Structural Classification of Joints

Joints can be structurally classified into fibrous, cartilaginous, and synovial joints based on the type of associated connective tissue and the presence of a synovial cavity between the articulating bones.

Fibrous joints are connected by dense irregular connective tissue composed of collagen fibers.

Fibrous joints fixed by short tissue fibers are not movable—for example, sutures present between the skull bones. In comparison, fibrous joints connected with long tissue fibers are slightly movable—for example, the joint between the shafts of the radius and ulna.

Cartilaginous joints are connected by cartilaginous connective tissues, such as hyaline cartilage and fibrocartilage.

The joints fixed by hyaline cartilage are mostly immovable—for example, the first sternocostal joint. The joints with fibrocartilage discs are slightly movable—for example, the intervertebral joints.

Synovial joints have a fluid-filled cavity with articulating bone surfaces covered by articular cartilage and the joint is surrounded by fibrous connective tissue. These joints are freely movable— for example, the knee joint.