I have low back pain that I suspect might be my sacroiliac joint. How can I know for sure?

Orthopedic surgeons, osteopathic physicians, chiropractors, and physical therapists are trained to test for sacroiliac joint (SIJ) pain. They use a series of tests called pain provocation tests. By using certain positions or movements, the pain is reproduced to confirm the diagnosis. If three or more of the tests are positive, then it's likely the SIJ is the problem.

To know for sure you can also use an injection of a short-acting local anesthetic right into the joint. If you get at least 50 percent reduction of pain for one hour, then the injection is proof that the cause of the pain was the SIJ.

Treatment is then aimed at the SIJ. Sometimes this means using a second, longer acting anesthetic. In other cases posture or movement problems causing the SIJ problem may be treated by a physical therapist.