The hip is an area on each side of the pelvis, and the hip joint is one of the largest weight-bearing joints in the body. It is a ball-and-socket joint that connects the thigh bone (femur) to the hip bone (pelvis). The femur is a long bone with a rounded top that fits into a cup-like socket in the pelvis called the acetabulum. The hip joint offers a wide range of motion and provides support for the legs to hold the body. The function of the hip joint is to provide balance and support for the upper body, move the upper leg, and hold the body weight. The ball-and-socket joint lets the upper leg move at 3 degrees, allowing for flexion, extension, rotation, back-and-forth motion, and circular motion.

The hip joint is made up of bones and joints, ligaments of the joint capsule, muscles and tendons, and nerves and blood vessels that supply the bones and muscles of the hip. The hip joint is surrounded by muscles, ligaments, and tendons, and any injury or disease of the hip will adversely affect the joints range of motion and ability to bear weight. The hip joint is one of the most stable joints in the body, but it is more likely to develop arthritis because of the extra pressure it bears. Pain in the hip may be caused by injury to muscles, tendons, or the small fluid-filled sacs (bursae) that cushion and lubricate joints.

In summary, the hip is an area on each side of the pelvis, and the hip joint is a ball-and-socket joint that connects the thigh bone to the hip bone. It offers a wide range of motion and provides support for the legs to hold the body. The hip joint is made up of bones and joints, ligaments of the joint capsule, muscles and tendons, and nerves and blood vessels that supply the bones and muscles of the hip.