AXILLARY ARTERY BRANCHES. 



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axillary space from the lower border of the first rib to the lower border of 

 the latissimus dorsi, where it becomes the brachial. 



Relations. After emerging from beneath the margin of the costo-cora- 

 coid membrane, it is in relation with the axillary vein, which lies at first 

 to the inner side, and then in front of the artery. Near the middle of the 

 axilla it is embraced by the two heads of the median nerve, and is covered 

 in by the pectoral muscles. Upon the inner or thoracic side it is in rela- 

 tion, first, with the first intercostal muscle ; it next rests upon the first 

 serration of the serratus magnus ; and is then separated from the chest by 

 the brachial plexus of nerves. By its outer or humeral side it is at first 

 separated from the brachial plexus by a triangular interval of areolar tis- 

 sue ; it next rests against the tendon of the subscapularis muscle ; and 

 thirdly, upon the coraco-brachialis muscle. 



The relations of the axillary artery may be thus arranged : 



In Front. Inner or Thoracic Side. Outer or Humeral Side. 



First intercostal muscle, Plexus of nerves, 



Tendon of sub- 



Pectoralis major, 

 Pectoralis minor, 

 Pectoralis major. 



First serration of serra- 

 tus magnus, 

 Plexus of nerves. 



scapularis, 

 Coraco-brachialis. 



Branches. The branches of the Axillary artery are seven in number : 



Thoracica acromialis, Fig. 150.* 



Superior thoracic, 



Inferior thoracic, 



Thoracica axillaris, 



Subscapular, 



Circumflex anterior, 



Circumflex posterior. 



The thoracica acromialis and superior 

 thoracic are found in the triangular space 

 above the pectoralis minor. The inferior 

 thoracic and thoracica axillaris, below the 

 pectoralis minor. And the three remaining 

 branches below the lower border of the sub- 

 scapularis. 



The Thoracica acromialis is a short trunk 

 \vhich ascends to the space above the pec- 

 toralis minor muscle, and divides into three 

 branches, thoracic, which is distributed to 

 the pectoral muscles and mammary gland ; 

 acromial, which passes outwards to the 

 acromion, and inosculates with branches of 

 the supra-scapular artery; and descending, 

 which follows the interspace between the 

 deltoid and pectoralis major muscles, and 

 is in relation with the cephalic vein. 



* The axillary and brachial artery, with their branches. 1. The deltoid muscle. 2 

 The biceps. 3. The tendinous process given off from the tendon of the biceps, to .he 

 deep fascia of the fore-arm. It is this process which separates the median basilic vein 

 from the brachial artery. 4. The outer border of the brachialis anticus muscle. 5. Thf 

 supinator longus. 6. The coraco-brachialis. 7. The middle portion of the trice n* 



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