The sacroiliac (SI) joint is part of the human pelvis, located in the lower back, and is responsible for connecting the other pelvic bones to the lowest part of the spine. There are two SI joints, each sitting on one side of the sacrum. These joints are providing stability and flexibility to the lower portions of the spine. Arthritic changes or trauma to the SI joint can cause referred sciatic pain and general lower back pain. The sacroiliac joint injections are used to both diagnose and treat the pain. The medications injected consist of a local anesthetic and a depo-steroid, providing both short and long-term pain relief. If the patient experiences pain relief, a series of injections or Radio Frequency Ablation may be recommend to provide long-term results.