The joint, or articular, of a synovial joint encloses the joint and prevents bone ends from being pulled apart.

The joint, or articular, capsule of a synovial joint encloses the joint and prevents bone ends from being pulled apart. The capsule is made up of two layers: the fibrous membrane on the outside and the synovial membrane (or synovium) on the inside.

Step 1: The fibrous membrane is made of dense connective tissue that is flexible yet strong. This layer gives the joint its shape and prevents the bone ends from being pulled apart.

Step 2: The synovial membrane lines the joint capsule and secretes synovial fluid. This fluid lubricates the joint, reduces friction between the articular cartilage of the joint during movement, and supplies nutrients to the cartilage.

Step 3: The joint or articular capsule also contains ligaments that help provide additional stability to the joint. These ligaments can be either extracapsular (outside the joint capsule) or intracapsular (inside the joint capsule).

Step 4: The joint capsule also has a rich nerve and blood supply to help control the movements of the joint and detect pain signals.

So, the joint or articular capsule of a synovial joint plays a crucial role in maintaining the stability of the joint and facilitating smooth movements.