Normal Bone Structure

Normal Bone Structure

1. Three types of bones

   • Long
     • Morphology
       • Circular cross section
       • Thick walls
       • Hollow midsection
     • Parts of long bones
       • Epiphysis, Metaphysis, Diaphysis
       • Apophysis
         • Traction
         • does not transmit weight
     • Functions
       • Levers
       • Carry compressive and bending loads
   • Short
     • Morphology
       • Thin cortices
       • Filled with Trab bone
     • Function
       • Compressive load, short distances
   • Flat
     • Morphology
       • Broad surfaces
       • Two sheets of cortical bone sep by trab bone
     • Function
       • Protection

2. Two types of bone

   • Trabecular
     • rapid turnover, high porosity
     • Function
       • mineral homeostasis, support
   • Compact (cortical)
     • slow turnover, low porosity
     • Function
       • biomechanical, supportive

3. Inside and outside

   • Periosteum
     • fibrous tissue
     • inner cellular layer
       • Sharpay's fibers anchor periosteum to bone
     • NOT on articulating surfaces
   • Endosteum
     • single layer of BLC along surface of bone
     • Lines inner cortex
   • Marrow
     • Network of BVs and sinusoids
     • Maturing blood cells
       • Red
     • Yellow = fat
       • Diaphysis
   • Bone matrix
     • 90% collagen type I
     • Mineral: HA
     • water, lipids

4. Two organizations of bone

   • Woven
     • Temporary, disorganized, rapidly formed
   • Lamellar
     • Organized, slow formation, strong

5. Blood supply

   • Haversian systems (osteons)
     • veins, arteries, nerves
     • Connected by Volkmann's canals
   • Diaphysis
     • Nutrient foramen
   • Epiphysis
     • small foramen
   • Cortex
     • Periosteal vessels