Odontoid fracture

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  • Also known as dens fracture
  • Only stable if fracture confined to avulsion of the tip (superior to transverse ligament)[1]
  • Bimodal distribution
    • Young - blunt trauma to head, flexion/extension injury
    • Elderly - fall, with higher morbidity/mortality
  • False positives
    • Dens and vertebral body are connected by cartilage at young age, and do not fuse until 3-6 years of age (up to 11 years of age)
    • Os odontoideum - normal variant

Clinical Features

  • Frequently involves other cervical spine injuries
  • 25% associated with neurologic injury

Differential Diagnosis

Cervical Spine Fractures and Dislocations


  • Imaging
    • Xray: AP, lateral, open-mouth odontoid view of cervical spine
    • CT for further assessment if fracture identified


  • Type I: Oblique avulsion fracture of tip of odontoid; alar ligament avulsion
    • Stable
    • Atlanto-occipital instability (AAI) should be ruled out with flexion and extension films
    • AAI requires surgical management
  • Type II: Fracture at base of odontoid process where it attaches to C2; Fracture through waist
    • Unstable
    • high nonunion rate due to interruption of blood supply
      • Young: Halo if no risk factors for nonunion, Surgery if risk factors for nonunion
      • Elderly: Collar if not surgical candidates, Surgery if surgical candidates
  • Type III: Extension of the fracture through upper portion of body of C2
    • Unstable



See Also


  1. Clark, J., Abdullah, K. and Mroz, T. (2011) Biomechanics of the Craniovertebral Junction. Edited by Vaclav Klika