"Senile" or age-related bone loss affects cortical and trabecular bone and may be detected in the appendicular as well as the axial skeleton. This study presents radiographic photodensitometry as a precise and sensitive technique for evaluating appendicular skeletal status. Data from reproducibility studies indicate that the coefficient of variation for the technology is between 1.9% and 4.5% for the three bones analyzed. Evaluation of age-related changes in bone mass for over 800 subjects demonstrated a decline in mass vs. age after the fourth decade in women, with the slope of the decline being very similar to that seen in CT longitudinal studies. Applied serially to a patient over time, the technology identifies changes in bone mass and may be used to evaluate the response to intervention therapy.