Microelasticity of Bone

Despite the complex hierarchical organization and the astonishing variety of bones, it was recently possible to identify a few elementary mechanical components at the micro and nanolevel of the material: hydroxyapatite crystals, collagen molecules, and water. The mechanical properties (i.e. elasticity) of these elementary components are (up to experimental scattering) the same for all bones; they are’ universal’, i.e., independent of tissue-type, species, and anatomical location. The mechanical interaction between these elementary components (mechanical morphology) and the dosages of these components in different tissues determine the macroscopic material properties. Whereas the mechanical interaction is limited to certain patterns, it is mainly the tremendous number of different dosages of the elementary components by which nature produces the admirable diversity of different bones.