title: Harris or axis ring: an aid in diagnosing low (type 3) odontoid fractures.
abstract: OBJECTIVE
  To present our experience of diagnosing fractures of the odontoid process on lateral radiographs of the cervical spine that show the Harris (axis) ring.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Teaching hospital, Belgium.
  
  
  METHODS
  12 patients with multiple injuries, including cervical spine, 8 of them unconscious or uncooperative.
  
  
  METHODS
  Cross table lateral view of the cervical spine.
  
  
  METHODS
  Identification of otherwise hidden type 3 axial fractures.
  
  
  RESULTS
  Diagnosis of low odontoid fractures in all cases.
  
  
  CONCLUSIONS
  The Harris ring is disrupted in low odontoid fractures and intact in fractures of the odontoid process. Awareness of this sign will allow diagnosis of otherwise hidden axial fractures.
authors.affiliation: Department of Emergency Medicine, University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: L J
authors.initials: LJ
authors.lastname: Mortelmans
authors.forename: E A
authors.initials: EA
authors.lastname: Geusens
authors.forename: M B
authors.initials: MB
authors.lastname: Sabbe
authors.forename: H H
authors.initials: HH
authors.lastname: Delooz
mesh_terms: D000293:Adolescent; D000328:Adult; D001368:Axis, Cervical Vertebra / Q000000981:diagnostic imaging* / Q000293:injuries; D006801:Humans; D008297:Male; D009809:Odontoid Process / Q000000981:diagnostic imaging* / Q000293:injuries*; D011859:Radiography; D012189:Retrospective Studies; D016103:Spinal Fractures / Q000000981:diagnostic imaging*