A CT scan of the paranasal sinuses shows an air-filled ethmoid air cell extending along the floor of the orbit, adjacent to the roof of the maxillary sinus, narrowing the infundibulum. Which anatomical variant is this?
- A Agger nasi cell
- B Onodi cell
- C Haller cell ✓
- D Concha bullosa
Correct answer: C. Haller cell
Explanation
A Haller cell, or infraorbital ethmoid cell, pneumatizes into the orbital floor and sits above the maxillary sinus roof. When large it narrows the maxillary infundibulum and predisposes to recurrent maxillary sinusitis, and it must be recognised before uncinectomy to avoid orbital entry. The Onodi cell lies superolateral near the optic nerve, and the agger nasi cell is anterior in the frontal recess, so both are anatomically inconsistent with an infraorbital location.
Reference: Stammberger, Functional Endoscopic Sinus Surgery / Cummings Otolaryngology, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.