SPAVIN. 303 



evanescent ; also from the characteristic nature of the lameness, the tell- 

 tale wear of the toe of the shoe, and the almost perpetual resting of the 

 limb when standing. 



605. Importance of Spavin dependent on its position. 



The importance of a Spavin depends on its position rather than on its 

 size. 



If it is situated between the bones, and especially if towards the front, 

 there is always great reason to fear that it may, even though small or 

 very small, interfere with the gliding motion of the weight-bearing bones. 

 Further, any such exostosis, however slight, is likely on account of its 

 interfering with that motion to cause further irritation and inflammation 

 in the part, and ultimately ulcerative disease of the articular cartilages 

 and of the bones themselves. 



If, on the other hand, the spavin, even though it be between the bones, 

 is placed far back, it is of less consequence, because there is not much 

 gliding motion in the posterior portion of the hock ; and therefore the 

 exostosis, even though large, may not occasion much inconvenience. 

 Indeed, in many old horses we find that positive union has taken place 

 between the posterior portions of the bones without ever having caused 

 any sensible lameness. 



Spavins on the external surfaces of the bones, and not between them, 

 are less serious. They may or may not interfere with the action accord- 

 ing to their size and position in each particular case. Spavins placed 

 posteriorly and not between the bones, even though large, seldom inter- 

 fere much with the free motion of the hock. 



606. Peculiarities of lameness arising from Spavin. 



In well-developed cases the lameness arising from Spavin is very 

 peculiar and characteristic. It is caused by imperfect flexion of the hock, 

 and in consequence the toe, instead of being properly raised, is dragged 

 along the ground. Towards the end of the month the toe of the shoe 

 is sensibly worn by this abnormal friction. 



In slighter cases some stiffness of the hock and an occasional tripping 

 of the toe may be noticed, and also a sort of vibration in the hock when 

 the toe comes to the ground. These peculiarities will be most observable 

 if the horse is trotted on hard smooth ground. The animal should be 

 especially watched in turning, when a certain degree of flinching or 

 catching up of the leg will be detected. Exercise even for a few minutes 

 greatly diminishes the symptoms ; but when the horse after exercise is 

 allowed to stand till cool, the stiffness will recur, probably in an increased 

 degree. 



In the stable a horse, though only very slightly lame from spavin, will 

 often drop very much, if made to move in his stall to one side, when the 

 weight comes on the diseased leg. In bad cases, in a state of rest, he will 

 usually keep the leg flexed. 



