During an endoscopic transsphenoidal approach, the sphenoid sinus ostium is identified. Where is it located?
- A Lateral to the superior turbinate, at the level of the middle meatus
- B Medial to the superior turbinate, in the sphenoethmoidal recess, approximately 1.5 cm above the choana ✓
- C Inferior to the middle turbinate axilla, adjacent to the maxillary line
- D Posterior to the basal lamella of the middle turbinate at the level of the horizontal fovea ethmoidalis
Correct answer: B. Medial to the superior turbinate, in the sphenoethmoidal recess, approximately 1.5 cm above the choana
Explanation
The natural sphenoid ostium lies in the sphenoethmoidal recess, medial to the superior or supreme turbinate, roughly 1.5 cm above the choanal margin and about 7 cm from the nasal spine along the sphenoid face. Placing it medially protects the internal carotid artery and optic nerve, which lie laterally in the sphenoid wall. Options describing the middle meatus and frontal recess relate to maxillary and frontal surgery respectively.
Reference: Gray's Anatomy, 42nd ed.
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Written and medically reviewed by the StethoPrep medical team.