Skeletal Properties

Bone: We have seen before that bone is uniquely structured to be lightweight and strong at the same time. This purposeful construction to efficiency is evident the more we look into it. Biomechanically, bone is akin to a biphasic composite structure, of organic and inorganic phases. Organic component gives it flexibility and the inroganic component provides rigidity. The composite structure is far stronger than the original constituents alone. Microscopically bone is composed of cortical and cancellous bone. Cortical bone is stiffer than cancellous bone. 

Bone being viscoelastic shows loading rate sensitivity and becomes stiffer, stronger and more brittle at higher loading rates. Bone responds to load by deformation. This ability depends on its ability to store energy. Older bone has low ductility, is less able to store energy than a young one and fails at a lower level of load. 

Low energy loading results in clean cut fracture. High energy loading results in comminuted fracture.

Muscle contraction is important to regulate bone loading. They can neutralise tensile load and allow bone to carry increased load. Fatigue failure can result from muscle weakness. 

Bone behaviour is also influenced by its geometry. Bone response to bending and torsion follows the same principle, so distribution of bone mass away from the neutral axis is helpful. This is why long bones are tubular in shape. Bending moment is also influenced by its length. The longer a bone, the more its bending moment and resultant stress. 

A long bone can act as a column, supporting compressive load along its long axis. or as a shaft, to resist torsion or as a beam , resisting bending moments. Tibia acts as a column to support body weight , neck of femur resists bending moments. When the foot is twisted, tibia resists torsion. 

Bone structure is dissimilar in longitudinal and transverse directions, this results in anisotropic behaviour. 

Bone behaves differently under different loading conditions. It is stronger in compression than tension than shear. Different types of loading also produces different types of fracture.

Please log in to view the content of this page.
If you are having problems logging in, please refer to the login help page.

© 2011 Website by Regency Medical Marketing 
Biomet supporting orthoteersOrthoteers is a non-profit educational resource. Click here for more details
Joint Lubrication
Patello-femoral joint
Shoulder Stability 1
Shoulder Stability 2
Skeletal Properties
Orthoteers biomechanics Advertise on Orthoteers
Orthoteers Junior Orthoteers Orthopaedic Biomechanics Orthopaedic World Literature Society Educational Resources Image Gallery About Orthoteers Orthoteers Members search
Hide Menu