Electric and dielectric properties of wet human cortical bone as a function of frequency

In this paper, the electrical and dielectric properties of wet human cortical bone from a distal tibia were examined as a function of frequency and direction. The resistance and capacitance of the cortical bone specimens were measured at near 100% relative humidity. The measurements were made in all three orthogonal directions at discrete frequencies ranging from 120 Hz to 10 MHz using an LCR meter. At a frequency of 100 kHz, the mean resistivity and specific capacitance for the ten cortical bone specimens were 1.55 k omega-cm and 33.81 pF/cm in the axial direction, 15.79 k omega-cm and 9.98 pF/cm in the circumferential direction, and 21.5 k omega-cm and 9.83 pF/cm in the radial direction. All electrical and dielectric properties except the resistivity and the specific impedance were highly frequency dependent for the frequency range tested. However, the resistivity and specific impedance were relatively less frequency dependent. All electrical and dielectric properties were also transversely isotropic in nature, the values for the axial direction being different from the values obtained for the two transverse directions.