A University of Minnesota study reported that of 124 cases of suspected back pain in horses seen at their clinic over five years, over half of the horses had a sacroiliac-area problem.
At the University of California, researchers examined the spines of 36 Thoroughbred racehorses euthanized for unrelated reasons and found acute injury or degenerative/arthritic changes in the sacroiliac joint in all the horses.
In the United Kingdom, the Animal Health Trust reported dressage and jumping horses to be high risk for sacroiliac region pain.
Clearly, the sacroiliac region needs to be seriously considered any time a horse is off behind or has back pain.
What Is The Sacroiliac?
The sacrum is the end portion the horse's spine. If you press a finger firmly along the middle of the horse's back and move your finger back toward the tail, you'll feel a prominent dip a short distance past the flank. This is the lumbosacral space and marks the spot where the lumbar vertebrae end and the sacrum starts.
The ilium is one of three bones that make up the pelvis. It's shaped roughly like a wing, or the broad, flat section of a moose antler without the spikes, and is the most forward part of the pelvis.
Put It To Use
• Diagnosis involves ruling out other causes.
• Check for clues: less flexible back, lead preferences, activities.
• Make tincture of time work for your horse.
• Assume a full recovery is possible in most cases.
• Weigh hunter's bump involvement.
The sacroiliac joint is the junction between the horse's spine at the sacrum ("sacro") and the pelvis at the ilium ("iliac"). The joint is buried under the heavy gluteal muscles of the top of the horse's rump, lying just off the midline on both sides, on a line drawn between the back edge of the tuber sacrale and the spine. It sits at about the highest point of the rump. The tuber sacrale is the bony prominence just behind the flank that is commonly called the "point of the hip," although it has nothing to do with the hip joint.
This area has two sets of ligaments, either of which can be damaged and cause pain. The dorsal sacroiliac ligaments run from the tuber sacrale ("point of the hip") over to the top of the sacrum. They don't involve the sacroiliac joint directly, but they do help anchor the ilium to the sacral spine.
The ventral sacroiliac ligaments are located deeper, in the area of the sacroiliac joint itself, which they stabilize. This assembly is designed to hold the horse's pelvis tightly to his spine. A normal sacroiliac joint is capable of little movement and contains minimal amounts of joint fluid.