218 MYOLOGY. 



CORACO-HUMERALIS. 



Omo-brachialis. 

 (Fig. 79. c.) 



Situated on the inner side of the humerus, this muscle is ten- 

 dinous, long, and fusiform, its fibres passing obliquely downwards. 



Attachments. — From the beak of the coracoid process of the 

 scapula. Passing between the subscapularis and the antea- 

 spinatus, the tendon is succeeded by two fleshy bellies, a super- 

 ficial and a deep one. The latter, thin and short, is inserted to 

 the shaft of the humerus just above its internal tuberosity ; the 

 former, by far the larger, is inserted to a rough surface on the 

 same bone, lower down, and more anteriorly. 



Relation. — Anteriorly with the flexor brachii j superiorly with 

 the antea-spinatus and subscapularis ; internally with the pector- 

 alis magnus; posteriorly with the latissimus dorsi and terea 

 internus, whose tendons pass between its two bellies. 



Action. — To extend, adduct, and rotate the arm inwards. 



HUMERALIS OBLIQUUS. 



(Humero-radialis — Brachialis Anticus.) 



(Fig. 80, d.) 



OccupyiDg the musculo-spiral groove, it is flat, oblong, wide 

 superiorly, and almost entirely fleshy; it covers successively 

 portions of the posterior, external, and anterior surfaces of the 

 humerus, terminating on the inner aspect of the radius. 



Origin. — From the postero-superior part of the shaft of the 

 humerus, just below the articular head, winding round the bone 

 under the external tuberosity. 



Insertion. — To a ridge on the inner part of the head of the 

 radius, after passing through a transverse groove just below, and 

 within the insertion of the flexor brachii ; also to the ulna, passing 

 imder the internal-lateral ligament of the joint, and blending with 

 the arciform ligament. 



Relation. — Externally with the caput magnum and caput 

 medium ; internally with the humerus ; anteriorly with the flexor 

 brachii. 



Action. — Solely to flex the elbow joint. 



