lameness: its causes and treatment. 319 



A minute I'xaiiiinalion of the lu)clv may tlieu reveal the existence of 

 •A bony enlarji:ement whicli may be detected just at tiie jjuutioii of the 

 I'.ock and the eainion bone, on the inside and a littk' in front, and 

 tan«;ible both to si^ht an«l touch. This enhir«i^ement, or bone spavin, 

 ^rows rapidly and persistently and soon aecjuires dimensions Mhich 

 lenders it impossible to doubt any longer its existence or its nature. 

 Once established, its development continues imder conditions of pro«:j- 

 ress similar to those to which we have befoi'e alhuied in speakinjj of 

 other like afl'ections. The arjj:ument advanced by some that because 

 these bony deposits are frecjuently found on both hocks they are not 

 spavins is fallacious. If they are discovered on both hocks, it proves 

 merely that they are not confined to a single joint. 



The characteristic lameness of bone spavin, as it aHects the motion 

 of the hock joint, presents two aspects. In one class of cases it is 

 most pronounced when the horse is cool, in the other when he is at 

 work. The first is characterized l)y the fact that when the animal 

 travels the toe first touches the ground, and the heel descends more 

 slowly, the motion of flexion at the hock taking place stiffly, and 

 accompanied with a dropinng of the hip on the opposite side. In the 

 other case the peculiarity is that the lameness increases as the horse 

 travels; that when he stops he seeks to favor the lame leg, and when 

 he resumes his work soon after he steps much on his toe. as in the 

 first variety. 



As with sidebones. though for a somewhat different reason, the 

 dimensions of the si)avin and the degree of the lameness do not seem 

 to bear any determinate relation, the most pronounced symptoms at 

 times accompanying a vevy diminutive growth. The distinction 

 between the two varieties of cool and waiiu. however, nuiy easily lie 

 determined by remembering the fact that in most cases the first, or 

 cool, is due to a simple exostosis, wliile the second is generally con- 

 nected with disease of the articulation, such as ulceration of the 

 articular surface — a condition which, as we proceed further, will 

 receive our attention when we reach the sui)ject of stringhalt. 



An excellent te^t for spavin lameness, which may be readily 

 applied, consists in lifting tiie affected leg from the giound for one 

 or two minutes and holding the foot high so as to flex all the joints. 

 An assistant, with the haltei- stra|) in his hand, (piickly stai'ts the 

 animal off in a trot, when, if the hock joint is affected, the lameness 

 will be so greatly intensified as to lead readily to a diagnosis. 



Pi'og7Wsix. — Having thus fully con-idered the history of l>one 

 spavin, we are prepared to give due weight to the reasons that cxi.st 

 for the adverse piognosis which we must usually fi^el compelled to 

 pronounce when encountering it in practice, as well as to realize the 

 importance of early di.scovery. It is but seldom, however, that the 

 necessary advantage of this early knowledge can be obtained, and 



