Multiaxial joint

Multiaxial joint

A multiaxial joint (or polyaxial joint) is a type of synovial joint that allows for movement along multiple axes. These joints are characterized by their ability to perform movements in several planes, including flexion, extension, abduction, adduction, and rotation. The most common examples of multiaxial joints in the human body are the shoulder joint and the hip joint.

Structure

Multiaxial joints are composed of several key structures:

• Articular cartilage: This smooth, white tissue covers the ends of bones where they come together to form joints. It enables the bones to move smoothly against each other.
• Synovial membrane: This membrane lines the joint capsule and secretes synovial fluid, which lubricates the joint.
• Joint capsule: A fibrous tissue that encloses the joint, providing stability while allowing movement.
• Ligaments: Strong bands of connective tissue that connect bones to other bones, providing additional stability to the joint.

Types of Multiaxial Joints

There are two primary types of multiaxial joints:

• Ball-and-socket joint: This type of joint features a spherical head of one bone fitting into a rounded socket of another bone. Examples include the shoulder joint (glenohumeral joint) and the hip joint (acetabulofemoral joint).
• Plane joint: Also known as a gliding joint, this type allows for sliding movements in multiple directions. An example is the carpometacarpal joint of the thumb.

Function

Multiaxial joints provide a wide range of motion, making them essential for various activities that require complex movements. For instance, the shoulder joint allows for the arm to move in a full circle and rotate around its axis, which is crucial for activities such as throwing, lifting, and reaching.

Clinical Significance

Due to their extensive range of motion, multiaxial joints are susceptible to injuries such as dislocation, sprains, and arthritis. Proper care, including strengthening exercises and avoiding excessive strain, is important to maintain the health and functionality of these joints.

Examples in the Human Body

• Shoulder joint (glenohumeral joint)
• Hip joint (acetabulofemoral joint)

See Also

• Synovial joint
• Ball-and-socket joint
• Plane joint
• Flexion
• Extension
• Abduction
• Adduction
• Rotation