AbstractThe spatial distribution of biologically relevant elements within bone matrix was investigated using electron probe X-ray microanalysis of frozen-dried bulk specimens of cortical bone tissue. Compositional images of calcium, phosphorus, sulfur, and chlorine are presented along with the corresponding secondary electron images: These data indicate that calcium and phosphorus X-rays detected from regions of bone matrix vary little in X-ray intensity as a function of location within the matrix. Most of the sulfur and chlorine X-rays detected originate in regions corresponding to the marrow cavity or to surrounding connective tissue. However, higher magnification X-ray maps reveal the presence of both elements within bone matrix with localizations occurring in regions corresponding to lacunae and surrounding bone matrix. (The J Histotechnol12:23, 1989).