title: The ethmo-frontal angle: a new anatomic and radiologic landmark for use in sinus surgery.
abstract: OBJECTIVE
  To identify anatomic and radiologic landmarks to assist with frontal sinus surgery.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  Sinus CT scans of 50 patients were evaluated with respect to a new radiologic and anatomic landmark, the ethmo-frontal angle (EFA).
  
  
  RESULTS
  Right-sided EFA ranged from 135 to 171 degrees. Left-sided EFA ranged from 136 to 167 degrees. Measurements of both sides displayed a normal distribution. When right and left sides within individuals were compared, there was no correlation to indicate a high degree of variation between any particular patient's right and left side EFA.
  
  
  CONCLUSIONS
  The EFA is a new landmark to assist otolaryngologists during surgery on and around the frontal sinus. Normal values for this angle have been presented. Surgeons should be aware that asymmetry in a patient's EFA is common, and each side should be examined individually.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA. sam.s.becker@gmail.com
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Becker
authors.forename: Peter A
authors.initials: PA
authors.lastname: Beddow
authors.forename: James A
authors.initials: JA
authors.lastname: Duncavage
mesh_terms: D005004:Ethmoid Bone / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000601:surgery; D005626:Frontal Sinus / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D013517:Otorhinolaryngologic Surgical Procedures; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed