SPECIAL INJURIES OF BONES. 345 



These usually begin as inflammation of the membrane 

 covering the bones, and at such points as give attachment to 

 ligaments — namely, the lateral aspects of the lower or small 

 pastern bone, and of the lower end of the upper or large bone. 

 There is a circumscribed, tender, and somewhat elastic swelling, 

 with more or less soft, doughy engorgement of the investing 

 soft parts, and in course of time the exuded matter, at first 

 soft, becomes hard and bony. The process in the early 

 stages often appears to consist in the dragging of the periosteum 

 and vessels from the surface and the development of bone be- 

 neath. But as the disease advances the whole surface of one 

 or both bones may become involved, leading to a general de- 

 position of new bony matter, extending, it may be, over the 

 joint between the two pastern bones, or between the lower 

 pastern and the bone ot the foot, and abolishing all movement. 

 Ringbones may also take origin in partial fractures, in con- 

 cussion, in rheumatoid disease, and in faults of nutrition, in 

 which the earthy salts are largely passed with the urine. 



Symptoms. — Lameness may be almost altogether absent, or 

 it may be extreme in such cases as are attended by active in- 

 flammation of the bone or joint, or when the joint has become 

 fixed by bony deposit. The heel may be first brought to the 

 ground, or, in the hind foot, the fetlock may knuckle over and 

 the toe strikes fir:.t. The lameness is worst on hard ground 

 and usually increases with exercise. Swelling may be scarcely 

 perceptible and confined to the inner or outer side oi one 

 pastern bone, or it may be an extreme enlargement of the whole 

 pastern region. It may be hard throughout in old cases, or softer 

 and slightly elastic at points where active disease is still going on. 

 Forcibly bending oi the pastern causes much pain, as also pres- 

 sure on the swelling, and especially on the softer and more recent 

 deposits. 



Treatjnent. — Rest, second the indications of nature in order 

 to secure an easy position, using a high-heeled shoe when the 



