In functional endoscopic sinus surgery (FESS) for chronic rhinosinusitis, the key anatomical landmark that guides the surgery and whose recognition prevents orbital complications is:

• A Middle turbinate attachment to the lamina papyracea
• B Basal lamella (ground lamella) of the middle turbinate
• C Uncinate process attachment to the lamina papyracea
• D Anterior ethmoidal artery in the roof of the ethmoid ✓

Explanation

The anterior ethmoidal artery traverses the ethmoid roof in a bony mesentery (Keros type) and is at risk during ethmoid dissection — injury causes retrobulbar haematoma. The Keros classification describes the depth of the olfactory fossa: Type I (1-3mm), Type II (4-7mm), Type III (8-16mm) — Type III has the highest risk of intracranial penetration. The basal lamella separates anterior from posterior ethmoid cells, while the uncinate guides the maxillary ostium.

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.