The Hip Joint is a ball-and-socket joint formed by the head of the femur, or thigh bone, and the acetabulum of the pelvis. This union supports weight bearing as well as absorbing the forces created by physical activity, standing, and sitting. Important differences exist in the size and structure of the hip and pelvis in men and women. A woman’s bone structure is slightly less dense than a man’s, and the pelvis is smaller, shorter and wider. Additionally, the bony protrusions for muscle attachment are not as sharply defined.