Abstract
The cortical bone is a hierarchically organised biocomposite tissue ranging from the nanoscopic to the macroscopic scale. The present paper is concerned with the new morphological observations of human femoral cortical bone at the nanostructural/submicrostructural levels of older patients.
The objective of this study is to verify and refine the descriptions of nanostructures and submicrostructures in selected localities of the human femoral diaphyses by the scanning electron microscope - Quanta 450 with the ETD detector. The great interest has been focused on identifying the orientations of basic structural domains of bones at each of their structural levels.
The bearing structural domains are composed and oriented not only to effectively resist localized mechanical stresses/strains, but to promote uniform dissipations of energy of deformation into lower structural levels of tissue. As the domains of the 2nd structural level are mineralized nanofibrils, then dominant domains of the 3rd structural level are layered nanoshalls, creating the mineralized cylindrical columns, i.e. mineralized microfibres.
Each mineralized nanoshell is composed of parallel oriented mineralized nanofibrils (nanorods). The nano/substructural elements are formed (during the bone remodeling) under the influence of the dominant biomechanical effects as are torsional micromoments, microforces in tension and/or in compression.