Structural Joints: Synovial Joints

Synovial joints are diarthroses or articluations formed between bones that move freely against each other, such as the joints in the limbs.

Articular cartilage, a type of hyaline cartilage, covers the adjoining bones and reduces friction during joint movement.

The articular or joint capsule is a fibrous connective tissue enclosing the joint. Its dense outer tissue attaches to the periosteum of the articulating bones, whereas the loose inner tissue forms the synovial membrane that produces the synovial fluid. 

The synovial membrane is supplied by a network of blood vessels. These vessels act as a source of blood plasma which is filtered to form the synovial fluid.

The synovial fluid fills the cavity between the articulating bone surfaces and functions as a lubricant and shock absorber. It also helps to distribute nutrients to the surrounding cells.

Bands of thickened fibrous tissue outside the articulating surfaces form the capsular ligaments that strengthen the synovial joint.

The capsule and ligaments contain sensory nerves that monitor the joint movement and sense pain.