148 THE CAT. [CHAP. v. 



These two parts have a common insertion into the lower third of 

 the flat deltoidal surface on the outer side of the humerus external 

 to the bicipital groove. 



The third part arises from the hinder side of the clavicle and 

 fuses with the adjacent part of the cephalo-humeral. 



The levator claviculw is a muscle which takes origin from the 

 transverse process of the atlas. 



It is inserted into the end of the metacromion (between the first 

 and second parts of the deltoid), being overlapped by the cephalo- 

 humeral and, quite anteriorly, by the sterno-mastoid. 



The supra-spinatus forms a very large muscular mass, which 

 projects much beyond the anterior margin of the scapula. It 

 arises from, and occupies the supra-spinous fossa of the scapula, with 

 anterior side of the spine and acromion. It is inserted into the 

 upper margin of the great tuberosity. 



The infra-spinatus occupies the infra-spinous fossa of the scapula 

 (arising from its whole surface, including the hinder side of the 

 scapular spine, acromion and metacromion), and is inserted into the 

 concavity on the posterior part of the outer side of the great 

 tuberosity. 



The teres minor arises from the lower half of the axillary margin 

 of the scapula, and is inserted into the hinder margin of the great 

 tuberosity, below the insertion of the infra-spinatus. 



The teres major is a much larger muscle which takes origin from 

 the posterior angle of the scapula and the upper third of its axillary 

 margin. It is inserted below the lesser tuberosity by a strong 

 tendon common to it and to the latissimus dorsi. 



The subscapularis occupies the whole inner surface of the scapula. 

 Its fibres converge from this extensor origin and are inserted into 

 the lesser tuberosity and capsular ligament of the head of the 

 humerus. 



The supra-spinatus, infra-spinatus and teres minor rotate the limb 

 outwards, or tend to draw it forwards and raise it. 



The subscapularis and teres major rotate the limb inwards, and 

 tend to draw it backwards. 



The coraco-brachialis is a very short muscle which arises by a 

 delicate tendon from the coracoid process of the scapula, and is 

 inserted into the inner side of the humerus just below the insertion 

 of the subscapularis (and mainly above that of the teres major,) 

 between the biceps and the fourth head of the triceps (Fig. 81, Cb). 



The biceps arises by a tendon which takes origin from the upper 

 margin of the glenoid cavity of the scapula. Passing down it is 

 inserted by a tendon into the tubercle of the radius (B). 



The bmchiaUs anticm is a muscle placed on the outer side of the 

 front aspect of the humerus, taking origin from the surface of that bone 

 as high up as just below the insertion of the teres minor (Fig. 80, Ba). 



It passes down between the second part of the pectoralis major, 

 the triceps and the supinator longus, and is inserted into the coronoid 

 process of the ulna, and into the ulna on the inner side of that 



