Load and Deformation Relationships / Fractures Flashcards
T/F: Stress and load are the same thing.
True
What is a strain?
A change in shape (deformation) that takes place in a tissue
What is elastic tissue?
Tissue that can be deformed but returns to its original shape when the load is removed
What is plastic tissue?
- Tissue that structurally changes when a force is applied to it
- It can’t return to its original shape after
What is the yield point of a tissue?
- The point at which a tissue starts to deform and change shape
- Elastic properties are lost and it becomes plastic
What is the ultimate stress / fail point of a tissue?
- The point where the tissue can’t handle any more stress
- This tissue breaks
What does the amount of tissue deformation depend on?
- The type of stress
- The direction of the stress
- The time under stress
What does it mean for a tissue to be anisotropic?
A principle that states that the amount of strain and deformation of a tissue DEPENDS ON the direction of the force
What are deformations of the human skeleton called?
Breaks or fractures
What is a repetitive load? What happens if you get too much?
- Repeated application of a subacute force
- Usually low magnitude
- A chronic, overuse, or stress injury
What is an acute load? What happens if you get too much?
- Application of a single force that is sufficient enough to cause injury to a biological tissue
- The tissue is brought to the failure point in one movement
- Think: trauma
- A fracture
What is a fracture?
- A disruption of the continuity of bone
- Type depends upon the direction, rate, magnitude of loading stress
What is a stress fracture? Why does it happen?
- Small disruption of continuity of outer bone
- There are repeated forces in low magnitude and the individual does not allow time for complete remodeling to take place in the area of weakened bone - osteoclasts outweigh osteoblasts
What are sprains?
Plastic stretching or deformation of ligaments
