Joints of the skeletal system

The skeleton works together with the muscles in enabling the body to move. The bones of the shoulders and arms, for instance, serve as levers against which the muscles that move the arm can pull. The place where bones meet is called a joint. There are two basic kinds of joints. (1) Freely movable joints, such as the elbow, knee, and shoulder joints, permit varying degrees of motion. The bones of a movable joint are held together by bundles of tough, flexible connective tissue called ligaments. (2) Immovable joints do not permit any movement of the bones. The bones of the skull, except for the jawbones, meet in fixed joints.