title: Effects of head and body positions on 2- and 3-dimensional configuration of the oropharynx with jaw protruded: a magnetic resonance imaging study.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effect of altering changing head and body positions on the 2- and 3-dimensional (3D) configuration of the oropharynx with jaw protrusion.
  
  
  METHODS
  Twelve healthy individuals (8 male, 4 female) with no history of sleep disturbances were invited to participate. For each subject, an acrylic splint was made with the mandible in protruded position. Subjects were imaged using magnetic resonance imaging in 4 different jaw, head, and body positions: 1) supine without protrusion; 2) supine with jaw protrusion; 3) supine with head rotation and jaw protrusion; and 4) laterally recumbent position with jaw protrusion. The 2- and 3D images of the upper airway in different positions were reconstructed by using a free DICOM reconstruction software. The dimension changes (anteroposterior and lateral dimensions, cross-sectional area, and volume) of the oropharynx (divided into retropalatal region and retroglossal region) were calculated and analyzed. Statistical analyses were performed using the Bartlett test and 1-way analysis of variance with α = .05.
  
  
  RESULTS
  Compared with nonprotruded position, dimensions of the oropharynx for both retropalatal region and retroglossal regions were found to be greater than with jaw protrusion. Head and body positions had little effect on configuration of the oropharynx with jaw protrusion in either 2- or 3D. The only change noted was a greater anteroposterior dimension of retropalatal region with head rotation and lateral supine position compared with the supine position.
  
  
  CONCLUSIONS
  Head and body positions have little effect on 2- and 3D airway dimensions on supine patients with jaw protrusion.
authors.affiliation: Research Institute of Stomatology, Department of Oral Special Consultation, Nanjing Medical University, Nanjing, China. zhangwei0508@hotmail.com
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Xiaomeng
authors.initials: X
authors.lastname: Song
authors.forename: Shin Ichi
authors.initials: SI
authors.lastname: Masumi
authors.forename: Tatsurou
authors.initials: T
authors.lastname: Tanaka
authors.forename: Qingping
authors.initials: Q
authors.lastname: Zhu
mesh_terms: D002508:Cephalometry / Q000379:methods; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging; D009960:Oropharynx / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D011187:Posture; D011859:Radiography; D012016:Reference Values