Table 1 Reference points and planes
Landmarks (abbreviation) | Description |
|---|---|
Points | |
Orbitale (Or) | The lowest point on the lower margin of the bony orbit (OrR, right side; OrL, left side) |
Porion (Po) | The highest point of the skeletal external auditory meatus (PoR, right side; PoL, left side) |
Basion (Ba) | Midpoint of the anterior margin of the foramen magnum on the occipital bone |
Crista galli (Cg) | The most superior point of crista galli located in the ethmoid bone |
Mesiobuccal cusp (MBC) | Mesiobuccal cusp of maxillary first molar (MBCR: right; MBCL; left) |
Mandibular foramen (ManF) | The center point of the opening of the inferior alveolar nerve canal |
Mental foramen (MF) | The center of mental foramen (MFR, right side; MFL, left side) |
Lower incisor (L1) | The midpoint of the incisal edge of the mandibular central incisors |
IANant | The most anterior point of the anterior loop of the inferior alveolar nerve |
IANinf | The most inferior point of the anterior loop of the inferior alveolar nerve |
Planes | |
Mid-axial plane (MAP) | A plane passing through OrR, OrL and PoL |
Mid-sagittal plane (MSP) | A plane passing through Cg, Ba and normal to MAP |
Coronal plane (COP) | A plane passing through Ba, and normal to MAP and MSP |
Occlusal plane (OP) | A plane passing through the bilateral mesiobuccal cusp of maxillary first molar and the L1 |
Mandibular sagittal plane (MnSP) | A plane passing through ManF, MF and normal to OP |
Horizontal reference plane (HRP) | A plane passing through MF and parallel to OP |
Vertical reference plane (VRP) | A plane passing through MF and normal to OP and MnSP |