MUSCLES OF THE TliUNK. 



295 



nerves of the inner aspect of the arm, throu^^h the medium of the sub-brachial 

 aponeurosis of the pauuiculus and a considerable (juantity of connective tissue. 

 Its upper border adheres in an intimate manner to the last-named muscle, and is 

 bordered by the spur (external thoracic) vein. The large vascular trunks which 

 leave the chest to reach the anterior limb, pass above its anterior extremity, in 

 crossing its direction. 



Action.— It pulls the whole limb backwards, in pressing on the angle of the 

 shoulder. 



B. Sterno-peescapularis.— (The pectoraUs parrus of Percivall and Bour- 

 gelat.)— Form— Situation— Direction.— A long prismatic muscle, contracted at its 

 two extremities, situated in front of the preceding, arising from the sternum, 

 directed forwards and outwards towards the scapulo-humeral angle, and after- 

 wards reflected upwards and backwards on the anterior border of the shoulder, 

 which it follows to near the cervical angle of the scapula. 



Structure and Attachments.— It is formed of very large fleshy fasciculi, 



