PLATE H. 

 THE AXILLA, DEEP VIEW. 



The pectoralis major has been cut across about its centre, and thp ends turned 

 imvards and outwards in order to expose the pectoralis minor and the deeper parts of 

 the axilla. The costo-coracoid membrane was extremely thin, and was removed with 

 the fibro-aivnlar tissue lying between its lower edge and the upper border of the 

 pectoralis minor ; the sheath of the vessels was also removed. It is a deeper dissection 

 of the same axilla, as in Plate I. The plate shows well the doubling up of the 

 fibres of the pectoralis major at their insertion, the inferior fibres of origin being 

 folded up so as to lie beneath the upper ones, thus having a higher insertion into the 

 humerus along the outer border of the bicipital groove. 



It also shows a fibrous intersection, not uncommonly found running between the 

 pectoralis minor and the coraco-brachialis muscles from the tip of the coracoid process. 



In this body the intercosto-humeral, instead of giving a branch to join the nerve of 

 \Yrislierg (6), receives one from it (16), the nerve of Wrisberg being much larger than 

 usual. 



The costo-coracoid membrane is a fibrous structure, varying much in thickness in 

 different subjects, which is attached above to the borders of the inferior surface of the 

 clavicle, thus enclosing the suhclavius muscle. Its lower border is condensed into a 

 fibrous band, the costo-coracoid ligament, which stretches between the cartilage of the 

 first rib and the coracoid process. The membrane is stronger externally, forming a 

 fairly strong band between the clavicle and the coracoid process. Its deep surface is 

 blended with the sheath of the axillary vessels. This latter is funnel-shaped and derived 

 from the deep cervical fascia covering the scaleni muscles. 



The costo-coracoid ligament is a representative of the prolonged coracoid element 

 seen in monotremes, etc. ; it frequently contains cartilage nodules. (Bland Sutton.) 



