THE AXILLARY ARTERY 



571 



thoraco-acromial, or a little above. It passes behind the axillary vein across the 

 first intercostal space, supplying the intercostal muscles and the upper portion 

 of the serratus anterior, and anastomoses with the intercostal arteries. At 

 times it sends a branch between the pectoralis major and minor, which then, as a 

 rule, more or less takes the place of the pectoral branch of the thoraco-acromial 

 (figs. 464 and 465). 



2. The thoraco-acromial or acromio -thoracic axis [a. thoracoacromialis] 

 arises from the front part of the axillary just above the upper border of the 

 pectoralis minor. It is a short trunk, and, coming off from the front of the 

 artery, pierces the coraco-clavicular fascia, and then divides into three or four small 

 branches, named from their direction: — ia) the acromial; (b) the deltoid; (c) the 

 pectoral, and {d) the clavicular. 



Fig. 465. — ^The Branches op the Axillary Artery. (After Hitzrot.) 

 The numbers 1-5 indicate the intercostal spaces. 



Thoraco-acromial 

 Superior thoracic i Clavicular branch 



Acromial branch 



Pectoral branch 



Deltoid branch 



Branch to serratus 

 anterior 



Anterior circumflex 



humeral 

 Posterior circumflex 

 humeral 



Subscapular 



Branch to teres major 



Branch to serratus 

 anterior 



Branches to latissimus dorsi 



Branch to serratus anterior 



(a) The acromial branch [r. acromialis] or branches pass laterally across the coracoid 

 process, frequently through the deltoid muscle, which they in part supply, to the acromion, 

 where they form, by anastomosing with the anterior and posterior circumflex and transverse 

 scapular (suprascapular) arteries, the so-called acromial rete, or plexus of vessels on the surface 

 of that process. 



(6) The deltoid branch [r. deltoideus] runs downward with the cephahc vein in the interval 

 between the pectoraUs major and the deltoid, and, supplying lateral offsets to these muscles 

 and the adjacent integument, anastomoses with the anterior and posterior circumflex humeral 

 arteries. 



(c) The pectoral branch [r. pectoralis] passes between the pectoraUs major and minor 

 muscles, both of which it supphes. In the female, one or more branches which perforate the 

 pectoralis major are often of large size, and supply the superimposed mammary gland. 



(d) The clavicular branch passes upward beneath the clavicle, supphes the subclavius 

 muscle, and anastomoses with the transverse scapular artery. 



3. The lateral thoracic artery [a. thoracalis lateralis] descends along the lower 

 border of the pectoralis minor, under cover of the pectoralis major, to the chest 

 wall. It supplies both pectoral muscles and the serratus anterior (magnus), 

 sends branches around the lower border of the pectoralis major to the mammary 

 gland, and terminates in the intercostal muscles by anastomosing with the aortic 

 intercostals and the internal mammary. It also furnishes branches to the 

 lymph-nodes of the axillary fossa. The branches to the mammary gland in the 

 female are often of large size. 



4. The subscapular artery [a. subscapularis] is the largest branch of the 

 axillary. It arises opposite the lower border of the subscapularis, and runs in a 



