380 



THE MUSCLES AND FASCIAE 



tendinous digitations from the upper margin and outer surface of the third, fourth, 

 and fifth ribs, near their cartilages, and from the aponeurosis covering the Inter- 

 costal muscles ; the fibres pass upward and outward, and converge to form a flat 

 tendon, which is inserted into the inner border and upper surface of the coracoid 

 process of the scapula. 



Relations. By its anterior surface, with the Pectoralis major and the thoracic 



FIG. 230. Muscles of the chest and front of the arm, with the boundaries of the axilla. 



branches of the acromial thoracic artery. By its posterior surface^ with the 

 ribs, Intercostal muscles, Serratus magnus, the axillary space, and the axillary 

 vessels and brachial plexus of nerves. Its upper border is separated from the 

 clavicle by a triangular interval, broad internally, narrow externally, which is 

 occupied by the costo-coracoid membrane. In this space is the first part of the 

 axillary vessels and nerves. Running parallel to the lower border of the muscle is 

 the long thoracic artery. 



The costo-coracoid membrane should now be removed, when the Subclavius muscle will 

 be seen. 



The Subclavius is a small triangular muscle, placed in the interval between the 

 clavicle and the first rib. It arises by a short, thick tendon from the first rib and 

 its cartilage at their junction, in front of the ^rhomboid ligament; the fleshy fibres 

 proceed obliquely upward and outward, to be inserted into a deep groove on the 

 under surface of the clavicle. 



Relations. By its upfter surface, with the clavicle. By its deep surface it is 

 separated from the first rib by the subclavian vessels and brachial plexus of nerves. 

 Its anterior surface is separated from the Pectoralis major by the costo-coracoid 



