Experimental investigation of local elastic properties in a trabecula of bovine femur

Micro-Brillouin scattering (μ-BR) and scanning acoustic microscope (SAM) techniques were applied to evaluate the elasticity of a small area in a trabecula. Both techniques have similar spatial resolutions (10 μm and 8 μm), which enable the measurements of bone elastic properties without the macroscopic structure effects. Acoustic impedances measured by SAM in a trabecula were in the range of 5-12 Mrayl. Wave velocity values determined by μ-BR were in the range of (4.75-5.11)×10³ m/s. The spatial distribution of both variables exhibited a similar trend of variation across the trabeculae. The acoustic impedance and wave velocity showed a positive correlation (R²=0.63, p<;0.01). Despite the difference in wave propagation direction and measurement frequency, this result suggests that Brillouin scattering technique could be useful for the evaluation of in-plane stiffness in a trabeculae. It can provide additional information compared to SAM or nanoindentation to assess elastic anisotropy.