The hip bone’s primary function is to support the weight of the body and enable walking. Similar to the shoulder, the hip is a mobile joint. The anatomical structure of the hip (or hip bone), allows movement of three pairs of principal directions. However, in comparison to the shoulder, the hip has a more restrictive range of motion which subsequently increases the joint’s stability, since the articular surface of the acetabulum and femur are fully fused together.
The hip joint is reinforced by a strong articular capsule and four ligaments, the iliofemoral, pubofemoral, ischiofemoral and ligamentum teres ligaments which enable flexion-extension and hyperextension, abduction-adduction and internal-external rotation movements.