Table 2.

Planes definitions

Landmark	Definition	Type
Horizontal maxillary plane	Anterior nasal spine, right posterior choanae, left posterior choanae	Plane defined by 3 points
Orbital floor	Lacrimal canal, superior orbital fissure (posterior–inferior end), medial inferior orbital fissure	Plane defined by 3 points
Lateral orbital wall	Superior orbital fissure (anterior–superior end), superior orbital fissure (posterior–inferior end), medial inferior orbital fissure	Plane defined by 3 points
Orbital roof	Foramen caecum, planum sphenoidale, small wing of the sphenoid	Plane defined by 3 points
Medial orbital wall	Superior orbital fissure (anterior–superior end), anterior clinoid process, fronto–maxillary suture	Plane defined by 3 points
Anterior orbital wall	Fronto–maxillary suture, fronto–zygomatic suture, perpendicular to the horizontal maxillary plane	Plane defined by 2 points and perpendicular to another plane