288 PRINCIPLES OF VETERINARY SCIENCE 



joint and progresses so far that the bones of the articulation 

 become firmly, welded together, the joint is said to be ankylosed 

 and a stiff, immovable articulation results. A dull, continuous 

 pain is always present in ostitis. The most satisfactory treat- 

 ment is the counterirritant applied either as a blister or the 

 actual cautery. 



Osteomyelitis is inflammation of the bone-marrow. It is a 

 serious disease, but fortunately is relatively rare. Suffice it to 

 say that infectious forms of osteomyelitis are usually incurable. 



From a practical point of view there are three forms of inflam- 

 mation of bone which deserve especial mention. They are bone 

 spavin, ring-bone, and splints. Usually they all cause an exosto- 

 sis to appear at the seat of the inflammation. Each reduces the 

 value of the horse for both work and breeding purposes, but not 

 in the same degree. When considered in order of importance 

 they should be ranked as mentioned above, for spavin is a more 

 serious disease than ring-bone, which, in its turn, incapacitates 

 the horse to a much greater extent than does a splint. 



BONE SPAVIN 



Bone spavin is the term applied to the exostosis that occurs 

 on the inner side and in front of the hock-joint (Fig. 73). There 

 are three kinds or forms of spavin — viz., (1) high or "true spavin," 

 which is the most serious; (2) low or "jack spavin," which does 

 not interfere to such an extent with the joint; (3) occult or "blind 

 spavin," which involves the joint surfaces, presents no enlarge- 

 ment, but is accompanied by marked lameness. 



Causes. — Bone spavin may be caused by any object that pro- 

 duces inflammation — for example, faulty conformation; mechan- 

 ical injuries to the hock, either from blows or kicks or from too 

 rapid and hard' work on paved streets; excessive strain upon the 

 hock-joint from improper shoeing. 



Symptoms. — Lameness is the first symptom noticeable. The 

 horse avoids moving the joint and develops a characteristic 

 "spavined gait," in which a slight hitch is observed in the hip on 

 the affected side and a decided dropping of the opposite hip. 

 This is most pronounced when the horse first staits, and results 

 from throwing the weight of his body upon the sound leg. When 

 diiven a short distance he "warms out" of the lameness. After 



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