Components of the fibrinolytic system in synovial joints. Normal bovine compared with normal and abnormal human synovial joints.

Fibrinogen is not normally found in human synovial fluid (Ropes and Bauer, 1953) or in bovine synovial fluid (Cho and Neuhaus, 1960). Normal synovial joints are quite rapidly cleared of fibrin after injury (Harrold, 1961). In rheumatoid arthritis and tuberculous arthritis, fibrinogen entering the joint is precipitated as fibrin and in many cases this is not removed but remains to form fibrin bodies (Fig. 1) or to be incorporated in the inflammatory pannus.