Bone biomechanics and forces SDL (NMSK)

•what forces act on a bone?

upwards from the floor

downwards from the horse’s weight

What factors effect how bone responds when a force is applied?

microfractures

stiffness

thickness of bone + bone density

characteristics of force

material properties of bone

geometry of bone

what force is applied to these

Describe how forces such as bending, rotation, compression, tension, shear will influence the bone microstructure

microfractures = weaker bone (woven)

more likely to break

repeated stress = worse

Is the microstructure of bone static or dynamic? 

dynamic

What Law describes the behaviour of bone?

wolff’s law

is bone flexible

no

is bone malleable

no

Does a long bone have the same

Properties throughout its structure?

no

bone fatigue - how does it occur

microfractures break the laminar bone and cause woven bone to form.

woven bone is irregular and more fragile

repetitive stress = more woven bone and a weaker overall bone.

more likely to have catastrophic break

stress against strain graph positive correlation

bone strain

% compression of the bone

List some clinical signs of stress fractures and which imaging tools you would use to confirm your findings.

X ray

weakened performance of animal

What happens if bone resorption is excessive and there is reduced formation of bone?

decrease bone Ca which means decreased bone density and so bone is weaker lead to catastrophic break