Head and Neck Imaging

Optic canal, bony dehiscence

the optic canal can project into the lumen of the sphenoid sinus or Onodi cells, and a bony dehiscence of its wall may be present. Sometimes the optic nerve passes through the sphenoid sinus or sphenoethmoid cell as a tissue column, surrounded by pneumatized space. Recognition of this variant is important, to avoid inadvertent damage to the optic nerve during functional endoscopic sinus surgery.

RH