The complex biomechanics and morphology of the femur proximal epiphysis are presented. This specific region in human femur is characterized by a high flexibility compared to that of other primates, since evolved lighter and longer due to the human verticalposition and more balanced loading. The nature and fine morphology of the femur head and its structural behavior have been investigated. Isotropic and orthotropic trabecular structures, which are not present in other primates, have been associated to compression and tensioned areas of the femur head. These isotropic/orthotropic trabecularmorphologies and allocationsgovern the stress and strains distribution in the overall proximal femur region. Useof femur proper biofidel modeling while enabling the explanationof physiological stress distribution elucidates the critical mechanical role of the trabecular bone that should be accounted in the design new innovative more "biologic" prosthetic system.