The hip is the area on each side of the pelvis. The pelvis bone is made up of 3 sections:
Ilium. The broad, flaring portion of the pelvis.
Pubis. The lower, rear part of the pelvis.
Ischium. One of the bones that helps form the hip.
The hip joint is a ball-and-socket joint that allows motion and gives stability needed to bear body weight.
The socket area (acetabulum) is inside the pelvis. The ball part of this joint is the top of the thighbone (femur). It joins with the acetabulum to form the hip joint.
The hip is one of the most stable joints in the body. But because it bears your body weight, it is more likely to develop arthritis because of the extra pressure. Pain in the hip may be caused by injury to muscles, tendons, or the small fluid-filled sacs (bursae) that cushion and lubricate joints.