The sacroiliac joint (SIJ) is the largest axial joint in the body. In the U.S., the exact prevalence of SIJ pain—a subtype of lower back pain—is unknown, but it is estimated that patients with SIJ pain could represent up to 15% of all patients seen in outpatient clinics with chronic lower back pain.
Causes of sacroiliac pain may include arthritis, traumatic injury, pregnancy and postpartum, systemic inflammatory conditions, and infection.
Symptoms of SIJ dysfunction may include the following: