AXILLARY SPACE 35 



A. thoracalis suprema \from the 



J first part. 



A. thoraco-acromialis"\ from the 



A. thoracalis lateralis/ second part. 



A. subscapularis . *j 



A. circumflexa I f 



humeri anterior I the 

 A. circumflexa third P art " 



humeri posterior 





Arteria Thoracalis Suprema (O.T. Superior Thoracic). 



The supreme thoracic artery is a small branch which springs 

 from the axillary at the lower border of the subclavius. It 

 ramifies upon the upper part of the medial wall of the axilla 

 and supplies twigs to adjacent structures (Fig. 15). 



Art. Thoraco-acromialis (O.T. Acromio-thoracic or Thoracic 

 Axis). The thoraco-acromial artery is a short, wide trunk, 

 which takes origin under cover of the pectoralis minor. It 

 winds round the upper border of that muscle, pierces the costo- 

 coracoid membrane, and immediately divides into branches ; 

 the branches receive different names, and are arranged as 

 follows : (a) The clavicular branch, a small twig, which runs 

 upwards to the clavicle and then turns medially along that 

 bone, between the clavicular part of the pectoralis major and 

 the costo-coracoid membrane, (b) The pectoral branches, of 

 larger size, run downwards between the two pectoral muscles ; 

 they give branches to both muscles, and they anastomose with 

 the lateral thoracic and the lateral branches of the intercostal 

 arteries, (c] The acromial branch runs laterally, upon the 

 tendon of the pectoralis minor and the coracoid process. 

 Some of its twigs supply the deltoid, whilst others pierce it to 

 reach the superior surface of the acromion. It anastomoses 

 with the transverse scapular (O.T. suprascapular) and posterior 

 humeral circumflex arteries. (d) The deltoid branch, as a 

 rule, takes origin from a trunk common to it and the pre- 

 ceding artery. It runs distally in the intermuscular interval 

 between the pectoralis major and the deltoid, and supplies 

 both muscles. 



Arteria Thoracalis Lateralis. The lateral thoracic artery 

 takes the lower border of the pectoralis minor as its guide, 

 and proceeds downwards and medially to the side of the 

 thorax. It gives branches to the neighbouring muscles. 

 It anastomoses with twigs from the intercostal arteries, 

 and it also supplies the mamma, giving off, as a rule, an 

 external mammary branch, which winds round or pierces 

 the lower border of the pectoralis major on its way to the 

 gland. 



