Educational video describing the sacroiliac joint as a source of low back pain. Due to the proximity of the sacroiliac joint to the hip and the spine, pain of SI joint origin may be attributed to a hip or spine condition rather than the sacroiliac joint itself. SI joint pain is an unappreciated problem causing low back pain . Clinical and radiological evaluation is not usually reliable. The only reliable method for diagnosing SI joint pain is by injection.