0:00

With our craniovertebral junction injuries,

0:04

we really should look at the MRI scan to look for

0:10

the integrity of the ligamentous complex.

0:14

This was an individual who had a fracture

0:17

of the anterior arch of C1.

0:20

And you can see the two bone fragments that are displaced

0:24

from one another at the anterior arch of C1.

0:27

On the scans, we generally focus on the STIR imaging.

0:33

The STIR imaging is the one with obviously the fat suppression.

0:37

It's particularly nice for demonstrating ligamentous

0:40

injury at all parts of the spinal column.

0:43

In this case,

0:44

what we are able to see is that the patient has high

0:49

signal intensity, which is behind the longus colli,

0:55

longus capitis muscle complex,

0:56

which is seen here as this darker signal intensity.

1:00

Now, on the sagittal scan,

1:02

it's sometimes difficult to distinguish between the

1:06

anterior longitudinal ligament, which is seen here,

1:09

and the adjacent musculature,

1:12

which is also dark on a T2-weighted scan.

1:14

So we'll look at the axial scan to better evaluate that.

1:19

In this case, as we look at the anterior longitudinal ligament,

1:24

we see that there is a gap there at the location

1:27

where the fracture has occurred.

1:30

The next thing to look for is the extension of the posterior

1:34

longitudinal ligament from the lower cervical spine

1:39

superiorly onto the tectorial membrane,

1:42

communicating with the back of the clivus.

1:46

So here's our clivus,

1:47

and that actually looks like it is intact.

1:51

Be careful that you're in the midline.

1:53

As you go off midline,

1:54

you will see that the posterior longitudinal ligament

1:59

and tectorial membrane becomes out of plane.

2:04

So if we follow this off to one side,

2:07

we see dark signal intensity of the posterior longitudinal

2:10

ligament to the tectorial membrane.

2:12

And then as we go on the contralateral side,

2:15

you see a discontinuity in that ligament.

2:19

And that would suggest that there is indeed rupture

2:22

of the tectorial membrane just to the, in this case,

2:26

to the right or left of midline.

2:29

The other ligament that we want to look for is a small black

2:32

ligament that attaches from the odontoid process

2:35

to the under surface of the clivus.

2:39

And it's sort of a vertically oriented apical ligament.

2:44

And in this case, once again,

2:46

we see that there is discontinuity of the

2:49

apical ligament on the sagittal image,

2:53

we're not seeing that little dark line that connects

2:56

the inferior clivus to the top of the

3:00

odontoid process, and instead we have bright signal intensity.

3:03

So this is not compromising the spinal cord.

3:07

We don't see a large epidural hematoma,

3:09

but we do see all these findings on the sagittal scan.

3:13

Let's bring up the axial T2-weighted scan.

3:18

And here we have our longus colli musculature.

3:22

Here we have the clivus,

3:23

and we're going to continue inferiorly.

3:25

And we note that this bright signal intensity

3:29

is not in the retropharyngeal space.

3:31

The bright signal intensity is behind the musculature and

3:36

therefore in the prevertebral space where you should

3:40

not see edema, and this is secondary to the trauma.

3:44

So here is this bright signal intensity. Here's

3:47

the longus musculature.

3:49

And here is, what we're seeing here is this prevertebral

3:53

high signal intensity behind the muscle right here.

3:58

Now we're looking at the ligamentous complex,

4:01

which is the anterior longitudinal ligament,

4:03

which runs anteriorly here.

4:05

And this is where we see that discontinuity right here,

4:09

with the bright signal intensity extending right to

4:12

the portion of the odontoid process, right here.

4:16

Looking at the posterior longitudinal

4:18

ligament, behind on the axial scans,

4:22

we see the appearance here of the ligament off midline,

4:28

but on the right side, it's actually bright and

4:31

signal intensity. So on the axial scans,

4:35

what we see is the discontinuity on the right side of that

4:42

tectorial membrane junction with the posterior longitudinal

4:45

ligament seen on the sagittal scan and

4:48

then reproduced on the axial scan.

4:51

So we have ligamentous disruption both in the anterior

4:55

longitudinal ligament as well as the tectorial membrane,

4:58

as well as the apical ligament associated

5:00

with this anterior arch of C1 fracture.