Anterior Clinoid Pneumatisation
Imageset Description
Aeration of the anterior clinoid process (as seen in this image) may originate from Onodi cells.
An Onodi cell is defined as the posteriormost ethmoid cell that features an endoscopically identifiable bulge in the optic canal, even if it is minimal. Patients who have an Onodi cell are also at increased risk for optic nerve injury during endoscopic sinus surgery. The incidence of Onodi cells is 8-14%.
On this image, also note the pneumatised dorsum sella
