250 THE HORSE. 



m Tendon of the perforating' flexor inserted into the coffin-bone, after having^ paosed 



over the navicular-bone. 



n Seat of the navicular-joint lameness. 



o Inner or sensible frog, 



p Cleft of the horny frog' 



q A ligament uniting the navicular-bone to the smaller pastern, 



r A ligament uniting the navicular-bone to the coffin-bone. 



s Sensible sole between the coffin-bone and the horny sole. 



t Horny sole. 



u Crust or wall of the foot. 



T Sensible laminie to which the crust is attached. 



IT Coronary ring of the crust. 



X The covering of the coronary ligament from which the crust is secreted. 



z Place of bleeding at the toe. 



It will be easy to perceive, from this description of the situation of tfie 

 (suspensory ligament, why splints placed backward on the leg are more 

 likely to produce lameness than those which are found on the side of the 

 leg. They may interfere with the motion of this ligament, or, if they are 

 large, may bruise and wound it. 



The principal action of these ligaments is with the sessamoid-bones, 

 which they seem to suspend in their places, and they are therefore called the 

 suspensory ligaments. The pasterns (see cut, p. 249) are united to the 

 shank in an oblique direction, differing in degree in the different breeds of 

 horses, and in each adapted to the purpose for which that breed was 

 designed. The weight falls upon the pastern in the direction of the shank- 

 bone ;* and the pastern being set on obliquely, a portion of the weight must 

 l>e communicated to the sessamoids. Much jar is saved by the yielding of 

 the pasterqs, in consequence of their oblique direction; and the concussion 

 which would be produced by that portion of weight which falls on the ses- 

 samoid-bones, is completely destroyed ; for there is no bone underneath to 

 receive it. They are suspended by this ligament ; an elastic ligament, 

 which gradually yields to, and is lengthened by, the force impressed upon 

 it, and in this gradual yielding and lengthening, all painful or dangerous 

 concussion is rendered impossible. The ease and comfort of the animal of 

 course greatly depends upon its perfect action. 



If the ligament lengthens, the sessamoid-bones must descend when the 

 weight is thrown on them, and it would appear that they do so. If the 

 thorough-bred horse, with his long pasterns, is carefully observed as he 

 stands, the tuft at the fetlock will be some inches from the turf; but when 

 he is in rapid motion, and the weight is thrown violently on this joint, the 

 tuft descends, and sweeps the \ery ground. This, however, is the combined 

 action of the fetlock and pastern -joints, and the sessamoid-bones. The 

 sessamoids do not actually descend, but they revolve, and partly turn over. 

 The strong ligament by which they are attached to the pastern-bone acts as 

 a hinge, and the projecting part of the bone to which the suspensory liga- 

 ment is united, turns round with the pressure of the weight; and so that 

 fmrt of the bone becomes lower. How is it raised again ? This ligament, 

 strangely constructed as a ligament, is elastic. It yields to the force im- 

 pressed upon it, and lengthens; but as soon as the foot is lifted from the 

 ground, and the weight no longer presses, and the force is removed, its 

 elastic power is exerled, and it regains its former dimensions, and the ses- 

 samoid-bone springs back into its place, and by that forcible return assist* 

 in raising the limb.* 



* Mr. Percivall very clearly describes this : " Furthermore, it seems to us that theaa 

 elastic paru assist in the elevation of the feet from the ground in those pitea io whiefa 



