MRI demonstrates edema within the gluteus maximus and medius muscles from their origins through their insertions. No fractures identified. The hip joint spaces are fairly well maintained. No pelvic mass is indentified. There is STIR hyperintensity within the actablulum noted on axial STIR image 9 and coronal STIR #8 The bone marrow and soft tissues singal is otherwise normal. There is contusion/partial tearing of the gluteus maximus and medius muscles from their origins through their insertions, most pronounced at the oreigins of the muscles. There is also edema of the right acetabulum. How does this happen, when you have never fallen on you backside? Thanks,