P3F-8 Elastic Anisotropy and Crystallites Orientation in Bovine Cortical Bone

For the evaluation of osteoporosis using ultrasonic technique, it is important to know the characteristics of ultrasonic waves in the bone. In this study, distribution of ultrasonic wave properties in bovine femur is investigated using an ultrasonic pulse technique, considering the structure in the microscopic level. Especially, focusing on the anisotropy of cortical bone, the effect of crystallites orientation of bone mineral phase (mainly hydroxyapatite) is discussed. To obtain the HAp crystallites alignment, XRD patterns of specimens were measured. The preference ratio of HAp crystallites c-axis was derived by dividing the integral strength of (0002) peak by that of (31-40) peak. One interesting result is the higher BMD and density values of plexiform specimens. The higher BMD and density values mean the existence of large amount of HAp in the plexiform structure. This also seems to affect the high velocities in the plexiform specimens