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How to read a C-spine film
While emergency physicians are increasingly utilizing C-spine CT (especially in high-risk patients and those already getting a head CT), familiarity with the reading of the cervical spine x-ray is a skill that falls solidly within the scope of the ED physician. Below we will review the ten steps to reading a c-spine xray. One way to remember these steps is AAABBBCs.
- make sure that you can visualize the entire C spine to the C7-T1 interface
-***failure to visualize the seventh cervical vertebra and the CT/TI junction is the most common error made in the radiographic assessment of cervical spine injury
-make sure there is no rotation present (rotation will be seen when left and right diamond-shaped lateral masses of each vertebra are not superimposed as below)
-Make sure the the anterior longitudinal ligament line (also anterior vertebral line), posterior longitudinal ligament line (also posterior vertebral line), spinolaminar line and tips of spinous processes fall along a smooth and continuous line.
Emergency Medicine a Comprehensive Study Guide, 6th edition, 2004. Mc-Graw-Hill.
- make sure the anterior atlantodental interval (also called pre-dental space) is less then 3 mm in adults and less than 5 mm in children
http://www.emedhome.com/features_archive_detail.cfm?SFID=080403&SFTID=news
-make sure the basion-dens interspace is less than 12 mm (see examples below of a normal and abnormal BDI)
http://www.emedhome.com/features_archive_detail.cfm?SFID=080403&SFTID=news
-make sure the ring of C2 is smooth and continous
Check for a "fat C2"
- Inspect each bone (vertebral body, pedicle, articular mass, lamina, spinous process) from top to bottom
- *** the majority of missed fractures are at the upper and lower cervical segments
Emergency Radiology, 1st edition, 2000. McGraw-Hill
- check for uniform disk spaces between vertebrae
- make sure that the space between opposing facets is parallel and that joint space is uniform
- make sure that the pre-vertebral tissue is within the expected size range
- 6 mm at C2
- 22 mm at C6
- Or above C4: soft tissues less than 50% of the width of a vertebral body
- below C4 the limit is one full vertebral body width.
- Briefly view base of skull, mandibles, anterior neck
- Also evaluate sinuses, occiput, mandible
- Airway: epiglottis, hyoid bone, tracheal air shadow
- Finally, check for foreign bodies
Same system for open mouth view
- Adequacy/alignment: no overlap by teeth or skull base, dens, spinous process, lateral masses are all symmetrically aligned
- Bones: base of dens, body of C2, C1 lateral masses
- Cartilage: articular spaces between C1 and C2 are even and the image that's now there.
Same system for AP films
- Adequacy/alignment: spinous processes midline and evenly spaced
- Bones: vertebral bodies, uncinate processes, lateral masses, spinous processes
- Cartilage: disk spaces uniform in height to the end
Emergency Radiology, 1st edition, 2000. McGraw-Hill
