Check list

- Septal deviation or spurs.
- Lamina papyracea-look for dchisccncc over entire length.
- Extent of Sphenoid pneumatization.
- Presence of Onodi cells.
- Optic nerve and Internal carotid artery prominence.
- Dehiscence of bone over optic nerve or carotid artery.
- Number, position and course of intcrsinus septa of the sphenoid.

Surgical importance

In axial sections, posterosuperior end of maxillary sinus is often mistaken for Onodi cells. Sphenoethmoid cells (Onodi cells) area is the most common spot of injury to the optic nerve. To avoid injury to the optic nerve, stay medial and inferior after perforation of the basal lamella.