Odontoid fracture


The three types of odontoid fracture. Type II and type III are unstable fractures.
  • Fracture of C2 (dens)
  • Bimodal age distribution
    • Young - injury secondary to blunt trauma to head or flexion/extension injury
    • Elderly - injury secondary to fall, higher morbidity/mortality than young patients
      • Increased risk of fracture due to bone loss, which is disproportionate at C2 relative to rest of skeleton
  • Frequently associated with other cervical spine injuries
  • 25% associated with neurologic injury/deficit
  • Os odontoideum (normal variant) can look like a Type II odontoid fracture on imaging, causing false postive


  • Type I: Oblique avulsion fracture of tip of odontoid; alar ligament avulsion
    • Stable fracture
  • Type II: Fracture at base of odontoid where it meets C2 body
    • Unstable fracture
    • High risk of nonunion (30%) due to interruption of blood supply
  • Type III: Extension of the fracture through upper portion of body of C2
    • Unstable fracture

Vertebral fractures and dislocations types

Vertebral anatomy.
Numbering order of vertebrae.

Clinical Features

  • Neck pain
  • May have neurologic deficit

Differential Diagnosis

Neck Trauma


  • CT is the imaging study of choice
  • Cervical spine x-ray may be performed if CT unavailable
    • Must include open-mouth odontoid view


  • Cervical spine motion restriction via hard cervical collar
  • Consult spine surgery


  • Admit
  • May consider discharge with hard cervical collar for Type I fracture (stable)
    • Consider only in consultation with spine surgery service[1]

See Also


  1. Waterbrook, A. (2016). Sports medicine for the emergency physician: a practical handbook. Cambridge: Cambridge University Press.