Elastic properties of microstructural components of human bone tissue as measured by nanoindentation

The elastic properties of several microstructural components of dry human v ertebrae (T-12 and L-l) and tibiae have been investigated in the longitudin al and transverse directions using nanoindentation. The largest Young's mod ulus was that for the interstitial lamellae in the longitudinal direction ( 25.7 +/- 1.7 GPa). This was followed in decreasing order by osteons in the longitudinal direction (22.4 +/- 1.2 GPa), trabeculae in the longitudinal d irection (19.4 +/- 2.3 GPa), an average over osteons and interstitial lamel lae in the transverse direction [16.6 +/- 1.1 GPa (it was difficult to micr ostructurally distinguish osteons from interstitial lamellae in the transve rse direction)], and trabeculae in the transverse direction (15.0 +/- 2.5 G Pa). An ANOVA statistical analysis revealed that the values all are signifi cantly different (p < 0.05). Since the elastic moduli in the longitudinal d irection are all greater than in the transverse, measurable elastic anisotr opies exist in the components. The hardnesses also varied among the microst ructural components in the range 0.52-0.74 GPa. (C) 1999 John Wiley & Sons, Inc.