Special features of the microdeformation of compact human bone tissue

Abstract

1. An x-ray diffraction study on samples of a compact bone tissue at small and large diffraction angles has been carried out for the first time. 2. It has been found that during stretching the hydroxyapatite crystals in a compact bone tissue are not deformed in proportion to the deformation of the sample. In the initial loading stage, which corresponds to physiological loads, the crystal is deformed only slightly. At deformations of the sample ranging from 0.3 to 0.5% the microdeformability of hydroxyapatite increases steeply, but at deformations e11 > 0.5% it decreases noticeably. 3. At the moment a stretched compact bone tissue ruptures the microdeformation of hydroxyapatite can attain the value of 0.34%. 4. The albumin material of a compact bone tissue is strengthened not only by small reinforcing elements, i.e., by the hydroxyapatite crystals, but also by formation of strengthened shells around the crystals. 5. On the basis of a study on the microdeformability of the organic and inorganic phases in the compact bone tissue of tibia and on the basis of an analysis of literature data a model is proposed for the deformation and rupture upon exposure to the loading type which is the most dangerous for a compact bone tissue, i.e., exposure to stretching.