Distribution of longitudinal wave velocity and hydroxyapatite crystallite orientation in bovine cortical bone

The relationship between the ultrasonic wave velocity and the preferred orientation of HAp crystallites in bovine cortical bones was investigated. The distribution of velocity in the bone axis direction was measured considering the micro-structure and BMD. Cortical bones of four bovine left femurs were used and ring-shaped cortical bone specimens from the middle shaft were obtained. An ultrasonic pulse-echo method was used for the measurement of the longitudinal wave velocity. A pair of wideband self-made polyvinylidene fluoride (PVDF) transducers were used. The received signal was changed into the electric pulse signal, and amplified by a 40 dB preamplifier. Finally, the waveform of the signal was observed using a digital oscilloscope. A significant correlation between the velocity and the preferred orientation of HAp crystallites was observed in the bone with a plexiform structure.