The effects of castration on size and appearance of Sharpey's fibers of rat femurs: A scanning electron microscopic and microradiographic study

Areas of Sharpey fiber bone from the proximal posterior diaphyseal surfaces of anorganic control and castrate osteopenic rat femurs were examined with the scanning electron microscope (SEM). The diameter of Sharpey fiber bundle insertion sites from castratre bone was significantly greater (P less than 0.001) than that from control bone. The fiber bundle insertions appeared as small pits and projections in control bone and as large pits in castrate bones. Microradiographs of cross sections of the Sharpey fiber bone revealed a greater (P less than 0.05) area of outer, lamellated periosteal bone in the castrates than in the controls, suggesting an accelerated bone apposition rate along castrate osteopenic femoral periosteal surfaces.