Plane joint

Plane joint or gliding joint is a type of synovial joint which allows bones to glide past one another in any direction along the plane of the joint - up and down, left and right, and diagonally. Such joints are characterized by their flat or slightly curved surfaces that slide over one another. Plane joints are found in areas of the body where flexibility and gliding motions are necessary but where there is not a significant amount of rotation or angular movement. Examples of plane joints include the intercarpal joints of the wrist, intertarsal joints of the foot, and the joints between the articular processes of the vertebrae.

Structure

Plane joints are formed by the articulation of two flat bone surfaces that fit snugly together. The bones in a plane joint are covered by a thin layer of hyaline cartilage, which reduces friction and allows the bones to glide smoothly over each other. Surrounding the joint is a joint capsule that is filled with synovial fluid, a lubricating liquid that further reduces friction and facilitates movement. The joint capsule is lined with a synovial membrane that produces the synovial fluid.

Function

The primary function of plane joints is to allow for small, gliding movements. These movements are limited by the shape of the bones, the strength and flexibility of the surrounding ligaments and muscles, and by the tightness of the joint capsule. Plane joints provide stability to the skeletal structure while also allowing for a degree of flexibility and mobility. This type of joint is crucial for complex movements and for distributing loads evenly across the joint surfaces.

Examples

• Intercarpal joints of the wrist: These joints allow for the slight gliding movements of the carpal bones, contributing to the flexibility and range of motion of the wrist.
• Intertarsal joints of the foot: Similar to the intercarpal joints, the intertarsal joints facilitate the gliding movements of the tarsal bones, aiding in the foot's ability to adapt to different surfaces and in the distribution of body weight.
• Articular processes of the vertebrae: The joints between the superior and inferior articular processes of adjacent vertebrae allow for slight movements that contribute to the flexibility of the spine.

Clinical Significance

Injuries or diseases affecting plane joints can lead to pain, stiffness, and reduced mobility. Conditions such as osteoarthritis can cause the cartilage in these joints to degrade, leading to increased friction, inflammation, and pain during movement. Treatment for plane joint issues may include physical therapy, medication to reduce pain and inflammation, and in severe cases, surgery to repair or replace the damaged joint.

See Also

• Synovial joint
• Joint capsule
• Synovial fluid
• Hyaline cartilage
• Osteoarthritis

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