Suspensory ligament injuries in horses can affect the animal’s future athletic ability. In order to understand why and how injuries occur, it is helpful to be familiar with the structures involved.
Ligaments attach bones to each other and act as supports. The suspensory ligament in the horse is a strong, broad, fibrous anatomical structure that attaches to the back of the cannon bone just below the knee or hock — the origin of the ligament.
About two-thirds of the way down the cannon bone, the ligament divides into two branches which attach to the inside and outside sesamoid bones, on the back of the fetlock.
In the upper third of the cannon region, the suspensory ligament lies between the large “heads” of the splint bones. This means it is impossible to feel the ligament, or apply pressure directly to it, so diagnosis of damage here is difficult.
Sprain of the suspensory ligament (suspensory desmitis) is usually restricted to one of three areas:
- injury to the upper third of the ligament (called high, or proximal, suspensory desmitis) is common in horses in all disciplines
- injury to the middle third, or body, of the ligament is easiest to diagnose, but least frequent. National Hunt racehorses and point-to-pointers are most likely to suffer this injury, called body desmitis.
- damage to the inside or outside branch of the suspensory ligament is also common, particularly in horses which jump, called branch desmitis.
Signs of suspensory desmitis
A ligament sprain causes heat, swelling and pain. When the middle third, or body, of the suspensory ligament is sprained the signs are easy to detect as there is often obvious swelling that can be seen on both the inside and outside of the injured leg.