Where does normal synovial fluid come from?
The synovial fluid is a selective transudate of plasma. Large molecules such as clotting factors are excluded and therefore normal synovial fluid does not clot spontaneously. Synovial fluid is viscous like an egg white (synovial is derived from ovum , Latin for egg) due to hyaluronic acid produced by fibroblast-derived type B synoviocytes and contributes to the lubricating function of the fluid. With inflammation, cells with their degradative enzymes enter the joint cavity breaking down the hyaluronans causing the synovial fluid to become less viscous. In addition, clotting factors gain entry causing the synovial fluid to clot spontaneously.