Esta foto de Autor desconocido está bajo licencia CC BY-NC-ND JOINTS HINGE JOINTS AND BALL-AND-SOCKET JOINTS HINGE JOINTS BALL-AND-SOCKET JOINTS STRUCTURE OF MOVEABLE JOINT Synovial joints, also known as movable joints, refer to the joints that are capable of moving in a variety of directions (allow mobility). Such examples include the knee joints, elbow joints, wrist joints, shoulder joints, hip joints and ankle joints. The main function of the joints is to allow both movement and flexibility. They tend to be classified by the degree of their possible movement, the number of bones involved and the complexity of the joint.