The fracture I am describing here is one in which the cannon bone breaks completely (and usually into many fragments) and weight bearing ability is lost.

In the adult horse, this is almost always caused by a hard blow, usually a kick from another horse. In foals, with more fragile cannon bones, it is seen when another horse steps on their cannon bone.

This injury presents as a non-weight bearing lameness in which the lower limb loses its form, often hanging at a bizarre angle. If the lower limb is manipulated, it can be moved in an outward plane in a way that would be impossible if the bone was intact.

Often there is a severe wound associated with it. It is often a compound fracture, meaning that the fractured end of bone has protruded through the skin. In these cases, the large vessels that run along the cannon bone may be cut, causing severe bleeding.

This is a catastrophic injury. In most cases, prompt euthanasia is the only reasonable option. For horse owners with the financial and emotional resources to pursue treatment, there may be other options.

The attending vet will usually splint the limb with a heavy and bulky bandage and full splint. Referral to a veterinary teaching hospital with a qualified orthopedic surgeon is the only option. In some cases given today's knowledge and technology, these fractures can be repaired with acceptable results.