Vertebral Column Function

Question 1

passive stability

Answer 1

only reliant on the bones + soft tissues

Question 2

what resists compression

Answer 2

vertebral bodies + discs

Question 3

compression of spinal cord

Answer 3

forces directed down through the spinal column

Question 4

what do longitudinal ligaments do

Answer 4

reinforce disc front + back

Question 5

zygapophysial joints resist

Answer 5

compressive/axial load through the spinal cord

Question 6

describe zygapophyseal joints in extension

Answer 6

bear about 30-40% of compressive load that happens through the vertebral column

Question 7

where are discs strongest

Answer 7

centrally, in the middle

Question 8

how do discs resist compression

Answer 8

predominantly water in the nucleus thus resists compression
-water has a great resistance to compressive load particualrly at high velocity

Question 9

disc- deformation in all directions

Answer 9

water pushes back in all directions against a load- this will stabilize the annula

Question 10

what part of the disc is first to fail under high/rapid loading

Answer 10

end-plates

Question 11

discs in which part of the spinal cord have less water

Answer 11

cervical discs
-have less water + therefore respond slightly differently

Question 12

example of symmetrical loading of the disc

Answer 12

-large arrow downwards: gravity or compressive load
-small arrows in every direction: water within the nucleus is pushing back in all directions to cause tension in annulus fibrosis

Question 13

example of asymmetrical loading of the disc

Answer 13

-disc compression of someone bending/moving to the right
-nucleus can’t move but there will be increased forces/tension pushing out to the left annulus fibrosis

Question 14

distraction

Answer 14

tensile/stretching forces

Question 15

describe distraction to discs

Answer 15

can occur symmetrically (2 vertebral bodies are separated from each other) OR
can happen when we are moving

Question 16

____ resists tensile loads

Answer 16

annulus
-tensile loads are absorbed by the annulus

Question 17

bands of the annulus are strongest where

Answer 17

anteriorly + posteriorly
-movement in the sagittal plane (flex/extend)

Question 18

if distraction is occuring on L side of disc, what is happening to the R

Answer 18

compression

Question 19

shearing (translation) does what

Answer 19

causes stretching in annulus

Question 20

____ resists shearing stress as tensile

Answer 20

annulus

Question 21

distraction + other tensile forces are resisted by ____

Answer 21

annulus

Question 22

alternating bands of annulus have

Answer 22

fibers running in opposite directions
-under torsion, only 1 set of those bands are actually under torsion

Question 23

why are you told not to twist

Answer 23

because you are only getting 1/2 of support from annulus

Question 24

torsion is resisted by ____

Answer 24

resisted by one set of fiber rings in annulus
-not all bands are working

Question 25

superior part of zygophophyseal joint

Answer 25

inferior zygophophyseal joint facets of the superior vertebrae

Question 26

inferior part of zygopophyseal joint

Answer 26

superior zygophohyseal joint facets of the inferior vertebrae