256 DISEASES OF BONE. 



nection with the small bones of the hock, which are above the 

 cannon bone and splint bones. 



1 believe that a splint, having the appearance of a low spavin, 

 rarely occurs on the head of the cannon bone without involving 

 the cuneiform medium also ; although union of these bones f re- 

 (|uently takes place without the action of the animal being affected 

 in any perceptible manner; as there is very little motion in that 

 joint. The cuneiform medium, as the seat of spavin, has a natu- 

 rally well-marked bony ridge on its surface, which gives it the 

 appearance of having a small sjDlint (Fig. 129). 



The more to the front of the hock the bony deposit is situated, 

 the greater danger is there of its giving rise to lameness ; because 

 in that case it is more apt to interfere with the action of the 

 joint, than if it was at the side. 



The lameness of spavin in horses six years old and under is 

 usually curable ; but not that of old horses (see remarks on occult 

 spavin). 



Coarse hocks need not be viewed with suspicion if both be exactly 

 similar and if the action is good. Faulty action from spavin is 

 generally indicated by undue wear at the toe (Fig. 1, p. 6). The 

 term, " coarse " hock, is applied to those hocks in which the 

 head of the cannon bone and the prominences on the bones 

 above it are largely developed. In them, the cuneiform 

 bones are large, and consequently this shape is the one 

 which is best adapted for diminishing the ill effects of con- 

 cussion and compression. Although the hock shown in Fig. 96 

 and its fellow were too coarse to be i>assed by most veterinary 

 surgeons ; their owner, a well-bred Irish mare, had perfect action in 

 them, and was a very clever hunter and remarkably " big " jumper. 

 This furnished a good example of the not uncommon case of the 

 existence of spavin being no detriment to a horse's action. Ex- 

 perience teaches us that work develops bone as well as muscle ; 

 consequently hunters, as a rule, have coarser hocks than hacks and 

 light harness horses. 



If an " aged " horse has coarse hocks and goes sound, especially, 

 if he has good action, there is little probability of his becoming 

 lame in them. Young horses often have enlarged hocks which fine 

 down as they grow older. 



OCCULT SPAVIN is the term used to signify that condition of 

 the hock in which no external evidence of disease can be observed ; 

 although the lameness due to pain in the part may be of a most 

 inveterate form. We have here ulceration of the surfaces 

 of the bones which form the gliding joints without bone 

 being deposited between or about them. In health, the dif- 



