| Anatomical landmark/length | Definition |
| Maxillofrontal point (Mf) | The junction between the frontomaxillary suture and medial orbital rim |
| Ectoconchion point (Ec) | The junction between the lateral orbital rim and the horizontal line that divides the orbital foramen into two equal parts |
| Supraorbital point (Os) | The superior junction between the superior orbital rim and the perpendicular bisector line of line Mf-Ec |
| Infraorbital point (Oi) | The inferior junction between the inferior orbital rim and the perpendicular bisector line of line Mf-Ec |
| Optic foramen point (Of) | Optic foramen |
| Orbital breadth | Mf-Ec |
| Orbital height | Os-Oi |
| Medial wall length | Mf-Of |
| Lateral wall length | Ec-Of |
| Orbital roof length | Os-Of |
| Orbital floor length | Oi-Of |
| Intraorbital distance (IOD) | Mf-Mf |
| Extraorbital distance (EOD) | Ec-Ec |