 704) is a very incon- 

 stant small branch which passes to the fascia and lymphatic glands of the axillary 

 space. Its place may be taken by branches from the subscapular, the long thoracic, 

 or the thoracic branch of the acromial thoracic. 



5. The Subscapular Artery. — The subscapular (a. subscapularis) (Fig. 

 704) is the largest branch of the axillary and arises just as that artery crosses the 

 lowx^r border of the subscapularis muscle. It passes downward and inw^ard, accom- 

 panied by the long subscapular nerve, along the lower border of the subscapular 

 muscle as far as the lower angle of the scapula, and distributes branches through- 

 out its course to the subscapularis and teres major and to the latissimus dorsi. It 

 also gives off — 



