Sacroiliac joints are located in the pelvis and are a frequent source of back pain and posterior hip pain. They can also be the source of pain that radiates into the legs. We can determine if the sacroiliac joint is the source of pain by injecting local anesthetic into the joint. If this relieves the pain it confirms that the joint is the source of the person’s pain. Injecting cortisone into the sacroiliac joint can provide pain relief for months or years.