ELASTIC PROPERTIES OF HUMAN CORTICAL AND TRABECULAR LAMELLAR BONE MEASURED BY NANOINDENTATION

An experimental investigation was undertaken to measure the intrinsic elastic properties of several of the microstructural components of hum an vertebral trabecular bone and tibial cortical bone by the nanoinden tation method. Specimens from two thoracic vertebrae (T-12) and two ti biae were obtained from frozen, unembalmed human male cadavers aged 57 and 61. years. After drying and mounting in epoxy resin, nanoindentat ion tests were conducted to measure Young's modulus and the hardness o f individual trabeculae in the vertebrae and single osteons, and inter stitial lamellae in the tibiae. Measurements on the vertebral trabecul ae were made in the transverse direction, and the average Young's modu lus was found to be 13.5 +/- 2.0 GPa. The tibial specimens were tested in the longitudinal direction, yielding moduli of 22.5 +/- 1.3 GPa fo r the osteons and 25.8 +/- 0.7 GPa for the interstitial lamellae. Anal ysis of Variance showed that the differences in the measured moduli ar e statistically significant. Hardness differences among the Various mi crostructural components were also observed. (C) 1997 Elsevier Science Limited. All rights reserved.