Table 1 Definition of the landmarks, planes and airway measurements used in the research
| Â | Definition |
|---|---|
A point | Deepest anterior point in concavity of anterior maxilla |
B point | Deepest anterior point in concavity of anterior mandible |
Gn point | The most anterior and inferior point of the chin |
N point | Most anterior point of frontonasal suture in midsagittal plane |
Airway height | The distance from roof of the airway to the upper border of larynx |
Total airway volume | Airway extending from roof of the airway to the upper border of larynx |
CSA | Cross-sectional area of pharyngeal airway section |
APL | Antero-posterior length of pharyngeal airway section |
LTW | Largest transverse width of pharyngeal airway section |
Hard palate plane | Plane parallel to FH plane and passing through most posterior point of hard palate |
Soft palate plane | Plane parallel to FH plane and passing through the middle point of soft palate and PNS |
Tongue plane | Plane parallel to FH plane and passing through the middle point of soft palate and epiglottis point. |
Epiglottis plane | Plane parallel to FH plane and passing through Most posterior point of epiglottis |
Soft palate length | The distance from PNS to the top of soft palate |
Soft palate angle | The angel formed by soft palate and hard palate |
Horizontal tongue length | The horizontal distance from the last point of the tongue to the internal border of the mandible |
Vertical tongue length | The distance from the top of the tongue to the epiglottis plane |