The ABC’s of the cervical spine provide a helpful mnemonic to guide the systematic assessment of these x-rays. Remember; you require all three views (lateral, AP and odontoid/open mouth view) for an adequate study.
A: Adequacy.Â
The C7/T1 junction must be visible
A: Alignment.Â
Ensure all 4 lines are contiguous/uninterrupted
1. Anterior longitudinal line
2. Posterior longitudinal line
3. Spinolaminal line
4. Spinous process line
B: Bones.Â
Each vertebrae must be examined for fracture/collapse/avulsion.
Parallel facet joints.
C: Cartilage (aka. disc spaces).Â
Examine for symmetry/normality of the intervertebral discs between each vertebrae
S: Soft tissue.
Prevertebral swelling of <2/3 of adjacent vertebral width
Alternatively:
- <7 mm anterior to C2
- <2 cm anterior to C7
Spaces & lines (see examples below):
from Slack SE, Clancy MJ Clearing the cervical spine of paediatric trauma patients Emergency Medicine Journal 2004;21:189-193.
Pre-dental space
- Normal <3 mm
- >3 mm (XR) or 2 mm (CT) ?damage to transverse ligament
- >5 mm implies rupture of transverse ligament
Basion-dental interval
A marker of occipito-atlantial dissociation
from Chris Partyka
Should be:
- <12 mm on x-ray or
- ≤8.5 mm on CT
Line of Swischuk
Helps differentiate pathological anterior displacement of the cervical spine (typically C2/3) from physiological displacement, termed pseudosubluxation.
A line is drawn between the anterior aspect of C1 & C3 spinous processes.
Dr Jeremy Jones, Radiopaedia.org, rID: 43445.
The anterior aspect of C2 spinous process should be within 2 mm of this line.
Deviation >2 mm: indicative of true subluxation.
Deviated <2 mm: consistent with pseudosubluxation
from Slack SE, Clancy MJ Clearing the cervical spine of paediatric trauma patients Emergency Medicine Journal 2004;21:189-193.
A: No subluxation. Therefore, posterior cervical line (PCL) cannot be applied. Anterior aspect of spinous process of C2 commonly misses PCL by 2 mm.
B: Subluxation is present. The anterior aspect of spinous process of C2 misses the PCL >2 mm. Finding is suggestive of a hangman’s fracture of the neural arches of C2.
C: Pseudosubluxation is present. The anterior aspect of spinous process of C2 touches or lies within 2 mm of PCL.
Take at this very early post from Loren Yamamoto too.
Now we’ve seen what’s normal, let’s consider the potential injuries using the mnemonic – Jefferson Bit Off A Hangman’s Thumb.
Jefferson fracture
Burst fracture of C1.
Bilateral facet dislocation
A flexion distraction type of dislocation of the C-spine, often a result of buckling force.
Odontoid fracture (types II & III)
Specifically, types II & III.
Atlanto-occipital dislocations
Severe injuries including both atlanto-occipital dislocations and atlanto-occipital subluxations.
Hangman fracture
Bilateral lamina and pedicle fracture at C2 with anterolisthesis of C2 on C3. Associated with judicial hangings.
Tear drop fracture (extension)
Typically resulting in an avulsion of the anteroinferior corner of the vertebral body.
Often associated with central cord syndrome.
Denis’ columns.
Any injury involving two or more of Denis’ columns are considered unstable. One of the more extreme examples of this is the ‘Chance fracture’, a flexion-distraction injury.
Crush fractures.
An anterior crush fracture of >50% loss of height in the thoracolumbar spine or >25% of the cervical spine is considered unstable.
Emergency medicine Arabic board
Nice… 5 stars
Is this site still up & running? I noticed everything is from 2yrs ago?! :/
We’ve been going since 2013 and are still posting 3 times a week, Mindy.
Take a look at the home page.
hi great presentation Chris, But I was wondering what you referred to as a “one of the rare ED docs with an Australian accent!” about your self?
Very informative and easy to understand.
This is great, particularly like the way pseudosubluxation is explained.
Thanks!! Very concise!!
very nice and very well received . thanks
Very very well explained
excellent stuff
Excellent! Very clear and concise. Really enjoyed it!
A very helpful webpage Dr Chris. I hope I never find or miss any of these nasty presentations in practice.
Nice images! However a further magnifying option would be useful for some of the images even when they are at full size..