38 Anatomy Applied to Medicine and Surgery. 



to two compartments, one bounded in front by the pec- 

 toralis major with its two layers of fasciae ; behind by 

 the clavi-pectoral fascia enclosing the pectoralis minor ; 

 above by the clavicle ; and below by the union of the 

 clavipectoral fascia with the fasciae of the pectoralis 

 major ; the othe? having the boundaries of the axilla 

 proper, excepting in front where the pectoralis major is 

 replaced by the clavipectoral fascia. The knowledge of 

 these divisions of the axillary fasciae .is of practical 

 benefit in connection with abscess in this region. If the 

 pus be in the anterior compartment it would be walled in 

 by the boundaries above mentioned and from the influence 

 of gravity would appear at the most dependent part, viz., 

 along the lower border of the pectoralis major as a deep- 

 seated ridge or swelling ; or, if the patient remained more 

 or less in the recumbent position, at the outer edge of the 

 pectoralis major, i.e., in the groove bet ween the pectoralis 

 major and the deltoid muscle. 



Should, however, the collection be in the axilla proper 

 it would be retained there by the boundaries of that space 

 viz., anteriorly by the clavi-pectoral fascia enclosing the 

 pectoralis minor, externally by the coraco-brachialis, 

 the biceps and humerus, internally by the ribs, intercostals 

 and serratus magnus, and postero-externally by the sub- 

 scapularis, teres major and the latiss. dorsi. The base 

 formed by the axillary fascia proper, and the posterior 

 angle formed by the junction of the serratus magnus and 

 the subscapularis prevent the passage of the pus by these 

 routes. Hence the only outlet is the apex and through 

 this the fluid may find its way under the clavicle and into 

 the neck, or by following the blood vessels, into the me- 

 diastinum. 



The Structures contained in the axilla are: lymphatic 

 glands, axillary artery and vein with their branches, 



