What is pressure?
- The amount of force distributed over a given area
- The more surface area, the more distribution of the weight and pressure
- Pressure = force / area
What is stress?
- Distribution of force within a body
- Stress = force / area
- Can be used interchangeably with load
What is load?
Any force applied to an object or person
What are the five types of loads?
- Compression
- Tension
- Bending
- Shear
- Torsion
What is a compression force? What is an example when talking about the body?
- When the ends are pressed together
- Results in widening and shortening of the object / bones
- The weight of the body compresses the cartilage in between the femur and tibia
What is a tension force? What is an example when talking about the body?
- Pulling or stretching
- Results in narrowing and lengthening of the object / bones
- Stretching
What is a bending force?
Creating compression on 2 sides and tension on a third side
What is a shear force?
- Forces applied parallel to the surface in between
- Causes rubbing of the objects / bones horizontally
What is a torsion force? What is an example when talking about the body?
- Twisting / rotation
- One end of a bone is fixed while the other is rotating on it
What happens to a bone if too much compression is applied to it?
A compression fracture
What happens to a bone if too much tension is applied to it?
An evulsion fracture
What happens to a bone if too many bending forces are applied to it?
- A ski-boot fracture would be an example
- May result in open fractures
What happens to a bone if too many shear forces are applied to it?
Grinding of bones
What happens to a bone if too much torsion is applied to it?
Spiral fracture
