1. Atlanto-Occipital Dislocations – Children, Lateral Neck XR, Power’s Ratio > 1, craniocervical fusion
  2. Atlanto-Axial Dislocation – Rheum, Down Syndrome, Lateral Neck XR, ADI > 3.5 unstable
  3. Atlanto-Axial Subluxation – Grisel’s Syndrome, dynamic CT
  4. Unilateral Facet Dislocation – reverse hamburger sign; closed reduction
  5. Bilateral Facet Dislocation – reverse hamburger sign; surgery
Risk Factors/Mechanism
Atlanto-Occipital Dislocation

High energy trauma results in a tear of the tectorial membrane and alar ligament at the craniocervical junction

Lateral Neck X-ray
Powers Ratio
= greater than 1
basion to C1 arch
opisthion to C1 arch

Cranio‐cervical fusion with internal fixation

Atlanto-Axial Dislocation

Damage to transverse ligament allows C1 (atlas) to move forward resulting in an increased atlanto dens interval (ADI)

More common in Down Syndrome, Rheumatoid Arthritis

Atlanto-Dens Interval
> 3.5mm considered unstable
> 10mm indicates surgery in RA

posterior occipitocervical/C1–C2 fusion after transoral odontoidectomy or periodontoid tissue release

Atlanto-Axial Rotary Subluxation

Grisel Syndrome – inflammatory or infectious process of the atlanta-axial joint results in atlanto-axial subluxation

dynamic CT is the gold standard

  • Soft collar, therapy, NSAIDS and stretching exercise program
  • home head halter traction therapy (5lbs)
Unilateral Facet Dislocation
  • most frequently missed cervical spine injury x-ray
  • leads to ~25% subluxation on xray
  • associated with monoradiculopathy that improves with traction

CT Spine that shows reverse hamburger sign

Cervical orthosis or external immobilization (6-12 weeks)

Bilateral Facet Dislocation 
  • leads to ~50% subluxation on xray
  • often associated with significant spinal cord injury

CT Spine that shows reverse hamburger sign

Emergent closed reduction if neuro deficits, if not then get MRI