Fundamental Investigation of Strength Indexes of Human Bones Using Natural Frequencies of Forearm

Abstract

The quality and the strength of human in-vivo bones are considered concerning the decrease of bone mass with aging and the health of bones. In this paper the strength is evaluated by indexes with respect to the Young's modulus and the flexural rigidity, which are derived from the product(fL)of natural frequencies(f)of ulna and the length(L). The natural frequencies were measured by impulse excitation and FFT technique. Total bone density and trabecular density were measured by the peripheral Quantitative CT(pQCT)method and then the cortical region was analyzed. These densities are compared with the strength indexes for 343 females of 20 to 88 years old. It is shown that the decrease of the strength indexes with aging is much larger than of total bone density being used for screening of osteoporosis.