title: Cephalometric norms for the upper airway of 12-year-old Chinese children.
abstract: OBJECTIVE
  To establish cephalometric norms for the upper airway of 12-year-old Chinese children, and to assess these norms with regard to gender, age, ethnicity and other craniofacial structures.
  
  
  METHODS
  Lateral cephalograms were obtained from a random sample of 425 12-year-old Chinese children (224 boys and 201 girls) to establish the Chinese norms, and from a matched group of 108 12-year-old Caucasian children (61 boys and 47 girls) as an ethnic comparison. Published data on the upper airway norms of Chinese adults were used to make age comparisons. Nine upper airway and 14 craniofacial variables were measured.
  
  
  RESULTS
  Chinese boys tended to have a thicker soft palate (P = 0.008), and less depth in the retropalatal (P = 0.011), retroglossal (P = 0.034) and hypopharyngeal (P < 0.001) pharynx than Chinese girls, whereas no gender dimorphism was found in Caucasian children. Ethnic differences were found in the depth of the retroglossal oropharynx in both genders and the position of the hyoid bone in boys. Compared with Chinese adults, the overall size of the upper airway in Chinese children was smaller. The mandibular body length and the craniocervical inclination were found to be statistically significantly, albeit weakly correlated with upper airway variables.
  
  
  CONCLUSIONS
  Cephalometric norms for the upper airway of Chinese 12-year-old children were established, indicating gender-specific differences, and some ethnic differences were found in comparison with those of 12-year-old Caucasian children. An association between the mandibular body length and the craniocervical inclination with upper airway variables was also noticeable.
authors.forename: Min
authors.initials: M
authors.lastname: Gu
authors.forename: Colman P J
authors.initials: CP
authors.lastname: McGrath
authors.forename: Ricky W K
authors.initials: RW
authors.lastname: Wong
authors.forename: Urban
authors.initials: U
authors.lastname: Hägg
authors.affiliation: Orthodontics, Faculty of Dentistry, the University of Hong Kong, 34 Hospital Road, Hong Kong, SAR, China. yangyanq@hku.hk.
authors.forename: Yanqi
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000367:Age Factors; D002508:Cephalometry / Q000379:methods*; D002648:Child; D002681:China; D005260:Female; D006801:Humans; D007830:Larynx / Q000033:anatomy & histology*; D008297:Male; D049451:Nomograms; D010614:Pharynx / Q000033:anatomy & histology*; D015203:Reproducibility of Results; D012737:Sex Factors