334 THE ARM. 



from the shoulder and the bone of the aim take a direction much nearer to a 

 perpendicular line in the long than in the short elbow, and therefore act with 

 proportionably greater advantage ; and if this advantage from the direction in 

 which the power is applied to that which we gain from the increased length of 

 the bone is considered, it will be plain that the addition of one- third to the 

 length or projection of the elbow would be attended by a saving of one-half in 

 the expenditure of muscular power. There is, however, a limit to this. In 

 proportion as the elbow is lengthened, it must move over a greater space in order 

 to give the requisite extension to the limb ; and consequently the muscles which 

 act upon it must be lengthened, otherwise, although the action might be easy 

 it would be confined. There must be harmony of proportion in the different 

 parts of the limb, but a deep elbow, within a certain range, is always connected 

 with increased power of action. 



The elbow is sometimes fractured. If the animal is placed in the hands of a 

 skilful veterinarian, although the chances of cure are certainly against the horse, 

 yet the owner needs not to despair. The treatment of fracture of the elbow- 

 joint will be considered in its proper place. 



Enlargements sometimes appear about the elbow, either the consequence of 

 a violent blow, or from the calkins of the shoes injuring this part when the 

 horse sleeps with his legs doubled under him. If a set on i3 passed through the 

 tumour, it will sometimes rapidly diminish, and even disappear ; but if it is of 

 considerable magnitude, the skin should be opened along the middle of the 

 swelling, and the tumour dissected out. 



The elbow-joint is sometimes punctured, either accidentally, or through the 

 brutality of the groom or carter. The swelling is often rapid and extensive, 

 and fatal inflammation may ensue. Rest, and the closure of the wound, are the 

 most important considerations. 



There are other muscles of the fore-arm employed in extending the limb. 

 At x, page 330, is the principal one, called the extensor metacarpi. It is 

 attached superiorly to the outer and fore parts of the external condyle of the 

 humerus, and also to the capsular ligament, and inferiorly to the antero-superior 

 part of the great metacarpal bone. Its superior attachments are principally 

 fleshy, with a few tendinous fibres interposed. These diminish towards the 

 centre, but a little lower down is a tendon, round at its origin, but gradually 

 growing flat and expanding in breadth towards its termination. Its office is to 

 extend the leg. 



The next muscle in situation and importance is seen at w, and called the 

 extensor pedis. It rises from the fore part of the external condyle of the 

 humerus, and pursues its course down the leg, and expanding after it has passed 

 the fetlock, it serves the purpose of a capsular ligament, covering and adhering 

 to the pastern joints. Its office is to extend the foot and pasterns, and, at the 

 same time, to assist in the extension of the knee. 



At u, page 330, is the tendon of another extensor muscle, and at s a curious 

 oblique one, passing over the tendon of x, confining it in its situation, and like- 

 wise itself assisting in extending or straightening the leg. 



The muscles employed in bending the leg are both numerous and powerful. 

 Two of the superficial ones are given in the cut, page 331. The first is at t 

 page 330 ; it is also seen at b, page 330. It is called the flexor medius meta- 

 carpi, because its office is to bend the leg. The other is seen at v, page 330. 

 It is called the flexor metacarpi externus, and is also designed to flex the leg. 



The internal flexor is seen at e. Its office is also to bend the leg. 



A portion of one of the most powerful of the flexor muscles, and powerful 

 indeed they must be, is delineated at c, p. 330. It is the flexor brachii. It 

 rises from the extremity of the ridge of the shoulder-blade in the form of a 

 large and round tendon, which runs between two prominences in the upper 



