Pivot joint


In animal anatomy, a pivot joint is a type of synovial joint. In pivot joints, the axis of a convex articular surface is parallel with the longitudinal axis of the bone.
According to one classification system, a pivot joint like the other synovial joint —the hinge joint has one degree of freedom. Note that the degrees of freedom of a joint is not the same as the same as joint's range of motion.

Movements

Pivot joints allow for rotation, which can be external, or internal. 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:
In contrast, spherical joints such as the hip joint permit rotation and all other directional movement, while pivot joints only permit rotation.