572 



THE BLOOD-VASCULAR SYSTEM 



downward and medial direction along the anterior border of that muscle under 

 cover of the latissimus dorsi. It supplies the subscapularis, teres major, latissimus 

 dorsi, and serratus anterior (magnus) muscles, and gives branches to the nodes 

 in the axillary fossa. The course of this large vessel along the posterior border 

 of the axillarj'- fossa should be remembered in opening abscesses in the fossa, and 

 in removing enlarged nodes from it. It is accompanied by two veins, which 

 usually unite and then receive the circumflex (dorsal) scapular vein, and open as 

 a single vein of large size either into the axillary or at the confluence of the medial 

 brachial vena comitans "^dth the basilic vein. 



About 2.5 or 3.7 cm. (1 or 1| in.) from its origin, the subscapular artery divides 

 into two end branches, (1) the circumflex (dorsal) scapular, and (2) the dorsal 

 thoracic. 



Fig. 466. — The Anastomoses about the Scapula. 



Subscapular branch of transverse scapular artery 

 Supraspinous branch of transverse scapular artery 



Descending branch 

 of transverse cer- 

 vical artery 



Supraspinous 

 branch 

 Subscapular 

 branch 



Branch of inter- 

 costal artery 



Branch of inter- 

 costal artery 



Continuation of de- 

 scending branch 

 of transverse cer- 

 vical artery 



Transverse scapular artery 



Acromial branch of 

 '" thoraco-acromial 

 Acromial rete 



Subscapular branch of 



transverse scapular 



artery 

 Infraspinous branch of 



transverse scapular 



artery 

 Subscapular branch of 

 axillary artery 



_Circumflex scapular artery 



Infrascapular branch of cir- 

 cumflex scapular artery 



Dorsal thoracic branch of 

 subscapular artery 



(1) The circumflex scapular artery [a. circumflexa scapulae], or dorsal scapular, arising 

 from the subscapular, usually at the point above mentioned, passes backward through tlie trian- 

 gular space bounded by the subscapularis above, the teres major below, and the long head of 

 the triceps laterally, and then between the teres minor and the axillary border of the scapula, 

 which it commonly grooves. It thus reaches the infraspinous fossa, where, under cover of 

 the infra-spinatus, it anastomoses with the transverse scapular (suprascapular) artery and the 

 descending branch of the transverse cervical (i)osterior scapular) (fig. 466). As it passes through 

 the triangular space, it gives off a ventral branch which ramifies between the subscapularis 

 and the bone, supplying branches to the subscapularis, to the scapula, and to the shoulder- 

 joint. A second branch is often given off near the triangular space and passes downward 

 between the teres major and teres minor, supplying both muscles (fig. 467). 



(2) The dorsal thoracic artery [a. thoracodorsalis] continues in the course of the subscapular 

 as far as tlie angle of the scapula, where it anastomoses with the circumflex scapular, the 

 descending branch of the transverse cervical (posterior scapular), the lateral thoracic, and 

 intercostal arteries. 



5. The anterior circumflex humeral artery fa. circumflexa humeri anterior], 

 usually quite a small vessel, comes off from the lateral side of the axillary artery, 

 generally opposite the posterior circumflex. It passes })eneath the coraco- 

 brachialis and short and long heads of the biceps, winding transversely round the 

 front of the surgical neck of the humerus, across the intertubercular (bicipital) 

 groove, and anastomoses with the posterior circumflex and thoraco-acromial 

 arteries. It gives off the following small branches: 



