Muscles of the Thorax. 



161 



215. Muscles of the Thorax. Second and Third 



Layers. 



Second Layer: 



M. subclavius arises from the under surface of the clavicle, and is 

 inserted into the upper border of the first costal cartilage. (Depresses the 

 clavicle and acts as support to the sterno-clavicular articulation.) 



M. pectoralis minor arises by three or four tendinous slips from the 

 outer surface of the second to the fifth ribs, being inserted into the 

 coracoid process of the scapula. ^Depresses the shoulder, elevates the ribs.) 



M. serratus anticus major s. serratus magnus arises by eight or nine 

 fleshy digitations from the outer surface of the eight or nine upper ribs, 

 and is inserted into the inner border of the scapula (see Fig. 223). (The 

 ribs being fixed it draws the scapula forwards; it also helps in supporting 

 weights upon the shoulder.) 



Heitzmann, Atlas. I. 



21 



