The hip joint is the largest joint in the body and is the connecting part of the trunk and lower limbs. It has its unique anatomical features and functions. The hip joint is a ball and socket joint, consisting of the femoral head and the acetabulum. The iliac bone at the back of the pelvis, the sit bones at the lower front and the pubic bone above together form the hip joint fossa. The femur forms a spherical knob-like head at the end, and the femoral head is embedded in the socket to form the bony structure of the hip joint. Between the bony structures is a cartilaginous lining that serves to cushion the bony tissue from pressure. A solid joint capsule wraps around the bony tissue outside, making the overall structure of the hip joint extremely strong and capable of adapting to the requirements of upright walking. The hip joint is one of the largest joints in the body and is a major weight-bearing joint. When walking, the weight-bearing stress on the hip can be five times the weight of a person. Changes in the hip due to disease or injury will significantly affect gait and place abnormal stresses on the joint above and below the hip resulting in a range of hip disorders. The hip joint is the largest weight-bearing joint in the body. Not only does it provide the connection between the lower extremities and the trunk, but it also helps a person perform weight-bearing activities.