1 82 SURGICAL APPLIED ANATOMY. [Chap. xi. 



which the axillary space is mainly occupied is very 

 loose, and, while this laxity favours greatly the free 

 movement of the arm, it at the same time permits of 

 the formation of large purulent collections and im- 

 mense extravasations of blood. 



It is important to remember the disposition of 

 the fasciae about this region. There are three layers 

 principally concerned. (1) The deep pectoral fascia 

 that covers in and encloses the pectoralis major. 

 (2) The clavi-pectoral fascia that, adherent above to 

 the clavicle, fills in the space between that bone and 

 the pectoralis minor, then splits to invest this muscle, 

 and joins the deep pectoral layer at the anterior fold 

 of the axilla to form with it the axillary fascia. The 

 upper part of this fascia is generally known as the 

 costo-coracoid membrane. The whole membrane is 

 sometimes known also as " the suspensory ligament of 

 the axilla," since it draws up the axillary fascia towards 

 the clavicle, and is mainly instrumental in producing 

 the " hollow " of the armpit. (3) The axillary fascia, 

 that is formed by the union of the two preceding 

 fasciae, and stretches across the base of the axilla from 

 its anterior to its posterior fold. 



Abscess about the axillary region may be 

 considered (1) when it is beneath the pectoralis major, 

 or between the two pectoral muscles, and (2) when it is 

 beneath the pectoralis minor and clavi-pectoral fascia, 

 and therefore in the axillary space. (1) An abscess 

 in this situation is placed between the deep pectoral 

 and the clavi-pectoral fasciae, the latter separating 

 it from the axillary space. Such an abscess under- 

 mines the great pectoral, and tends to present either 

 at the anterior margin of the axilla, or in the groove 

 between the great pectoral and deltoid muscles, being 

 guided thither by the attachment of the fasciae. 

 (2) A purulent collection in the axilla may soon fill 

 that space and distend it entirely. Its progress 



