SCANNING ELECTRON-MICROSCOPY OF HUMAN CORTICAL BONE FAILURE SURFACES

Undecalcified samples extracted from human femoral shafts are fracture d by bending and the fracture surfaces are examined with a scanning el ectron microscope (SEM). The investigation is performed on both dry an d wet (hydrated with a saline solution) specimens. SEM micrographs sho w patterns in many respects similar to those observed in fractography studies of laminated fiber-reinforced synthetic composites. In particu lar, dry and wet samples behave like brittle and ductile matrix lamina tes, respectively. An analysis carried out on the basis of the mechani sms that dominate the fracture process of laminates shows that a reaso nable cortical bone model is that of a laminated composite material wh ose matrix is composed of extracellular noncollagenous calcified prote ins, and the reinforcement is constituted by the calcified collagen fi ber system. Copyright (C) 1996 Elsevier Science Ltd.