BM_N5

• 1) Articular - Lines joins and provides bearing surface.
• 2) Elastic - Ribs
• 3) Fibro - Provides shape and stiffness (ears)

The cartilage is filed with MPS which have negative points where water can weakly bind. This makes a hydrogel (Synovial fluid) which behaves elastically under fast loading and flows under slow loading (Thixotrophy).

• 1) Collagen for tensile loading with
• 2) discrete nano-sized Hydroxapetite for compression and crack propagation prevention.

• 1)Enamel (95% Mineral) Hard and brittle
• 2)Dentin (Bone without cells)
• 3)Pulp (Nerves and blood supply)

• Plate bones - Pelvis, skull, shoulder blade, sternum
• Long bones - Femur, tibula
• Specialize - ear

• Long bones are made up of
• i) Cancellous (Spongy) bone
• ii) Cortical (Compact) bone

The amount of mineralization in bone has a large effect on its properties.

Both stiffness and strength increase with increasing mineralization, but toughness has a maximum around 67%.

• Longitudinal - Highest stiffness and toughness
• Transverse - Medium stiffness and toughness
• Radial - Lowest stiffness and toughness

**Attributes are best along osteon axis and worst across osteon axis.

As the loading rate increases the bone becomes brittle and plastically deforms less before fracture.

The structure of a bone reflects the load placed on it. If load changes bone will remodel.

• Synovial - Move allot and have a cavity (knee, hip)
• Synarthrosis - No cavity and move little (Skull)

• 1) Bone cement - Fast, bone necrosis
• 2) Porous ingrowth coating - Takes a long time, hard to remove

• 1)Von-Misses - Not good for brittle material.
• 2)Strain energy density - Good for bone