THE VESSELS. 315 



b. Thoracica 11. s. acromialis arises generally in common with a and divides 

 into : 



1. Ram. deltoideus, which passes close to Ven. cephalica downwards in 

 a groove of uniting tissue between m. pectoralis and deltoid, and ter- 

 minates in the last. 



2. Ham. acromialis passes away, covered by m. deltoideus, transversely 

 outwards, above proc. coracoid., lig. coraco-acromiale, and the exter- 

 nal extremity of the anterior border of the clavicula to the shoulder- 

 joint ; anastomoses with transvers. scapula. 



562. Below the pectoralis minor : 



c. Thoracica 111., s. longa, s. inferior, s. mammaria externa, passes down- 

 wards and forwards on the side of the thorax between m. pectoral, major 

 and serratus magnus, then between this and the skin, terminating on 

 the sixth intercostal space ; it gives branches to the axillary and mam- 

 mary glands, the muscles of the second to the sixth intercostal spaces. 



563. Branches of the axillaris at the collum humeri. 



d. Subscapularis. The largest branch of axillaris arises from the outer 

 side of it between IV. radialis (within) and N. medianus (without). 

 Course : curved outwards and downwards, parallel with m. teres major, 

 on the anterior (external) border of the scapula. Position : before m. 

 scapularis. Branches : to m. scapularis, teres major, and two terminal 

 branches. 



1. Art. thoracico-dorsalis passes downwards along the anterior border 

 of the Scapula, behind Art. thoracica longa, between latissim. dorsi 

 and serratus anticus, and ramifies in them. 



2. Art. circumflexa scapula, before the long head of m. triceps, turns 

 round the attachment of this to the anterior border of the Scapula 

 backwards to the fossa infraspinata, covered by m. infraspin., sends 

 an anterior branch between fossa and m. sub scapular is, and anasto- 

 moses with art. transversa scapul. (above) and thoracico-dorsalis 

 (below). 



e. Circumflexa humeri anterior, small, arises on the anterior outer side of 

 axillaris, often in common with the following. Course : transversely 

 outwards above the tendons of latissim. dorsi and teres major, around the 

 anterior surface of collum humeri backwards. Situation : behind coraco- 

 brachial. and biceps. Branches to collum humeri [and head, gives off the 

 epiphysial artery.] 



f. Circumflexa humeri posterior; larger. Origin: at the posterior outer side 

 of axillaris, opposite to subscapularis. Course : transversely backwards 

 and outwards round the posterior surface of collum humeri to the outside 

 of it ; terminates in m. deltoideus. Situation : close to Ven. circumfl. and 

 Art. axillaris, before cap. long. m. tricipitis, latissim. dorsi, above teres 



