Sleep and Breathing

, Volume 14, Issue 4, pp 353–358 | Cite as

Soft palate length and upper airway relationship in OSA and non-OSA subjects

  • Yuko Shigeta
  • Takumi Ogawa
  • Ikawa Tomoko
  • Glenn T. Clark
  • Reyes Enciso
Original Article



The narrowest area of the airway between the posterior nasal opening and the epiglottis is usually located in the retro palatal area. Many consider this the most likely site of airway obstruction during an obstructive sleep apnea (OSA) event. The aim of this study was to investigate the differences in soft palate and airway length between OSA and non-OSA patients.


In this study, we analyzed the ratio of the soft palate and the upper airway length in 45 consecutive patients. Twenty-five had an Apnea–Hypoapnea Index of more than five events per hour and were classified in the OSA group (male, 19; female, 6). These patients were compared with 20 normal controls (male, 12; female, 8). Controls who complained of snoring did have sleep studies (n = 5). The other fifteen controls were clinically asymptomatic and did not have sleep studies. Medical computed tomography scans were taken to determine the length of the upper airway and the soft palate length measured in the midsagittal image.


Soft palate length was significantly larger in OSA patients compared to controls (p = 0.009), and in men compared to women (p = 0.002). However, there were no differences in airway length. The soft palate length, as a percent of oropharyngeal airway length, was significantly larger in OSA patients compared to controls (p = <0.0001) and in men compared to women (p = 0.02). Soft palate length increases significantly with age by 0.3 mm per year in males (after adjustment for body mass index (BMI) and OSA). Soft palate length as a percent of airway length is larger in OSA patients and increases significantly with BMI in males only after adjusting for age.


In this study, OSA patients had a longer soft palate in proportion to their oropharyngeal airway compared to controls as well as men compared to women. This proportion could be used for identifying patients at risk for OSA in combination with age.


Soft palate length Oropharyngeal airway Obstructive sleep apnea Computerized tomography 



Dr. Enciso was partially supported by the National Institute of Dental Craniofacial Research grant number 5 K25 DE016391. Dr. Ogawa was partially supported by “High-Tech Research Center” Project for Private Universities and grant number 18390501: matching fund subsidy from the Ministry of Education, Culture, Sports, Science and Technology, Japan. The authors have no conflict of interests.


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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Yuko Shigeta
    • 1
    • 2
  • Takumi Ogawa
    • 2
  • Ikawa Tomoko
    • 2
  • Glenn T. Clark
    • 1
  • Reyes Enciso
    • 3
  1. 1.Orofacial Pain/Oral Medicine Center, Division of Diagnostic Sciences, School of DentistryUniversity of Southern CaliforniaLos AngelesUSA
  2. 2.Department of Fixed Prosthodontic DentistrySchool of Dental Medicine, Tsurumi UniversityYokohamaJapan
  3. 3.Division of Craniofacial Sciences and Therapeutics, School of DentistryUniversity of Southern CaliforniaLos AngelesUSA

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