Splints

Splints is an ailment of the horse or pony, characterized by a hard, bony swelling, usually on the inside of a front leg, lying between the splint and cannon bone or on the splint bone itself. It may be "hot," meaning that it occurred recently and is still painful; or "cold," meaning that the splint has completely recovered and there is no longer any swelling or pain associated with it. Bucked shins are sometimes called 'shin splints,' which involve small stress fractures of the dorsal cannon bone, often seen in race training, and discussed elsewhere.

Anatomy

The splint bones, (metacarpal or metatarsal II and IV), which are remnants of two of the five toes of prehistoric horses, run down either side of the cannon bone. They narrow as they go from the carpal or tarsal joint down, and form a "button" at the bottom or their length, a few inches above the fetlock. Splint bones are attached to the cannon by the interosseous ligament, providing some mobility in the young horse. As the horse ages, the interosseous ligament is typically replaced by bone. In some older horses, the cannon and splint bones may become completely fused.