The sacroiliac joint is the largest joint in the human spine. It is located in the lower back just above the tailbone. Inflammation of the sacroiliac joint is often overlooked as a cause of low back and buttock pain. A sacroiliac joint injection is a simple procedure to determine whether or not pain is originating from the sacroiliac joint, and it is also a way to potentially eliminate it. This procedure is performed using real-time imaging. Some patients may also benefit from a Sacroiliac joint radiofrequency ablation which can provide several months to years of relief.