While performing a Draf IIb frontal sinusotomy, the surgeon must first identify the largest and most constant anterior ethmoid cell, which forms the posteromedial boundary of the frontal recess and must be opened to gain frontal sinus access. This cell is the:

• A Agger nasi cell ✓
• B Supraorbital ethmoid cell
• C Haller cell
• D Sphenoethmoid (Onodi) cell

Explanation

The agger nasi cell is the most anterior ethmoid air cell, present in nearly all patients, lying immediately inferior and anterior to the frontal recess. Its size directly determines the patency of the frontal recess, so its removal is the key step in endoscopic frontal sinusotomy. The supraorbital ethmoid cell lies posterosuperiorly and can mimic the frontal sinus on imaging, while the Onodi cell relates to the sphenoid and optic nerve.

Reference: Scott-Brown's Otorhinolaryngology Head and Neck Surgery, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.