Classified as to structure, it has a joint cavity, with the ends of the bones covered by a smooth hyaline articular cartilage; the joint is lubricated and nourished by thick synovial fluid. It is enclosed by a flexible articular capsule. Most permanent joints I the body are synovial, and of all the types of joints, these allow the greatest range of movement (diarthroses), due to their special form of articulation.
Synovial joints (or diarthroses, or diarthroidal joints) are the most common and most moveable type of joints in the body. As with all other joints in the body, synovial joints achieve movement at the point of contact of the articulating bones. Structural and functional differences distinguish the synovial joints from the two other types of joints in the body, with the main structural difference being the existance of a cavity between the articulating bones and the occupation of a fluid in that cavity which aids movement.