136 MUSCULAR SYSTEiM. 



Structure. — Mostly covered by a dense aponeurosis. Below, 

 it is entirely aponeurotic, and spreads over the infero-external 

 part of the shoulder. 



Action. — It will co-operate with the postea-spinatus. 



4.— ANTERIOR HUMERAL REGION. 



COR A CO -HUM ERA LIS. 



Situation. — Infero-internal part of the shoulder. 



Form. — Pyramidal: base turned downwards; flattened from 

 without inwards. 



Attachment. — Superiorly, to the coracoid process of the sca- 

 pula : inferiorly, to the middle third of the antero-internal part of 

 the body of the humerus. 



Relations. — Externally, with the pectoralis transversus and 

 the ribs, also with the humeral blood-vessels and nerves ; inter- 

 nally, with the body of the humerus; antero-inferiorly, with the 

 flexor brachii ; postero-superiorly, with the teres major and 

 latissimus dorsi ; superiorly, its tendon runs between the sub- 

 Bcapularis and antea-spinatus. 



Structure. — A flattened tendon, about three inchesin length, 

 forms its superior attachment ; from which extends a fleshy belly, 

 partly aponeurotic upon its surfaces, and intersected in places 

 through its substance by tendinous divisions. Its lower attach- 

 ment is principally (but not entirely) fleshy. 



Action. — To extend the shoulder joint; and to incline the 

 humerus inwards. 



FLEXOR BRACHII. — Coraco-radioUs. 



Situation. — Antero-inferior part of the shoulder. 



Form,. — Cylindroid : flattened, superiorly, from before back- 

 wards; inferiorly, from side to side. 



Attachment. — Superiorly, to the coracoid process of the sca- 

 pula ; inferiorly, to the inner parts of the head and neck of the 

 radius, to the capsular Hgament of the elbow joint, and to the 

 brachial faschia. 



Relations. — Anteriorly, with the faschia and skin ; posteriorly, 

 with the elbow joint and the humerus; externally, with the pec- 

 toralis transversus ; internally, with the coraco-humeralis. Its 

 tendon, superiorly, issues from the space between the terminating 

 portions of the antea-spinatus ; and the superficial brachial vein 

 ascends to the outer side of it. 



Structure. — The muscle is fixed to the scapula by a broad, 

 short, thick tendon, which runs within the groove between the 

 tubercles of the humerus ; its posterior surface (which much re- 

 sembles cartilage in its texture) being hollowed and adapted to a 



