DISEASES OF THE HORSE. 413 



action set up in the periosteum and bone tissue proper of the large and 

 small pastern bones. (Plate XXXIl, fig. 1.) 



Causes. — Injuries, such as blows, sprains, overwork in young, unde- 

 veloped animals, fast work on hard roads, jumping, etc., are among 

 the principal exciting causes of ringbones. Horses most disposed to 

 this disease are those with short upright pasterns, for the reason that 

 the shock of locomotion is but imperfectly dissipated in the fore legs 

 of these animals. Improper shoeing, such as the use of high calks, 

 a too great shortening of the toe and correspondingly high heels, 

 predispose to this disease b}^ increasing the concussion to the feet. 



Sym/ptoins. — The first symptom of an activel}^ developed ringbone 

 is the appearance of a lameness more or less acute. If the bony tumor 

 forms on the side or u.pper parts of the large pastern, its growth is 

 generally unattended with acute inflammatory action, and conse- 

 quently produces no lameness or evident fever. These are called 

 " false" ringbones. But when the tumors form on the whole circum- 

 ference of the ankle, or simply in front under the extensor tendon, or 

 behind under the flexor tendons, or if they involve the joints between 

 the two pastern bones, or between the small pastern and the coffin- 

 bone, the lameness is always severe. These constitute the true ring- 

 bone. Besides lameness the ankle of the affected limb presents more 

 or less heat, and in many instances a rather firm, though limited, 

 swelling of the deeper tissues over the seat of the inflammatory proc- 

 ess. The lameness of ringbone is characteristic, in that the heel is 

 first placed on the ground when the disease is in a fore legj and the 

 ankle is kept as rigid as possible. In the hind leg, however, the toe 

 strikes the ground first, when the ring})one is high on the ankle, just 

 as in health, but the ankle is maintained in a rigid position. If the 

 bony growth is under the front tendon of the hind leg, or if it 

 involves the coffin joint, the heel is brought to the ground first. In 

 the early stages of the disease it is not always easy tcr diagnose ring- 

 bone, but when the deposits have reached some size they can be felt 

 and seen as well. 



The importance of a ringbone depends on its seat and often on its 

 size. If it interferes with the joints or with the tendons it may cause 

 an incurable lameness, even though small. If it is on the sides of the 

 large pastern, the lameness generally disappears as soon as the tumor 

 has reached its growth and the inflammation subsides. Even where 

 the pastern joint is involved, if complete anchylosis results, the patient 

 may recover from the lameness-with simph^ an imperfect action of the 

 foot remaining, due to the stiff joint. 



Treatment. — Before the bony growth has commenced the inflam- 

 matory process may be cut short by the use of cold baths and wet 

 bandages, followed by one or more blisters. If the bony deposits 

 have begun the firing iron should always be used. Even where the 



