  Using the analytic and experimental techniques we present an exploratory
study of the mass distribution features of the high coincidence of centre of
mass of heterogeneous bone tissue in vivo and its centroid of geometry
position. A geometric concept of the average distribution radius of bone issue
is proposed and functional relation of this geometric distribution feature
between the partition density and its relative tissue average distribution
radius is observed. Based upon the mass distribution feature, our results
suggest a relative distance assessment index between the center of mass of
cortical bone and the bone center of mass and establish a bone strength
equation. Analysing the data of human foot in vivo, we notice that the mass and
geometric distribution laws have expanded the connotation of Wolff's law, which
implies a leap towards the quantitative description of bone strength. We
finally conclude that this will not only make a positive contribution to help
assess osteoporosis, but will also provide guidance to exercise prescription to
the osteoporosis patients.
