Bone bio-mechanics and forces

Question 1

Describe Tension force

Answer 1

Consists of 2 pulling forces

Question 2

Describe compression force

Answer 2

consists of 2 pushing forces

Question 3

Describe shear force

Answer 3

consists of 2 equal and opposite forces acting parallel that tend to displaced an object between the lines of force

Question 4

Describe rotation force

Answer 4

is a twist that affects one end with the other end fixed

Question 5

Describe bending force

Answer 5

places maximum tension on the convex surface and maximum compression on the concave surface of a bent object

Question 6

What type of fracture does tension loading cause

Answer 6

Transverse fracture

Question 7

What type of fracture does compression loading cause

Answer 7

Oblique fracture

Question 8

What type of fracture does rotation loading cause

Answer 8

Spiral fracture

Question 9

What type of fracture does bending cause

Answer 9

butterfly fragment fracture

Question 10

Describe splints and casts

Answer 10

• immobilize fracture
• do not directly contact bone
• rigid material

Question 11

Describe external fixation fracture repair

Answer 11

• used on complex fractures
• used where there is high risk of infection
• increase rigidity by increasing number of pins
• infinite variations of set up to suit range of needs

Question 12

What do plate and screws do

Answer 12

Screws- apply friction between plate and bone and apply compression between fragments
- plate - hold fractured parts in alignment and allows compression between fracture ends and load transfer

Question 13

Describe intramedullary rods

Answer 13

little resistance to axial compression or torsion

resist bending forces

Question 14

What is Wolff’s law

Answer 14

states that your bones will adapt based on the stress or demands placed on them.

Question 15

What is bone remodelling?

Answer 15

is a continuous process, with bone resorption and formation occurring at the same time.
Remodelling occurs in response to mechanical stress