veterinary Osteology (Animal)

          Osteology                                                                      

Bone Classification Schemes

Development:

Endochondral bones — Develop from cartilage precursors.

     

Intramembranous bones — Directly from mesenchyme.

   

Location:

Axial skeleton — Head, vertebral column ( including tail),

 ribs & sternum

Appendicular skeleton — Bones of limbs, including

        scapula & os coxae(hip bone)

Heterotopic bones —  os penis (carnivore; rodent)

    os cardis (cattle)

Shape:

Long bones — length greater than diameter

Short bones — approximately equivalent dimensions

Flat bones — e.g., scapula, os coxae, many bones of skull

Irregular bones — short & multiple processes (vertebrae)

Sesamoid bones — small “seed-like” within tendons,

       e.g.,  patella (knee cap)

                  

Mechanical Considerations

Strength = amount of strain a bone can withstand without             breaking. Bone is best at withstanding compression, especially against the grain.

Tensile strength = 1/2 of compression, comparable to tendons & ligaments.

Shear strength = 1/4 of compression, most fracture are the result of shear forces.

General Principle:

Bones are designed to provide adequate strength with minimal material. Such an economy of bone mass/weight

offers evolutionary advantages, faster reaction capability, reduced metabolic requirements

Scapula strengthened with only a spine

Sesamoid bone — Patella

1. Eliminates tendon shear

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2. Redirects lines of force

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3. Increases Torque

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