Radiographic morphometry and radiographic photodensitometry of the femur in the Beagle at 13 and 21 months.

A study was made of x-ray morphometry and x-ray photodensitometry of bones of 2 small groups of healthy standardized colony-raised male research Beagles, ages 13 and 21 months. The morphometry and photodensitometry results were correlated to other variables of interest. The total width of the femur and its optical density to x-rays increased significantly with age and body weight, but not so the length of the femur nor the combined cortical thickness (CCT). This last measurement (CCT) did not increase in parallel with the whole length of the bone either. The CCT/width ratio decreased as body weight increased. The clear-cut increase in the optical density of the whole bone is therefore explained by the age-related variations in bone envelope activity.