| A | B |
|---|
| function of skeleton | to protect internal organs, allow for locomotion, provide stability, site for red blood cell production |
| characteristics of bone | high strength to weight ration, self-repairing |
| axial skeleton | head, spinal cord, trunk, pelvis. main axis of body about 80 bones |
| appendicular skeleton | upper and lower limbs about 126 bones |
| cortical bone | hard stabilizing structure, protective covering, contain nutrient pathways |
| trabecular bone | porous/cancellous bone, contains trabeculae (metabolic processes) |
| physical properties of bone | structural and mechanical properties of bone change with the forces acting on the bone. wolff's law of adaption |
| wollf's law of adaption | stress has different effects on bones. stress can effect growth, modeling and/or remodeling. growth of bone is influenced by heredity. type of loading influences bone formation and/or remodeling (dynamic loading better than static) |
| bone anisotropy | bone is a non-homogenous and anistropic material. mechanical properties change as function of the locatoin of the applied force. stiffness in tension is max for axial forces and minimal for perpendicular forces. stiffness for axial forces is roughly 2X the magnitude for perpendicular forces. bone stress/strain capacity related to osteon stress/strain |
| strain mode | both compression and tension provide stimuli for bone formation. greatest bone density often appears in the compression of the cortex of bone |
| strain direction | osteons oriented in principle loading direction for compression and tension |
| strain rate | important parameter in bone's response to load and strain. bone responds differently to static and dynamic loading. bone formation occurs as a result of intermittent (alternating static and dynamic) load |
| strain frequency | repetitive bone strain promotes net bone formation. |
| strain distribution | strain stimulus required to effect net bone formation depends on pattern of loading. necessary strain stimulus lower for unusual patterns of loading |
| strain energy | is product of stress and strain. thought to be important in increasing bone density |
| bone fracture may occur as result of.. | excessive stress (external force to excessive, dimensions of bone are small, geometry of external force is unfavorable,excessive frequency of load application) or bc of weak material |
