144 



COUES, 



in contour with the latter; fleshy fibres take origin from the whole 

 surface of that bone. The muscle narrows and curves a little as it 

 passes clown, directly overlying the shoulder-joint, and in relation 

 anteriorly with the long epicoracoid head of the biceps, to be inserted 

 fleshy into the most prominent part of the pectoral crest of the 

 humerus, above the insertion of the posterior deltoid. When these 

 tw r o muscles act together, they would have the usual effect in elevat- 

 ing, or abducting, the humerus ; acting separately, they have little of 

 this effect, but are respectively extensors and flexors of the bone, 

 with a slight rotating power in opposite directions. 



Independently of the foregoing, there are the usual number of 

 scapulo-humeral muscles ; but owing to the singular shape of the 

 shoulder-blade, position of its faces, and other causes, it becomes 

 somewhat of a question what names are to be applied to them. We 

 describe them accurately, and if mistaken in identification there will 

 be no trouble in rectifying the error. We determine subscapularis, 

 both spinati, no teres minor, and double teres major, making five in 

 all, as usual. 



Supraspinatus. — A slender, straight fascicle, much the smallest of 

 the three that more especially occupy the shoulder-blade. It arises 

 fleshy in the depression between the most prominent point of the 

 scapula and the glenoid — that is, about half-way betwixt these two 

 points, and partly around on the amtero-internal aspect of the bone 

 (owing to the reflexion of the latter), close by the insertion of the 

 omo-hyoid; it passes straight to the joint, which it directly overlies, 

 and is inserted by a short, flat tendon into the anterior tubercle at the 

 head of the bone, just opposite the proximal beginning of the inser- 

 tion of the epicoracoid part of the coraco-brachialis. It rotates the 

 humerus outward, as usual directly opposing the subscapularis. 



Infraspinatus (and teres minor? or the latter wanting?). — Largest 

 of the three. Occupies, and arises fleshy from, the whole of the 

 scapular plate beldw the spinous elevation, that is, between the last 

 named and the origin of the scapular head of the triceps ; narrowly 

 fan-shaped and slightly curving, to be inserted, partly fleshy and 

 partly tendinous (tendon superior and muscular part infero-external), 

 into the posterior aspect of upper part of pectoral crest, just below 

 insertion of the preceding, which it powerfully aids in rotating the 

 humerus outward. 



Subscapularis. — This is in what would be for most animals the 

 usual position of "infraspinatus," and might be taken for the latter, 

 were it not for its widely distant insertion into the other side of the 

 head of the humerus. A rather small subterete fascicle, arising 

 fleshy from that part of the scapula which lies between the glenoid 

 and head of the triceps extensor brachii ; crossing to the shoulder- 



