Pivot joint

Pivot Joint

Diagram of a pivot joint

A pivot joint is a type of synovial joint in the human body that allows for rotational movement around a single axis. This type of joint is characterized by a cylindrical bone that rotates within a ring formed by a second bone and a ligament. Pivot joints are crucial for various movements and are found in specific locations in the body.

Structure

Pivot joints consist of a bony pivot surrounded by a ring of bone and ligament. The pivot is typically a rounded or pointed end of one bone that fits into a ring-like structure formed by another bone and a ligament. This configuration allows for rotational movement around the longitudinal axis of the pivot bone.

Function

The primary function of pivot joints is to allow for rotation. This type of movement is essential for various activities, such as turning the head from side to side or pronating and supinating the forearm. The rotational movement provided by pivot joints is crucial for the flexibility and range of motion in the areas where they are located.

Examples

There are two main examples of pivot joints in the human body:

• Atlantoaxial joint: This joint is located between the first and second cervical vertebrae, known as the atlas and axis, respectively. It allows for the rotation of the head from side to side.

• Proximal radioulnar joint: This joint is found in the forearm, where the head of the radius rotates within the radial notch of the ulna. It enables the pronation and supination of the forearm.

Related Pages

• Synovial joint
• Atlantoaxial joint
• Proximal radioulnar joint
• Rotation (anatomy)