In modern bone biomechanics the bone tissue is treated as a porous elastically deformed solid filled with a viscous newtonian fluid (two-phase poroelastic model) [41]. Traditional one-phase biomechanical model of bone tissue is still valid and it can be considered as an approximate model in comparison with the more realistic two-phase model of bone tissue. Hierarchical biostructure of the pore space of cortical and trabecular bone is presented, including the compartments of bone pore space after Cowin [12, 13]. Examples of clinical amplications of the poroelastic model of bone tissue such as: osteoporosis, porous coated implants, bone electromagnetostimulation in rehabilitation are indicated.