FACET JOINT DISLOCATIONS

Question 1

What is a transverse atlantal ligament rupture ?

Answer 1

This is the rupture of the transverse longitudinal ligament which holds the dens against the anterior aspect of C1.

Question 2

How can you tell a transverse longitudinal ligament rupture from an Xray ?

Answer 2

The transverse longitudinal ligament will increase more than 3mm.

Question 3

Why is a transverse atlantal ligament rupture an emergency?

Answer 3

As the spinal chord becomes compressed when the odontoid gets displaced posteriorly.

Question 4

Why does this require surgery ?

Answer 4

It is an unstable injury . Ligaments don’t heal they need to be fused.

Question 5

Why is the transverse ligament important ?

Answer 5

It holds the dens against the anterior aspect of C1. This maintains the space available for the chord.

Question 6

What is the difference between a unilateral and bilateral facet joint dislocation ?

Answer 6

In unilateral facet joint dislocation the dislocation is 50 percent less than the cervical body width.
In bilateral facet joint dislocation the dislocation is 50 percent greater than the cervical body width.

Question 7

What are 2 xray features of a unilateral facet joint dislocation ?

Answer 7

1 There will be rotation from a lateral position at the level of the dislocation. (image will look unorganised).
2 There will be less than 50 percent slippage of one vertebrae on another.

Question 8

What are the Xray features on a bilateral facet joint dislocation ?

Answer 8

1. The image will appear lateral with no evidence of rotation.
2. There will be a larger than 50 percent slippage of one vertebrae on another.

Question 9

What are bilateral facet joint dislocations also known as ?

Answer 9

Perched facets