Biological Materials Flashcards Preview

Biomechanics of Sports Injury > Biological Materials > Flashcards

Flashcards in Biological Materials Deck (20):

What are bones made up of?

Collagen (30% dry weight) - resist tensile loading
Minerals (70% dry weight) - resist compression


How much are bones capable to withstand compared to that of normal life?

6 times the amount


What are the two types of bones and which is stronger?

Cortical (outside) - strongest
Trabecular (inside)


What are the 2 different types of bone injury?

Traumatic - one-off
Fatigue Induced - stress related


What is Wolff's Law?

Bones form in the reaction to the forces placed upon it


What are the 5 types of bone fracture?

1) Diaphyseal Impaction - axial compression
2) Transverse - bending
3) Spiral - torsion
4) Oblique Transfer - axial and bending
5) Oblique - axial, bending and torsion


How are transverse fractures caused?

Bending loads
Combination of forces causes the break to occur - cracks at right angles


What are the different types of cartilage?

Structure-less (hyaline cartilage in knee)
Contain connective tissue (fibrocartilage in ribs)


What is the percentage of weight that the collagen fibrils take up in the organic matrix?

What material makes you spongy?


Proteoglycons suck up the water and make your joints spongy


What is anisotropic in relation to direction of loading?

If you apply force one way - the bones will respond the same way


How does cartilage show visoelastic behaviour?

- Moves slowly and returns back to normal
- When loading it deforms and then increases size again


What are the different types of articular cartilage injuries? (3)

What happens during avascular cartilage?

Avascular - where there is no blood supply, it repairs slowly and shows no external signs.

Overuse Injuries --> cartilage wears away
High Impact --> cartilage swells


What are the 6 types of deep connective tissue?

What role does it play in the body?

1) Tendons --> cords of packed collagen

2) Aponeuroses --> spread out to improve more activity for a single muscle

3) Deep Fascia --> envelop individual muscles and bind them into groups

4) Intramuscular Septa --> separates muscle groups passing from deep fascia to the bone

5) Ligaments --> similar to tendons and contains elastin

6) Ligamentous Joint Capsules --> guide motion and prevent excessive motion - goes around the bone


What is its failure strain?
Where is the main site for energy return during elastic recoil? (E.g.)


Achilles tendon - in basketball players its long but in rugby players its short


What is their purpose?
What is the role of mechanoreceptors?

To cope with tensile forces (tension)

Mechanoreceptors initiate tension in nearby muscles to assist in maintaining joint stability


What are other examples of injuries? (3)

1) Sprains --> caused by excessive joint motion
2) Direct Blows --> stretching and permanent deformation
3) Ligament Failure --> bending and torsion to the distal limb


What are the different types of ligament failure?

Mid Substance Tear @ fast loading rates
Bony Avulsion @ low load rates - where the ligament is stronger than the bone and just snaps off


What are the effects of muscle tears?

1) Loss of stability
2) Joint misalignment
3) Abnormal Contact pressures
4) Loss of proprioception


How far can muscles stretch past resting before they rupture?



How much more stiffness is an eccentric contraction more than concentric and why?

200x greater - the muscle always tries to shorten, so when a muscle is contracting eccentrically it still wants to shortern