Last Updated on April 9, 2022 by Allison Price
Hunter’s bump is a term that describes a horse with a prominent tuber sacrale at the top of its rump.
This condition is often referred to as a breed-specific conformation problem. It’s most common in “hunter/jumper”, such as Warmbloods and Thoroughbreds.
This is a common practice in the discipline and some people think it’s a positive thing!
It is usually due to the horse’s use, i.e. It is due to the horse’s job, how it uses its body, or an old injury. There are many opinions on the cause of the problem, and all are likely to be valid.
Horses tend to be multi-road to the exact same imbalance.
What is the Use of a Horse’s Hair?
There are three main theories about hunter’s bump: 1) sacroiliac dysfunction, 2) damage or loss to one or several of the stabilizing ligaments in the pelvis and 3) injury or destruction to one or both of the muscles that act on the pelvis.
The illustrations below show that there are many muscles which affect the action of the pelvis and hip. Any injury to or strain to one of these muscles can have a major impact on the performance of a horse and their range of motion to its hindquarters.
The muscles adjacent to the injured muscle take over when there is injury or strain. The nature of an injury (e.g. if there are ligaments involved) will determine whether the muscles can act as stabilizers to limit the movement of one joint. This is done to prevent further damage.
The compensating soft tissues can become overworked and more susceptible to injury, especially when a condition becomes chronic. Muscles are in constant contraction. They also fatigue easily.
Horses’ bodies continue to compensate for injuries, and certain muscles may become atrophied if they are not used as often. Other muscles become more developed. This new way of moving is embedded in the horse’s muscle memory, and it is less likely that the body will return to balance after healing from the original injury.
Add to that the creation of scar tissue, which isn’t very elastic, and greatly reduces movement to surrounding soft tissue.
Hunter’s bump is caused by constant strain on the sacroiliac joints and ligaments. This can be due to poor footing, jumps, falls and other awkward landings. It can also cause damage to the ligaments. The characteristic “bump” at the horse’s top is caused by the muscle atrophy overlying the tuber Sacrale. This, along with the upward motion of the sacroiliac joints, can cause the horse to have a bump.
Is Hunter’s Bump a Painful Experience?
Many horses suffering from hunter’s bump will also experience lumbar pain. Other conditions may develop if the original injury is not treated for a while. Secondary conditions may develop such as stifle or hock problems. If the primary problem is not addressed, these secondary conditions can often persist or worsen.