228. THE HORSE. 



We beg-in with the fore extremity, and with its upper part the shoulder 

 It is seen at G, page 63. 



THE SHOULDER. 



Tiie scapula, or shoulder-blade, situated forward on the side of the 

 chest, is a bone of a somewhat triangular shape, with its apex or point 

 downward, and its base or broad part upward. The point lies between 

 the first and second ribs ; the hinder part of the base reaches as far back 

 as the seventh rib; it therefore extends obliquely along the chest. It is 

 divided, externally, into two unequal portions by a ridge or spine running 

 through almost the whole of its extent, and designed, as we shall pre- 

 sently show, for the attachment of important muscles. The broad or upper 

 part having- no muscles of any consequence attached to it, is terminated by 

 cartilage. 



We have stated that the muscles of the hinder legs are principally con- 

 cerned in the motion of the horse. They impel the machine forward, and 

 the main uses of the fore extremities are to lift the fore part of the horse from 

 the ground, that it may be thus impelled to throw forward the legs as 

 far as possible that they receive this weight at due distance, and to sup- 

 port the ibrce and shock of that weight when it reaches the ground. We 

 will inquire as we proceed how far one or all of these objects are accom- 

 plished. 



The shoulder-blade is united to the chest by muscle alone. There is 

 a large muscle, with very remarkable tendinous fibres, and of immense 

 strength (the serratus major ^ greater saw-shaped muscle), attached to the 

 chest, and to the extensive smooth internal surface of the shoulder-blade, 

 and by which, assisted, or rather strengthened, by the muscles of the 

 breast, the weight of the body is supported, and the shock of the widest 

 leap, or the most rapid motion, sustained. Had there been a bony union 

 between the shoulder and the body, the vital parts contained in the chest 

 could not have endured the dreadful shock which they would occasionally 

 have experienced; nor could any bone have long remained whole if exposed 

 to such violence. Tlie muscles within the shoulder-blade act as powerful 

 and safe springs. They yield, as far as necessary, to the force impressed 

 upon them ; by their gradual yielding they destroy the violence of the 

 shock, and then, by their elastic power, immediately regain their former 

 situation. 



SPRAIN OP THE SHOULDER. 



In some violent and unexpected shock these muscles are occasionally in- 

 jured. Although we do not believe that, in one case in twenty, the farrier 

 is right when he talks of his shoulder-lameness, yet it cannot be denied, 

 that the muscles of the shoulder are occasionally sprained. This is cfliccted 

 oftener by a slip or side-fall, than by fair, although violent exertion. It is 

 of considerable importance to be able to distinguish this shoulder-lameness 

 from injuries of other parts of the fore extremity. We shall look in vain 

 for much tenderness, or heat or swelling : it is a sprain of muscles deeply 

 seated, and where these symptoms of injury cannot possibly exist. If, on 

 standing before the horse, and looking at the size of the two shoulders, or 

 rather their points, one should appear evidently larger than the other, we 

 must not consider this as indicative of sprain of the muscles of the 

 shoulder. It probably arises from bruise of the point of the shoulder, 

 which a slight examination will determine ; or the whole of the limb, this 



