3 



THE SUPERIOR EXTREMITY 



INNER 



CORD 



which fills in the gap in the deep stratum of the anterior axillary 

 wall between the subclavius above and the pectoralis minor 

 below (Fig. 9). 



The Costo-Coracoid Membrane is attached medially to 

 the first costal cartilage, laterally to the coracoid process, while, 

 below, it splits to enclose the pectoralis minor. At its medial 



end, it lies behind the clavi- 

 cular head of the pectoralis 

 major ; at its lateral end, it 

 constitutes the floor of the 

 superficial infra-clavicular 

 triangle. The infra-clavicular 

 lymph glands lie on its an- 

 terior surface.and it is pierced 

 by the cephalic vein (p. 50), 

 the thoraco-acromial (thor- 

 acic axis) artery and vein, 

 and the lateral anterior thor- 

 acic nerve. The axillary 

 sheath lies behind the mem- 

 brane, separated from it by 

 the loose fat and the apical 

 lymph glands of the axilla. 

 It is here that the surgeon 

 ligatures the first part of the 



FIG. 9. Diagram of a Section through ax iH arv arterv taking the 

 the Anterior Wall nfthP Avilla aXUJOTy drtery, taKing 



thoraco-acromial artery as 

 his guide. 



At the lower border of the 

 costo-coracoid membrane the 

 clavi-pectoral fascia splits to 

 enclose the pectoralis minor, 

 and the layer on the anterior surface of the muscle is intimately 

 connected to the fascia on the deep surface of the pectoralis 

 major. Below the pectoralis minor the two layers of the clavi- 

 pectoral fascia fuse to form a single sheet, which passes down 

 to join the axillary fascia and is termed the suspensory ligament 

 of the axilla. This layer of fascia is attached laterally to the 

 deep fascia of the arm, in front of the great vessels and nerves. 

 The Thoraco-Acromial (Thoracic Axis) Artery arises from 

 the second part of the axillary artery, pierces the medial 

 part of the costo-coracoid membrane, close to the upper border 



the Anterior Wall of the Axilla. 



T A -r T . 



L.A. f. Lateral anterior thoracic nerve. 



I.A.T. Medial anterior thoracic nerve. 



ART. Axillary artery, second part. 



P. MA. Pectoralis major muscle. 



P. Mi. Pectoralis minor muscle, connected 



by costo-coracoid membrane with 

 SCL. Subclavius muscle. 

 CL. Clavicle. 



