- The sacroiliac (SI) joint is a common but overlooked cause of lower back pain, accounting for up to 15-30% of cases. It connects the sacrum to the pelvis and is a common site for injury or inflammation. - Diagnosing SI joint pain can be challenging as symptoms often mimic other back issues. Imaging may be misleading and diagnostic SI joint injections are usually needed. Physical exams like distraction, compression, and Patrick's tests can help identify SI joint involvement. - Treatment begins conservatively with physical therapy, bracing, medications, and SI joint injections. For those who fail conservative care, minimally invasive surgery like radiofrequency ablation or SI joint fusion