Fig. 2.

Relationship between instantaneous modulus (E_i) and instantaneous strain (ε_i) of cortical bone at longitudinal, circumferential and radial directions. Exponential regression was fitted for experimental data with instantaneous strain less than 2% from three orientations: longitudinal direction (E_i = 22.1e^−62.4s_i, R² = 0.83), circumferential direction (E_i = 8.79e^−46.3s_i, R² = 0.45), and radial direction (E_i = 6.44e^−37.5s_i, R² = 0.42).