Last Updated on March 26, 2022 by Allison Price
The cannon bone is the horse limb that most people are familiar with. The splint bone, a small bone on each side of the cannon bones, is located to the right. Figure 1: The small splint bone is a thin, tapering small knob that runs about two-thirds down the cannon bones.
Causes of splints
The ligament is located between the cannon and splint bones. It is very elastic in young horses. The ligament becomes less elastic as the horse grows older. Ossification can cause inflammation and pain. Further irritation can be caused by jumping, running, and/or working horses during ossification.
Splints are most common in horses between 2 and 5 years of age. Usually, it’s the forelimbs that are affected. Rarely, splints occur in the hind leg. The splint bones of older horses are fused to the cannon bone.
Most splint problems are located on the medial side of the forelimbs. Because it is closest to the knee, the medial splint bones are most commonly the ones that are affected. The lateral (or outer) splint bones has a more slanted top. The medial splint bones bear more weight when the weight is transmitted between them. The ligament between the medial and cannon bones is therefore subject to greater stress than the outer ligament.
Medial view: Left forelimb of horses
Two-year-old horses in training are most likely to experience lameness from splints. Lameness can be most evident when the horse is working, trotting, or just afterward. Lameness can be temporary or permanent for up to a year.
The horse will react to touch of the ossified portion of the ligament by moving his fingers up and down the cannon bone. The length of the splint bone may experience a large or small swelling. The swelling and soreness typically disappears once the ligament has ossified.
Splint bone conditions can be treated by a variety of methods. Veterinarians have many options. The horse should be restrained and placed on soft ground for at most 30 days. Some veterinarians will prescribe medications to reduce inflammation and prevent bone loss. Splint bone disease can heal on its own without the need for medication or treatment.
Most horses are healthy, except for those with large bony growths that interfere with the knee joint. These cases may require surgery.