7/24/2019 C1 C2 Fractures

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C1 and C2 fracturesLin M and Mahadevan S. Spine and Spinal Cord Injuries in Adams J et al (eds),

Emergency Medicine. New York: Elsevier, 2007.

Injury(mechanism)

Stable Comment

Atlanto-occipitaldislocation(flexion)

No * Often instantly fatal* More common in children because of small,

horizontally-oriented occipital condyles* Dislocation can be anterior (most common), superiorly

distracted, or posterior

Anterioratlantoaxialdislocation(flexion)

No * Associated with transverse ligament rupture* Most commonly occurs in patients with rheumatoid

arthritis and ankylosing spondylitis from ligament laxity* Widening of predental space seen on lateral plain film

Jefferson

fracture =C1 burstfracture(axialcompressn)

No * 33% with associated C2 fracture

* Low incidence of neurologic injury because of wide C1spinal canal

* Usually involves fractures of both the anterior andposterior C1 arches, often with 3 or 4 fracturefragments

* Complication: transverse ligament rupture, especially ifC1 lateral masses are !7 mm wider than expected(MRI recommended)

* Complication: vertebral artery injury (CT angiographyrecommended)

C1posteriorarchfracture(extension)

Yes * An associated C2 fracture (occurs 50% of time) makesthe posterior arch fracture unstable

* On plain films, no displacement of lateral masses onthe odontoid view and no prevertebral soft tissueswelling, unlike Jefferson burst fracture

C2 densfracture(flexion)

+/- * Type I (stable): Avulsion of dens with intact transverseligament

* Type II (unstable): Fracture at base of dens; 10% havean associated rupture of the transverse ligament MRIprovides definitive diagnosis of ligament rupture

* Type III (stable or unstable): Fracture of dens

extending into vertebral bodyHangmansfracture =C2spondylolisthesis(extension)

No * Bilateral C2 pedicle fractures* At risk for disruption of the posterior longitudinal

ligament (PLL), C2 anterior subluxation, and C2-C3disk rupture.

* Low risk for spinal cord injury because of C2 anteriorsubluxation, which widens spinal canal

Extensionteardropfracture

(extension)

No * Small triangular avulsion of anteroinferior vertebralbody, at insertion point of anterior longitudinal ligament

* Occurs most frequently at C2 level, but can occur in

lower cervical spine* Complication: central cord syndrome due to

ligamentum flavum buckling during hyperextension* Requires CT differentiation from very unstable flexion

teardrop fracture