Solution

Synovial joints are produced by freely movable joints. The ends of the bones forming these joints are bound together by an articular capsule formed out of ligaments. The ends of the bones forming the joints are covered with articular cartilage, which protects the bones and reduces friction. Synovial joints can be subdivided into the following groups according to the type of movement they carry out --- hinge joints - occur where the convex surface of one bone fits into the concave surface of another bone, so making movement possible in one plane only. Examples of these joints are the knee and the elbow joints; gliding joints - this type of joint allows for gliding movements between flat surfaces as the surfaces slide over one another. Only a limited amount of movement is allowed such as the joints between the carpal bones, the joints between the tarsal bones; pivot joints allow rotational movement in a single plane - the rotation of the atlas on the axis. Fibrous (or immovable) joints are firmly held together by a thin layer of strong connective tissue. There is no movement between the bones such as the sutures of the skull and the teeth in their sockets.