[Contribution of scanning electron microscopy to the study of normal and pathological human synovial membrane]

Scanning electron microscopy permits three-dimensional morphological study of the outer layer of the synovial membrane. This article concerns the study of 15 surgical samples of normal and pathological human synovial membranes: 3 normal synovial membranes, 6 inflammatory synovial membranes, 5 arthrosic synovial membranes, 1 tuberculous tenosynovitis. The samples were washed, fixed in a mixture of glutaraldehyde and iso-osmotic paraformaldehyde, dehydrated in increasing concentrations of alcohol and at the critical point, and then subjected to double metallization (aluminium and gold). Certain portions were treated with hyaluronidase. Hypertrophy of the villi, considerable in inflammatory synovial membranes, minimal in arthrosic synovial membranes, and absent in the normal synovial membrane, was confirmed. The outer layer is composed of cells of different sizes with spaces betwen, in which images indicating intercellular bridges can just be seen. The surface of the cells is irregular and covered with numerous microvilli. The arthrosic synovial membrane is poorly with large cells; in contrast in an inflammatory synovial membrane they are numerous, globular, and project from the surface.