Comparison of the skeletal development of wild-type,

Csf1^op/Csf1^op, and Csf1r⁻/Csf1r⁻mice. Radiograms of the heads, bodies, and femurs of mice of the indicated genotypes at different ages (m, months). Each femur is from a different mouse. Arrows indicate regions of increased bone density most easily visualized at this magnification. Also shown is the extent (horizontal line) and fraction (in parenthesis) of the total femur length that is of high radiopacity.