Ultrasonic determination of the elastic modulus of human cortical bone.

The elastic modulus (Cii) of the cortical bones of 19 individuals (14 femurs and 16 tibias, fixed in formalin) was determined ultrasonically. Elastic moduli were measured at four anatomical positions (anterior, posterior, medial and lateral) and in all three planes of orientation (transverse, longitudinal and radial). The mean tibial Cii (34.11 GPa) was greater than that obtained for femurs (32.52 GPa). The tibial longitudinal plane Cii (34.1 GPa) was significantly greater than the femoral longitudinal plane Cii (32.5 GPa). Cii was significantly higher in the tibia than the femur in both the medial and posterior anatomical positions. The anterior tibia had a significantly lower C11 compared to other positions. Cii was significantly higher in the longitudinal plane than the transverse or radial planes in both the femur and the tibia. There was no consistent difference in modulus between left and right sides. No age effects were observed. There were no significant differences between males and females, or between African Americans and European Americans.