Table 3 Cephalometric landmarks and measurements of the craniofacial structures

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