The tail bone (sacrum) and hip bone (ilium) join to form the sacroiliac (SI) joint in the pelvis. This joint is surrounded by dense ligaments and powerful buttock muscles that support this important joint. Lifting objects and prolonged sitting and standing is commonly painful when this joint is irritated. Symptoms consist of a sharp/achy pain directly over the SI joint in the upper buttock and may radiate into the thigh and groin. Excessive stress due to bending, lifting, prolonged sitting in combination with a weak core and gluteal muscles can stress this joint and its surrounding network of ligaments. Manipulation and treatment to eliminate scar tissue provides significant relief and return to normal function.  Proper stretching and strengthening of the core and buttocks is highly preventative of this injury.