Previous morphological studies on human bone have demonstrated that veil-like structures ('tensulae') occur in highly stressed regions, i.e. the interface between cartilage and bone. In the present report we describe the distribution of tensulae within various types of human bone by means of scanning electron microscopy and light microscopy. Tensulae were predominately located within bone tissue adjacent to mineralized cartilage. The surface diameter of tensulae ranged from minimal 50 to maximal 400 microns. Occasionally, collagen fibers extended from the interface between cartilage and bone to tensulae. Frequently, the latter were attached to fat cells as well as bone marrow cells. An elemental analysis of tensula revealed high levels of calcium and phosphorus of equal concentrations. However, bone tissue contained higher levels of calcium compared to phosphorus. Additionally, a monoclonal antibody was generated by immunizing rats with bone marrow of mice. Within bone tissue this monoclonal antibody selectively stained membrane-like structures which were clearly identified as tensulae. From our investigations we conclude that the function of tensulae in bone may be to absorb stress in regions where large forces are applied.
