238 LAMENESS OF THE HORSE 



to cunean tenotomy are primarily due to affection of the cunean 

 bursa. 



Symptomatology. — Where a visible exostosis exists, the pres- 

 ence of spavin is easily detected, yet exostoses that extend over 

 large areas may constitute cause for serious trouble and still be 

 difficult of detection. By observing the internal surface of the 

 hock from various suitable angles, such as from between the 

 forelegs or directly behind the subject, one may note the pres- 

 ence of any ordinary exostosis. 



The position assumed by the spavined horse is often charac- 

 teristic. More or less knuckling is usually present (Liautard, 

 McDonald) . There is abduction of the stifle in some cases, or the 

 toe may be worn in unshod horses so that it presents a straight 

 line at the surface. This is manifested to a great degree in some 

 animals and in others the foot is not dragged and there is no 

 wearing of the hoof at the toe. 



Spavin lameness is so distinctive that one trained and experi- 

 enced in the examination of horses that are spavined, should 

 correctly diagnose the condition in practically every instance 

 without recourse to other means than noting the peculiar char- 

 acter of the gait of the subject. Lameness develops gradually 

 in the majority of instances, and an important feature in spavin 

 lameness is that it disappears after the subject has gone a little 

 way, to return again as soon as the animal has rested for a 

 variable length of time— from a half hour to several hours. This 

 "warming out" is marked during the incipient stage, but less 

 pronounced in most chronic cases. A complete disappearance 

 of lameness is observed in some instances, while in others only 

 partial subsidence is evident. Because of the fact that pain is 

 occasioned both during weight bearing and while the leg is being 

 flexed and advanced, there is manifested the characteristic mixed 

 lameness and exaggerated hip action which typifies spavin. By 

 throwing the hips upward with the sound member it is possible 

 to advance the affected leg with less flexion, hence less pain is 

 experienced in this manner of locomotion. When made to step 

 aside in the stall, a spavined horse will flex the affected member 

 abruptly and when weight is taken on the diseased leg, symp- 



