Synovial membrane
The synovial membrane (also known as synovium or stratum synoviale)[help 1] is the soft tissue found between the joint capsule and the joint cavity of synovial joints. It secretes the synovial fluid, which fills the joint cavity and lubricates the joint.
Structure
The synovial membrane is variable but often has two layers
Where the underlying subintima is loose, the intima sits on a pliable membrane, giving rise to the term synovial membrane.
This membrane, together with the cells of the intima, provides something like an inner tube, sealing the synovial fluid from the surrounding tissue (effectively stopping the joints from being squeezed dry when subject to impact, such as running).
The surface of synovium may be flat or may be covered with finger-like projections or villi, which, it is presumed, help to allow the soft tissue to change shape as the joint surfaces move one on another.
