During functional endoscopic sinus surgery (FESS), the most critical landmark used to identify the ethmoid roof and prevent intracranial entry is:

• A Skull base attachment of the superior turbinate (cribriform plate)
• B The fovea ethmoidalis identified by orbital periosteum medially
• C Horizontal ground lamella of the middle turbinate ✓
• D The agger nasi cell anterior wall

Explanation

The horizontal (horizontal portion of the ground lamella) or basal lamella of the middle turbinate attaches superiorly to the skull base at the cribriform plate and serves as the critical landmark for the ethmoid roof during FESS. Straying superior and medial to this attachment risks cribriform plate violation and CSF leak. The fovea ethmoidalis is the ethmoid roof itself — identified by removing overlying ethmoid cells carefully. The agger nasi is an anterior reference point.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.