A Brief Deck on The Science of Fractures

Question 1

How do fractures occur?

Answer 1

when the physical force exerted on a bone is stronger than the bone itself

Question 2

Where do proximal fractures occur and where do distal fractures occur?

Answer 2

Proximal Fracture: Occurs closer to the center of the body. For example, a proximal humerus fracture is near the shoulder.
Distal Fracture: Occurs further away from the center of the body. For example, a distal radius fracture is near the wrist.

Question 3

What are the causes of dislocation (of the parts of the fractured bone)?

Answer 3

Trauma: can push bones out of their joints
Falls: landing awkwardly can lead to dislocation especially in the shoulder or elbow
MUSCLE PULL (used in questions to answer the direction of dislocation)

Question 4

What do you look at to determine the direction of dislocation?

Answer 4

1. Identify the muscles attached to the bone segments near the fracture site.
2. Understand the normal function of these muscles—which way they pull the bone during contraction.
3. Consider the position of the limb at the time of injury—muscles on one side may be contracted more than the other.
4. Assess the fracture type—some fractures are more likely to dislocate in a particular direction due to the muscle attachments and the line of force causing the fracture. THE POSITION OF THE FRACTURE WILL BE IMPORTANT TOO.

Question 5

If more than one muscle is involved in dislocation of bone during a fracture, how do you know which muscle will override the others in terms of dislocation?

Answer 5

• primary actions of muscles (vector forces here, this is where maths and physics come in)
• number of heads at attachment
• anatomical position of muscles
• muscle contraction