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Table 3 Cephalometric landmarks and measurements of the craniofacial structures

From: Cephalometric norms for the upper airway of 12-year-old Chinese children

Variables Definition
Landmarks  
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
Ui Upper incisor tip
Li Lower incisor tip
B B point, the deepest point in the concavity of the anterior mandible between the alveolar crest and the pogonion
Gn Gnathion, the most anteroinferior point on the bony chin
Me Mention, the most inferior point on the body chin
Go’ Gonion’ point, the intersection of the tangents of inferior and posterior borders of the mandible
Ar The intersection of the posterior border of the ramus with inferior surface of the cranial base
Cd Condylion, the most posterosuperior point of the condylar head
c2sp The most superior posterior point of the second cervical vertebra
c2ip The most inferior posterior point of the second cervical vertebra
c4ip The most inferior posterior point of the fourth cervical vertebra
MxPl Maxillary plance, equal to NL (ANS-PM)
MnPl Mandibular plane, line joining Me and Go
OPT Odontoid process tangent, line joining c2sp and c2ip
Measurements  
SNA (°) The angle between the S-N line and the N-A line
SNB (°) The angle between the S-N line and the N-B line
ANB (°) The angle between the N-A line and the N-B line
MnPl/SN (°) Mandibular plane angle, the angle between the MnPl and the S-N line
MxPl/MnPl (°) Maxillomandibular plane angle, the angle between the MxPl and the MnPl
MxMn-DF (mm) Masiilomandibular difference, the length of Cd-Gn minus the length of Co-A
TAFH (mm) The distance from N to Me
TPFH (mm) The distance from S to Go
Y axis/FH (°) The angle between S-Gn line and FH plane
Overjet (mm) The distance between Ui and Li, parallel to the FH plane
Overbite (mm) The distance between Ui and Li, perpendicular to the FH plane
OPT-SN (°) The angle between the OPT and the S-N line
c2sp-c4ip-SN (°) The angle between the c2sp-c4ip line and the S-N line
Body length (mm) The distance between Go’-Me