Unilateral facet dislocation

Last revised by Sandeep Singh Awal on 5 Jan 2022

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

MRI is used to detect other soft tissue injuries like disc herniation and cord edema/contusion.

30% of these injuries are associated with neurological deficit.

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Figure 1: unilateral facet dislocation
    Drag here to reorder.
  • Case 1: unilateral facet lock
    Drag here to reorder.
  • Case 2
    Drag here to reorder.
  • Case 3
    Drag here to reorder.
  • Case 4: locked facet on left
    Drag here to reorder.