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Upper cervical spine fractures (C0 to C2)
In the upper neck stability depends on ligaments: a Jefferson fracture is stable while the transverse ligament is intact, a type 2 odontoid fracture tends to non-union and is usually fixed surgically, a hangman's fracture usually heals with external immobilisation, and craniocervical dissociation needs surgical fixation.
Why it matters in the exam
A Jefferson fracture is a burst fracture of the C1 ring from axial loading. The question: is the transverse ligament intact? On the open-mouth view, combined overhang of the C1 lateral masses beyond C2 of more than 7 mm (the "rule of Spence") suggests a ligament tear; today this is confirmed on MRI. Intact ligament — rigid collar or halo; torn ligament — C1-C2 fixation. An atlanto-dental interval (ADI) over 3 mm in an adult indicates instability. Odontoid fractures by Anderson-D'Alonzo: type 1 — tip of the dens, stable; type 2 — at the base of the dens, the commonest, with a high risk of non-union when displacement is 5 mm or more, age is over 50 or displacement is posterior; type 3 — extends into the vertebral body and usually heals with external immobilisation.
A hangman's fracture (traumatic spondylolisthesis of C2) is a bilateral fracture of the C2 pars interarticularis, usually from hyperextension with axial loading in a road crash. By Levine-Edwards: type 1 — displacement under 3 mm, collar; type 2 — displacement and angulation, halo or collar; type 2a — marked angulation with little displacement from a flexion-distraction mechanism, and traction must not be applied; type 3 — with facet dislocation, surgery. Atlanto-occipital dissociation is a severe, often fatal injury diagnosed by a widened condyle-C1 interval or the Harris rule of 12; treatment — occipitocervical fixation and no traction. In an elderly patient with a type 2 odontoid fracture the choice between a collar and surgical fixation is balanced against overall risk.
Key points
- Jefferson — axial loading; stability depends on the transverse ligament.
- Rule of Spence: over 7 mm — ligament tear.
- Odontoid type 2 — commonest, risk of non-union.
- Hangman's — C2 pars, most patients treated with external immobilisation.
- Atlanto-occipital dissociation — no traction, occipitocervical fixation.
Summary table
| Injury | Mechanism | Sign of instability | Treatment |
|---|---|---|---|
| Jefferson (C1) | Axial loading | Lateral mass overhang over 7 mm — transverse ligament tear | Intact ligament — collar or halo; torn — C1-C2 fixation |
| Type 2 odontoid fracture | Flexion or extension | Displacement 5 mm or more, age over 50 | Anterior screw or posterior C1-C2 fixation |
| Type 3 odontoid fracture | Flexion | Extends into the C2 body | External immobilisation |
| Hangman's (C2) | Hyperextension and axial loading | Levine-Edwards; 2a — no traction | Most — collar or halo; 3 — surgery |
| Atlanto-occipital dissociation | Violent distraction | Harris rule of 12 | Occipitocervical fixation; no traction |
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Sources
- AANS/CNS Guidelines for the Management of Acute Cervical Spine and Spinal Cord Injuries, 2013 — Occipital condyle fractures, atlas fractures, odontoid fractures, hangman's fractures
- American College of Surgeons ATLS, 10th edition (2018) — Spine and spinal cord trauma
- AO Spine Upper Cervical Injury Classification, 2021 — Classification principles
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.