Ball-and-socket joint: Consists of a bone with a globular or slightly egg-shaped head that articulates with the cup-shaped cavity of another bone. Such a joint allows a wider range of motion than does any other kind, permitting movements in all planes, as well as rotational movement around a central axis. The hip and shoulder contain joints of this type.
Condyloid joint: The ovoid condyle of one bone fits into the elliptical cavity of another bone, as in the joints between the metacarpals (bones of the palm) and phalanges (bones of the fingers and toes). This type of joint permits a variety of movements in different planes; rotational movement, however, is not possible.
Gliding joints: The articulating surfaces are nearly flat or slightly curved. These joints allow sliding or back-and-forth motion and twisting movements. Most of the joints within the wrist and ankle, as well as those between the articular processes of adjacent vertebrae, belong to this group. The sacroiliac joints and the joints formed by ribs 2 though 7 connecting with the sternum are also gliding joints.
Hinge joint: The convex surface of one bone fits into the concave surface of another, as in the elbow and the joints of the phalanges. Such a joint resembles the hinge of a door in that it permits movement in one plane only.
Pivot Joint: The cylindrical surface of one bone rotates within a ring formed of bone and fibrous tissue of a ligament. Movement at such a joint is limited to rotation around a central axis. The joint between the proximal ends of the radius and the ulna, where the head of the radius rotates in a ring formed by the radial notch of the ulna and a ligament (annular ligament), is of this type. Similarly, a pivot joint functions in the neck as the heard turns from side to side. In this case, the ring formed by a ligament (transverse ligament) and the anterior arch of the atlas rotates around the dens of the axis.
Saddle joint: Forms between bones whose