MUSCLES SITUATED ON THE SCAPULA. 361 



spine of the scapula outwards, forwards, and downwards ; and 

 from the acromion, straight downwards ; and is composed of a 

 number of fasciculi, which form a strong fleshy muscle that 

 covers the anterior part of the joint of the os humeri. 



Inserted, tendinous, into a rough protuberance in the outer 

 side of the os humeri, near its middle, where the fibres of this 

 muscle intermix with some part of the brachialis externus. 



Use. To pull the arm directly outwards and upwards, and 

 a little forwards or backwards, according to the different direc- 

 tions of its fibres. 



2. Cor aco- Brachialis, 



Arises, tendinous and fleshy, from the forepart of the coracoid 

 process of the scapula; adhering in its descent, to the short 

 head of the biceps. 



Inserted, tendinous and fleshy, about the middle of the 

 internal part of the os humeri, near the origin of the third 

 head of the triceps, called brachialis externus, where it sends 

 down a thin tendinous expansion to the internal condyle of the 

 os humeri. 



Use. To raise the arm upwards and forwards. 



N. B. There passes a nerve through this muscle, called 

 musculo cutaneus. 



The one beneath the scapula is, 



Suhscapularis, 



Arises, fleshy, from all the base of the scapula, internally, 

 and from its superior and inferior costJE, being composed of a 

 number of tendinous and fleshy fasciculi, which make prints 

 on the bone ; they all join together, fill up the hollow of the 

 scapula, and pass over the joint, adhering to the capsular 

 ligament. 



Inserted, tendinous, into the upper part of the internal protu- 

 berance at the head of the os humeri. 



Use. To roll the humerus inwards, and to draw it to the side 

 of the body ; and to prevent the capsular ligament from being 

 pinched. 



31 



