A surgeon performs a transnasal sphenoidotomy for isolated sphenoid sinusitis. To enter the sphenoid sinus safely without injuring the internal carotid artery laterally or creating a cerebrospinal fluid leak superiorly, the ostium should be identified and enlarged medially. Which landmark guides identification of the sphenoid ostium?

• A Inferior turbinate tail, at the level of the choana
• B Superior turbinate, medial to which the ostium lies about 1 cm above the choana ✓
• C Middle turbinate axilla, at the level of the frontal recess
• D Posterior attachment of the uncinate process

Explanation

The sphenoid ostium lies medial to the superior turbinate, approximately 1 to 1.5 cm above the choana, and enlarging it inferomedially avoids the carotid canal laterally and the planum and sella superiorly. The transsphenoidal approach between the septum and superior turbinate exploits this. The middle turbinate axilla and uncinate relate to frontal and maxillary drainage respectively.

Reference: Cummings Otolaryngology: Head and Neck Surgery, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.