AXILLARY SPACE 



In the medial wall are parts of the upper five ribs with 

 the intervening intercostal muscles ; they are covered by the 

 corresponding digitations of the serratus anterior muscle. 



The lateral wall is formed by the humerus and the conjoined 

 proximal parts of the coraco-brachialis and the short head of 

 the biceps brachii muscles. 



At the apex of the space is the narrow triangular interval 

 through which the axilla communicates with the neck ; it is 

 frequently called the cervico- axillary canal. It is bounded 

 anteriorly by the clavicle, medially by the outer border of 

 the first rib, and posteriorly by the superior margin of the 

 scapula ; through it pass the axillary vessels and the big 

 nerve cords of the brachial plexus on their way from the 



1. Proximal end 



humerus. 



2. Scapula. 



3. Rib. 



4. Pectoralis major. 



5. Serratus anterior. 



6. Subscapularis. 



7. Axillary vein. 



of 



8. Axillary artery. 



9. Long heafl of biceps. 

 10. Conjoined origin of 



short head of biceps 

 and coraco - brachi- 

 alis. 

 n, 12, 13. Brachial nerves. 



FIG. ii. Diagram of section through the Axilla of the Left Side. 



neck to the arm. The wide base or floor of the space is 

 closed by the vaulted axillary fascia. 



Contents of the Axilla. The axillary artery and vein, 

 with the large brachial nerves, which supply the superior 

 extremity, and the axillary lymph vessels and lymph glands, 

 are the most important contents of the axilla. They are 

 all embedded in the soft axillary fat. Except at the apex 

 of the space, the great vessels and nerves lie close to the 

 lateral wall, and follow it in all the movements of the arm. 



Dissection. Cut through the clavicular fibres of the pectoralis 

 major, immediately below their attachment to the clavicle, and 

 turn them towards their insertion. At the same time, secure the 

 branches of the lateral anterior thoracic nerve which pass into 

 the deep surface of the muscle. Follow the cephalic vein and 

 the deltoid branch of the thoraco-acromial artery medially, under 

 cover of the clavicular part of the pectoralis major, and secure the 

 acromial and pectoral branches of the latter artery. Clean those 

 vessels and, directly below the clavicle, display the costo- 

 coracoid membrane, and, more inferiorly and laterally, the fascia 



