The sacroiliac joints, or SI joints, exist on both sides of the lower back, joining the spine to the pelvis. These joints are susceptible to injury, either by chronic stress or acute injury. This type of pain may occur with other spine problems and the diagnosis of sacroiliac arthropathy is frequently overlooked. The joint is injected with local anesthetic and steroid under X-ray guidance. Typically, this is a difficult joint to inject and requires precision needle placement and confirmation of correct placement by documentation of appropriate contrast spread. Injections may be repeated multiple times to effect long-term relief. Best results occur when the injections are performed in coordination with physical therapy.