The hip joint lies deeply in the root of the lower limb enclosed within a thick mantle of muscle. The periarticular muscles together with their tendons (“living ligaments”) afford protection from trauma but at the same time impede surgical approach and clinical examination. As the liaison between the body trunk and the lower limb, the main functions of the hip joint are the transmission of body weight to the lower limb, and the control of the static and dynamic equilibrium as well as the limb’s position. As is the case with the other weight bearing joints of the lower limb, the hip must be both stable and mobile, corresponding to the biomechanic properties of standing and walking.