Sacroilitis is the inflammation of the sacro- iliac joint between the sacrum and the ilium. The joint is very narrow with little range of motion. The causes of SI joint inflammation are arthritis or diseases such as ankylosis spondylitis. The joint is a very narrow with very little range of motion. The causes of SI joint inflammation can be caused by arthritis, or diseases such as ankylosis spondylitis. The symptoms of SI joint inflammation are pain in the region of the SI joint as well as lower back pain. The pain of the SI joint can radiate down the buttock to the mid- thigh. The pain is described as an achy throbbing pain which exacerbate with movement. The diagnosis is made clinically by the physician who can elicit the pain with certain movements to test the joint. Treatments for SI joint pain include medications, as well as SI joint injection therapy. Prolotherapy is a modality that has been used on SI joints to help heal the ligaments which may have increased laxity and cause excess motion in the joint.