From: Cephalometric norms for the upper airway of 12-year-old Chinese children
Variables | Definition |
---|---|
Landmarks | |
Po | Porion, the mid point of the line connecting the most superior point of the external auditory canal on both sides |
Or | Orbitale, the lowest point on the average of the left and right inferior borders of the bony orbit |
ANS | Anterior nasal spine, the tip of the median, sharp bony process of the maxilla |
PM | Pterygo-maxillare, the point at the junction fo the pterygo-maxilla and the posterior nasal spine |
U | Uvula, the tip of the uvula |
UPW | Upper pharyngeal wall, point of intersection of the line NL to the posterior pharyngeal wall |
MPW | Middle pharyngeal wall, intersection of the perpendicular line from U to the posterior pharyngeal wall |
LPW | Lower pharyngeal wall, intersection of the perpendicular line from V to the posterior pharyngeal wall |
V | Vallecula, the intersection of the epiglottis and the base of the tongue |
AH | Anterior hyoid, the most anterior and superior point on the body of the hyoid bone |
C2 | 2nd cervical vertebrae, the point at the most anterior-inferior position on the second cervical vertebrae |
C3 | 3rd cervical vertebrae, the point at the most anterior-inferior position on the third cervical vertebrae |
FH | Frankort horizontal plane, line joining the Or to the Po |
NL | Nasal line, line joining the ANS and Pm |
CV | Cervical vertebrae, the line joining the C2 and C3 |
Measurements | |
PM-U (mm) | Length of soft palate, distance from PM to U |
SPT (mm) | Soft palate thickness, represents the maximal thickness of the soft palate measured perpendicular to PM-U line |
NL/PM-U (°) | Inclincation of the long axis of the soft palate relative to the nasal line |
PM-UPW (mm) | Depth of the nasopharyngeal airway space from PM to UPW |
U-MPW (mm) | Depth of the oropharyngeal airway space from U to MPW |
PASmin (mm) | The shortest distance between the base of the tongue and the posterior pharyngeal wall, the narrowest sagittal airway space |
V-LPW (mm) | Depth of the hypopharyngeal airway space from V to LPW |
AH-FH (mm) | Position of the hyoid bone in vertical plane, from AH perpendicular to FH |
AH-CV (mm) | Position of the hyoid bone in horizontal plane, from AH to CV and parallel to FH |