Pivot joint

Pivot joint is a type of synovial joint that allows only rotational movement around a single axis. It is also known as a rotary joint. The pivot joint is exemplified by the joint between the atlas and the axis (first and second cervical vertebrae), underneath the skull, allowing the head to turn from side to side.

Structure

The pivot joint is a type of synovial joint. In these joints, the articulating bone ends are covered with articular cartilage and enclosed within an articular capsule that is lined by a synovial membrane. The synovial membrane produces synovial fluid that lubricates the joint and reduces friction and wear.

In a pivot joint, one bone rotates about another. This is achieved where a rounded or pointed surface of one bone articulates with a ring formed partly by another bone and partly by a ligament.

Examples

The most obvious examples of pivot joints in the human body are the atlanto-axial joint, between the atlas and the axis, and the proximal radioulnar articulation, between the radius and the ulna in the forearm. These joints allow for rotation, such as turning the head from side to side or twisting the forearm.

Clinical significance

Injuries or diseases affecting the pivot joints can have significant impacts on mobility and quality of life. For example, rheumatoid arthritis is a chronic inflammatory disorder that can affect multiple joints, including the pivot joints. It can cause pain, swelling, and eventually result in joint deformity and erosion.

See also

• Joint
• Synovial joint
• Ball and socket joint
• Hinge joint
• Saddle joint
• Condyloid joint
• Plane joint

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