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Variable | Unit | Definition |
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Landmarks | | |
ANS | | Anterior nasal spine, the tip of the median, sharp bony process of the maxilla |
PM | | Pterygo-maxillare, the point at the junction of the pterygo-maxillary fissure and the posterior nasal spine |
U | | Uvula, the tip of the uvula |
UPW | | Upper pharyngeal wall, the point of intersection of the line NL to the posterior pharyngeal wall |
MPW | | Middle pharyngeal wall, the point of intersection of the perpendicular line from U to the posterior pharyngeal wall |
LPW | | Lower pharyngeal wall, the point of intersection of the perpendicular line from V to the posterior pharyngeal wall |
V | | Vallecula, the point of intersection of the epiglottis and the base of the tongue |
NL | | Nasal line, the line joining ANS and PM |
S | | Center of the sella turcica |
N | | Nasion, the deepest point in the concavity of nasofrontal suture |
A | | A point, the deepest point in the concavity of the anterior maxilla between the anterior nasal spine and the alveolar crest |
B | | B point, the deepest point in the concavity of the anterior mandible between the alveolar crest and the pogonion |
Me | | Menton, the most inferior point on the body of the chin |
Go’ | | Gonion’ point, the point of intersection of the tangents of the inferior and posterior borders of the mandible |
Measurements | | |
PM-UPW | mm | Depth of the nasopharyngeal airway space from PM to UPW |
U-MPW | mm | Depth of the retropalatal oropharyngeal airway space from U to MPW |
PASmin | mm | Depth of the retroglossal oropharyngel airway space, the shortest distance between the base of the tongue and the posterior pharyngeal wall |
V-LPW | mm | Depth of the hypopharyngeal airway space from V to LPW |
PM-U | mm | Length of soft palate, the distance from PM to U |
SPT | mm | Soft palate thickness, the maximal thickness of the soft palate measured perpendicular to PM-U line |
NL/PM-U | ° | Inclination of the long axis of the soft palate relative to the nasal line |
SNA | ° | Angle between the S-N line and the N-A line |
SNB | ° | Angle between the S-N line and the N-B line |
ANB | ° | Angle between the N-A line and the N-B line |
TAFH | mm | Total anterior facial height, the distance from N to Me |
LAFH | mm | Lower anterior facial height, the distance from the intersection of N-Me line and NL line to Me |
TPFH | mm | Total posterior facial height, the distance from S to Go’ |
MP/SN | ° | Angle between the S-N line and Me-Go’ line |
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