=Coraco-brachialis.=--In man this muscle, which occupies the superior half, or third, of the internal surface of the humerus, is visible only when the arm is abducted, and then especially when it approaches the vertical position; indeed, it is only in this attitude that the region which it occupies is accessible to view. But an analogous attitude not being possible in domestic animals, in which the arm is fixed along the corresponding parts of the trunk, the result is that the coraco-brachialis is always covered, and that, consequently, it presents nothing of interest from our point of view. We speak of it, then, merely in order to complete the series of the muscles of the anterior surface of the arm, among which we rank it, in spite of the fact that in veterinary anatomy it is described as a muscle of the shoulder. It arises above from the coracoid process, and thence passes downwards towards the internal surface of the humerus into which it is inserted, more or less high up, according to the species. The coraco-brachialis is an adductor of the arm. Posterior Region =Triceps Cubiti= (Fig. 68, 23, 24; Fig. 69, 20, 21; Fig. 70, 28, 29; Fig. 72, 13, 14, 15, 16).--This muscle, which is voluminous in the quadrupeds with which we are here concerned, fits more or less completely the angular space between the scapula and the humerus. Its bulk forms a thick prominence, which surmounts the elbow and the forearm. We should say, with regard to this mass, that if the deltoid does not constitute in quadrupeds a prominence sufficient to remind one of that which this muscle produces in man, the triceps, in producing an analogous elevation, seems to replace in the general form of the body the relief which the deltoid is incapable of producing. The triceps is divided into three portions, which, as in man, have the names middle, or long head; external and internal heads. But that which renders the nomenclature a little complicated is that veterinary anatomists have given other names to these three parts: that of _great extensor of the forearm_ (caput magnum) to the long head; _the short extensor of the forearm_ (caput parvum) to the external head; and of _medium extensor of the forearm_ (caput medium) to the internal.[24] [24] Other names given by certain authors to the parts of this muscle which we have just enumerated still further complicate this nomenclature. The long head is further designated by them under the names of the _long_ or _great anconeus_; the _external head_ under those of _external anconeus_, or _lateral_ or _short anconeus_; whilst the internal head becomes the _internal anconeus_, or _median_. It is more especially the long portion and the external head which, being visible on the external surface of the arm, contribute to the external form.