Sacroiliac joint problems are one of many causes of low back pain. Sacroiliac joint dysfunction may be difficult to diagnose. X-rays, CAT scans and MRIs may be normal and several other problems can mimic the pain of SI joint dysfunction. One maneuver called the FABER test can provoke pain caused by SI joint problems. With this maneuver, the patient is lying down and our physician flexes, abducts and externally rotates the hip. If this maneuver reproduces the pain, then the sacroiliac joint may be the problem. If the diagnosis is still unclear, an injection into the joint may give the answer.