The sacroiliac joint is one of the most important parts of the horse’s body—and perhaps one of the least understood. This joint, and its related structures, is the connection between the horse’s pelvis and the spine. It functions to allow the transfer of energy from the horse’s powerful hind legs to the pelvis and then to the spinal column. This results in the horse’s all-important forward motion. on.
However, the SI joint is different from other joints, such as the fetlocks or the hocks, in that it has relatively little actual motion itself, has no specific joint capsule, has very little associated joint fluid and is composed of two different types of cartilage. Stability of the SI joint is achieved by a complex ligamentous structure and associated muscles.
Unfortunately, tely, this important and intricate joint is very difficult to evaluate. Due to its location deep in the pelvis and its protection by thick muscles and fat, the equine SI joint is not possible to see or easily palpate (physically touch or manipulate). The size and density of that part of the horse’s body make it hard to obtain conventional radiographs, and ultrasound imaging can also be challenging. The clinical complaints and signs of potential SI problems can also be caused by any number of other issues and conditions in the horse. Consequently, identifying and accurately diagnosing equine SI problems is a significant challenge for
