Joint Fluid Interpretation Synovial fluid, often referred as joint fluid, is located in all joints or diarthroses.[1] The synoviocytes also contribute to the local production of cytokines, small-molecule mediators of inflammation, and proteolytic enzymes that degrade the extracellular matrix, therefore being key components of the inflammatory rheumatoid arthritis pathways that affect joints.At the synovial joints, the bones are covered by articular cartilage and are separated from each other by a small cavity that contains the synovial fluid.