axis fracture

• incidence: 6% of cervical spine injuries
• associated with atlas fractures in 8%

• hyperflexion injury: odontoid fracture

  type I

  avulsion of tip of odontoid (5-8%)

  difficult to detect

  type II

  fracture through base of dens (54-67%)

  complication: nonunion

  type III

  subdental injury (30-33%)

  prognosis: good

  • DDx:
    • os odontoideum
    • ossiculum terminale
    • hypoplasia/aplasia of dens

• hyperextension injury: hangman's fracture

© 2002, C.E. Kahn, Jr.
2002-04-18