Pivot joint

Pivot joint
1: Ball and socket joint; 2: Condyloid joint (Ellipsoid); 3: Saddle joint; 4 Hinge joint; 5: Pivot joint;
Latin	articulatio trochoidea
Gray's	subject #70 285

A pivot joint (trochoid joint, rotary joint, Lateral Ginglymus) is a type of diarthrosis. In pivot joints, the axis of a convex articular surface is parallel with the longitudinal axis of the bone.

Pivot and hinge joints can be both considered cylindrical joints.^[1]

Movements

Pivot joints allow for rotation, which can be external (for example when rotating an arm outward), or internal (as in rotating an arm inward). When rotating the forearm, these movements are typically called pronation and supination. In the standard anatomical position, the forearms are supinated, which means that the palms are facing forward, and the thumbs are pointing away from the body. In contrast, a forearm in pronation would have the palm facing backward and the thumb would be closer to the body, pointing medially.

Examples

Examples of a pivot joint include:

• Proximal radioulnar joint
• Distal radioulnar joint
• Median atlanto-axial joint

In contrast, spherical joints (or ball and socket joints) such as the hip joint permit rotation and all other directional movement, while pivot joints only permit rotation.

References

External links

• Synovial Joints-Pivot Joints from The University of Michigan Medical School

This article incorporates text from a public domain edition of Gray's Anatomy.

Eva Salugsugan