title: Measurement of occipitocervical angle.
abstract: METHODS
  This study compared the reliability of 3 techniques used to measure alignment between the occiput and cervical spine.
  
  
  OBJECTIVE
  Intraobserver and interobserver intraclass correlation coefficient were computed to determine the most reliable method to measure occipitocervical angle.
  
  
  BACKGROUND
  No studies have been performed comparing occipitocervical angle measurement techniques.
  
  
  METHODS
  The angles between the inferior endplate of second cervical vertebrae and the occiput line using the Chamberlain line, McRae line, and McGregor line were measured from lateral cervical radiographs of 30 healthy volunteers. Five spine surgeons made measurements.
  
  
  RESULTS
  Mean intraobserver variances of the angles using Chamberlain line, McRae line, and McGregor line were 2.0 degrees (ranging from 0 degrees-15 degrees), 4.7 degrees (from 0 degrees-28 degrees), and 1.5 degrees (from 0 degrees-9 degrees), respectively; intraobserver intraclass correlation coefficients of the angles were 0.956, 0.835, and 0.975. Mean interobserver variances of the angles using Chamberlain line, McRae line, and McGregor line were 2.3 degrees (from 0.4 degrees-6.4 degrees), 5.0 degrees (from 1.8 degrees-11.9 degrees), and 1.4 degrees (from 0 degrees-4.5 degrees), respectively; interobserver intraclass correlation coefficients were 0.939, 0.802, and 0.972. The highest reliability indexes were obtained for McGregor line.
  
  
  CONCLUSIONS
  The McGregor line is the most reproducible and reliable method for measurement of the occipitocervical angle.
authors.affiliation: Departments of Orthopaedic Surgery, The University of Tokyo, Tokyo, Japan. tkyort-office@umin.ac.jp
authors.forename: Naoki
authors.initials: N
authors.lastname: Shoda
authors.forename: Katsushi
authors.initials: K
authors.lastname: Takeshita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Seichi
authors.forename: Toru
authors.initials: T
authors.lastname: Akune
authors.forename: Susumu
authors.initials: S
authors.lastname: Nakajima
authors.forename: Yorito
authors.initials: Y
authors.lastname: Anamizu
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Miyashita
authors.forename: Kozo
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000886:Anthropometry / Q000379:methods*; D001368:Axis, Cervical Vertebra / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000379:methods*; D006801:Humans; D009333:Neck / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D015588:Observer Variation; D009777:Occipital Bone / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D021362:Palate, Hard / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D011859:Radiography; D012016:Reference Values; D015203:Reproducibility of Results