C-spine x-ray interpretation

Cite this article as:
Partyka, C. C-spine x-ray interpretation, Don't Forget the Bubbles, 2017. Available at:

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. 

The C7/T1 junction must be visible

A: Alignment. 

Ensure all 4 lines are contiguous/uninterrupted
1. Anterior longitudinal line
2. Posterior longitudinal line
3. Spinolaminal line
4. Spinous process line

B: Bones. 

Each vertebrae must be examined for fracture/collapse/avulsion.

Parallel facet joints.

C: Cartilage (aka. disc spaces). 

Examine for symmetry/normality of the intervertebral discs between each vertebrae

S: Soft tissue.
Prevertebral swelling of <2/3 of adjacent vertebral width


  • <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

rom Emergency Radiology: Case Studies via accessemergencymedicine.com

  • 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.

from Hippoed.com

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.

Case courtesy of Gerry Gardner, Radiopaedia.org, rID: 13990


Odontoid fracture (types II & III)

Specifically, types II & III.

Case courtesy of Dr Mohammad Taghi Niknejad, Radiopaedia.org, rID: 21310

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.

Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID: 32185

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.

from clinicalgate.com



Author: Chris Partyka Dr Chris Partyka is an advanced trainee in Emergency Medicine working at Liverpool Hospital, NSW. Chris is one of the rare ED docs with an Australian accent! He has a keen interest in medical education, ultrasound & coffee. He also authors thebluntdissection blog & tries to out-smart his paediatric patient's with a sound knowledge of cartoons.

10 Responses to "C-spine x-ray interpretation"

  1. Gerry GArdner
    Gerry GArdner 2 years ago .Reply

    Nice images! However a further magnifying option would be useful for some of the images even when they are at full size..

  2. Mario Stefano
    Mario Stefano 2 years ago .Reply

    A very helpful webpage Dr Chris. I hope I never find or miss any of these nasty presentations in practice.

  3. Sergio Kerr
    Sergio Kerr 2 years ago .Reply

    Excellent! Very clear and concise. Really enjoyed it!

  4. zainab adam
    zainab adam 2 years ago .Reply

    excellent stuff

  5. Dr Azim
    Dr Azim 1 year ago .Reply

    Very very well explained

  6. maysa malih
    maysa malih 1 year ago .Reply

    very nice and very well received . thanks

  7. Ugwu Nneoma
    Ugwu Nneoma 1 year ago .Reply

    Thanks!! Very concise!!

  8. Ben Powell
    Ben Powell 1 year ago .Reply

    This is great, particularly like the way pseudosubluxation is explained.

  9. Nelly Aika
    Nelly Aika 1 year ago .Reply

    Very informative and easy to understand.

  10. Jay
    Jay 1 year ago .Reply

    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?

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