This section is from the book "The Farmers Ready Reference Or Hand Book Of Diseases Of Horses And Cattle", by S. C. Orr. . Also available from Amazon: The Farmer's Ready Reference;.
A splint is a bony enlargement located between the large bone (metacarpal) of the leg below the knee and one of the small splint bones located on the back part of the large bone. It is generally located on the inside of the leg and is then due to concussion from traveling on hard roads; but it may come on the outside of the leg from an injury, as a blow or a kick. Its seriousness depends upon its location. If it is near the knee joint the lameness is often severe; but if not located near a joint the lameness is generally trifling.
Symptoms. - In walking the animal may not limp much,but will show it plainly in trotting. The lameness is most severe before the enlargement begins to show, but there will be heat in the part and the horse will flinch upon pressure with the fingers. When the enlargement begins to grow it can be easily seen as well as felt.
Treatment. - If discovered before the enlargement begins, shower daily with cold water, and if the lameness continues after the inflammation has been reduced, apply the biniodide of mercury blister, repeating in four weeks if the lameness continues. If there is an enlargement accompanied by lameness, the treatment will be the same; but if there is no lameness, only the blister need be applied, and that will do very little good, as the enlargement cannot be reduced much.