Pathology and Pathogenesis a Pathologic Finding: chronic synovitis In acute phase: effusion and cell infiltration In chronic phase: the number of synoviocyte, new capillary mononuclear cells remarkably increases the pannus(血管翳) protrudes into the joint cavity as villous Pannus erodes cartilage, bone 类风湿性关节炎滑膜病理 Normal Diarthrodial Joint gaments and tendons Periosteum bone plate. Articular cartilage Synovial fluid Muscle novum LigamentPathology and Pathogenesis  Pathologic Finding： chronic synovitis In acute phase: effusion and cell infiltration In chronic phase: the number of synoviocyte, new capillary mononuclear cells remarkably increases  the pannus(血管翳) protrudes into the joint cavity as villous  Pannus erodes cartilage, bone, ligaments and tendons