The Human Fetal Synovium. Histology, Fine Structure and Changes in Organ Culture

Fetal synovial tissues were obtained postmortem and maintained in organ culture. Preservation and morphologic differentiation was followed histologically for 2–4 weeks. The lining cells of the fetal synovium was found to consist of three cell types: fibroblasts, macrophages and undifferentiated cells. In culture the undifferentiated cells disappeared and the typical macrophages became scarce. Other changes observed were an apparent increase in mast cells, an intracellular accumulation of lipid inclusions, dilated endoplasmic reticulum, and intracellular collagen fibers.