Radiographs of femurs from control (A and C) and estradiol-treated (B, D and E) mice. In control femurs (A and C), note that the marrow space and cortical margins are apparent but cannot be seen in specimens from estradiol-treated mice (B, D and E). Femurs marked A and B, and those marked C, D and E were radiographed as a group on the same X-ray film using one exposure to eliminate variability in exposure and development of the films.
Gruber et al. BMC Cell Biology 2001 2:3 doi:10.1186/1471-2121-2-3