Dysfunction in the sacroiliac joint, or SI joint, is thought to cause low back and/or leg pain. The leg pain can be particularly difficult, and may feel similar to sciatica or pain caused by a lumbar disc herniation.

 

The Sacrollic joint is the joint in the bony pelvis between the sacrum and the ilium of the pelvis , which are joined by strong ligaments. In humans, the sacrum supports the spineand is supported in turn by an ilium on each side. The joint is a strong, weight bearing synovial with irregular elevations and depressions that produce interlocking of the two bones. The human body has two sacroiliac joints, one on the left and one on the right, that often match each other but are highly variable from person to person.