Unilateral facet dislocation is a relatively stable type of facet dislocation.
Flexion/distraction associated with rotation. The inferior articular facet of vertebral above moves over the superior facet of the vertebral below and becomes locked. It usually affects C4-C5 or C5-C6 levels.
anterolisthesis of less than 25 - 50%
- as the other normally aligned facet prevents displacement greater than this
- if there is a greater amount of displacement, then bilateral facet joint dislocation should be considered
- bow-tie sign: rotated facets on lateral view
- rotation and misalignment of spinous processes on AP view which point to the involved side
- widening of the interspinous space at affected level
- naked facet or inverted hamburger sign may be present
- also helpful to detect other fractures and their extent
MRI is used to detect other soft tissue injuries like disc herniation and cord edema/contusion.
Treatment and prognosis
30% of these injuries are associated with neurological deficit.
- 1. Nuñez DB, Zuluaga A, Fuentes-Bernardo DA et-al. Cervical spine trauma: how much more do we learn by routinely using helical CT?. Radiographics. 1996;16 (6): 1307-18. Radiographics (abstract) - Pubmed citation
- 2. Shapiro SA. Management of unilateral locked facet of the cervical spine. Neurosurgery. 1994;33 (5): 832-7. Pubmed citation
Related Radiopaedia articles
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