Common Diseases of the Horse 179 



serious, on account of the unresisting nature of the structures 

 involved. Much pain is occasioned, while relief is most difficult 

 to effect. In the young animal, considerable differences in the size 

 of the bones of the limb are frequently met with which may be 

 mistaken for ringbones. The pasterns will be found not to be 

 pairs, and one side may be larger than the other. These differ- 

 ences occur on the roughened surfaces of the bone, where certain 

 ligaments are inserted, and are really small deposits resulting from 

 the deposition of lime salts; as maturity advances they are absorbed, 

 and the bone eventually " fines " down to its normal condition. 



The lameness arising from ringbone, if in the fore limb, and 

 particularly on the front of the joint, causes the horse to go on his 

 heels, as though affected with inflammation of the feet; if on the 

 hind limb, he goes on his toe. The exciting causes of the disease 

 are no doubt concussion and any uneven distribution of weight 

 upon the terminal bones of the limb. 



Thus a horse with badly-shaped pasterns — either too long or 

 too short — although he will be all right as long as he is in the 

 country or worked on soft land, will soon develop ringbones when 

 brought on to the sett-paved town. Bad shoeing must also be 

 reckoned as a factor, as by paring the hoof undue weight is thrown 

 upon the limb, eventually causing inflammation of either the mem- 

 branes of the joint — those which secrete the oil — or the bone and 

 the covering of the bone, any of which may be responsible for the 

 ultimate bony deposit. 



Treatment, — Treatment consists either in trying to fix the joint, 

 which may be done by firing and blistering, or removing all feeling 

 from the pasterns by severing the nerve just above the fetlock. 

 The latter is a somewhat risky operation in heavy horses, as after 

 the operation there is a tendency to degeneration of the foot, in 

 which case slaughter is necessary. Appropriate shoeing, such as 

 a plain or rocker round shoe, particularly if the case is on soft 

 ground, often gives relief. 



Sidebone 



In describing this disease, it is necessary to consider very briefly 

 the construction of the foot. 



The terminal bone of the limb, known as the coffin bone, is 

 contained entirely within the horny box of the hoof, and corre- 

 sponds to the shape of the latter. Besides this bone there are 

 two others. One is attached to the supero-posterior border, and 

 is the navicular bone. Above this, partly within and partly 

 without the hoof, and articulating at its upper extremity with 



