1 — Median palatine suture; 2 — Pterygoid process, lateral plate; 3 — Pterygoid process, medial plate; 4 — Choana; Posterior nasal aperture; 5 — Inferior orbital fissure; 6 — Pterygoid fossa; 7 — Opening of sphenoidal sinus; 8 — Anterior clinoid process; 9 — Septum of sphenoidal sinuses; 10 — Optic canal; 11 — Superior orbital fissure; 12 — Middle nasal concha; 13 — Ethmoid; Ethmoidal bone, perpendicular plate; 14 — Inferior nasal concha; 15 — Palatine bone, pyramidal process; 16 — Vomer; 17 — Maxilla, palatine process; 18 — Incisive foramina
