Table 1 The reference point, line, and the plane
Landmarks | Abbreviation | Description |
|---|---|---|
Point | ||
Nasion | Na | The middle point of the junction of the frontal and the two nasal bones |
Porion | Po | The highest point of the skeletal external auditory meatus (PoR, right side; PoL, left side; PoC, center of the PoR and PoL, automatically determined) |
Orbitale | Or | The lowest point in the lower margin of the bony orbit (OrR, right side; OrL, left side; OrC, center of the OrR and OrL, automatically determined) |
Pogonion | Pog | The most anterior point of the mandible in the midline |
Mental foramen | MF | The center of mental foramen (MFR, right side; MFL, left side) |
Gonion | Go | The most inferior, posterior, and lateral point of the angle of the mandible (GoR, right side; GoL, left side) |
Sigmoid notch | SN | The deepest point between the condylar and coronoid process of the mandible (SNR, right side; SNL, left side) |
Line | ||
FH line | A line projecting the PoC and OrC | |
Plane | ||
McNamara plane | pMcN | A plane through the nasion and perpendicular to the FH line |
Occlusal plane | pOcc | A plane through the bilateral mandibular first molar mesiobuccal cusp and the middle of the lower incisal edge |
MF_H plane | pMF_H | A plane through the MF point and parallel to the pOcc |
MF_V plane | pMF_V | A plane through the bilateral MF and perpendicular to the pOcc |