M1-2 Class Notes 3

Question 1

What are the laws of spinal motion?

Answer 1

Fryette’s laws

Question 2

Fryette’s laws of spinal motion: Law 1

Answer 2

Side bend to the right is accompanied by rotation to the left

Question 3

Fryette’s laws of spinal motion: Law 1 applies to this type of motion in this part of the spine

Answer 3

• normal, neutral motion

- mostly lumbar spine

Question 4

Fryette’s laws of spinal motion: Law 1 does not apply to:

Answer 4

C-spine

Question 5

Fryette’s laws of spinal motion: Law 2

Answer 5

If facets are locked in full ext or flexion, R lateral flexion is accompanied by R rotation

Question 6

Fryette’s laws of spinal motion: Law 2

How is it different between lumbar and cervical?

Answer 6

R lateral flexion accompanied by R rotation

Normal for cervical spine in neutral

Question 7

Fryette’s laws of spinal motion: Law 3

Answer 7

The more motion you have in any one plane, the less you’ll have in any other plane

Question 8

Fryette’s laws of spinal motion: Law 1 is useful to know for these techniques

Answer 8

Manual

Question 9

Fryette’s laws of spinal motion: magnitude of secondary motion

Answer 9

SMALL

Question 10

Mechanisms of rotation: Initial rotation occurs about this axis

Answer 10

Central/posterior axis in vertebral body

Question 11

What structure interferes with rotation?

Answer 11

Facet joints

Question 12

What happens when you rotate to the left with respect to axis of rotation and overall motion between vertebrae?

Answer 12

• Only go a few degrees until R facets approximate
• On impact, motion stops and R facets become a “hinge”
• L facets open up like a door to allow more rotation

R facets are the new axis of rotation

Question 13

When facets open up like a hinge and axis of rotation changes, what other motions happen between the adjacent vertebrae?

Answer 13

Becomes gapped and distracted posteriorly

Question 14

Once the facets open up like a door on one side with rotation, what happens to other vertebrae?

Answer 14

• levels below rotate in a cascade
• rotation works its way down the vertebral column
• almost simultaneous

Question 15

What is a major component that limits rotational movement?

Answer 15

Synovial capsule on “door” side prevents over-rotation or excessive facet opening

Question 16

How much rotation do we have at each segment before the motion stops?

Answer 16

About 3˚

Question 17

What allows us to rotate more than just a few degrees?

Answer 17

Combined motion at multiple joints

Question 18

If a pt has OA on the R facet joint, they would likely be most painful with (R/L) rotation.

Answer 18

L

Not absolute, but helpful in thinking about mechanics

Question 19

According to Fryette’s law, L rotation would be accompanied by what movement?

Answer 19

R lateral flexion

Minimal, but it still happens

Question 20

Because lateral flexion occurs with rotation, what forces are exacerbated?

Answer 20

Forces on the R facet joint

Question 21

With sufficient loading, you can get this (with respect to facets)

Answer 21

• bony impaction between edges of facets on top and bottom segments
• can be a source of pain

Question 22

Anterior translation of the vertebra during flexion is limited by what structure(s)?

Answer 22

• facet joints

- ALL

Question 23

Facet activity with anterior translation

Answer 23

• loaded during flexion

- slide upward a bit

Question 24

IVF volume and flexion

Answer 24

Increases

Question 25

Facets stop excessive anterior translation during flexion to protect this

Answer 25

Central canal

Question 26

When the L-spine is flexed, body weight exerts these forces on the IV joints

Answer 26

• compressive

- shear

Question 27

Magnitude of forces on the IV joints is proportional to this

Answer 27

Angle of inclination of the interbody joint

Question 28

Dogs: this is normal

Answer 28

Scotty dog

Question 29

Dogs: Scotty dog with a collar

Answer 29

• Spondylolysis

- could be a stress fx or true fx

Question 30

Dogs: Decapitated Scotty dog

Answer 30

• Spondylolisthesis

- head moves away from the body

Question 31

This view of radiograph is used to asses effect of Scotty dog

Answer 31

Lateral