During an endoscopic transsphenoidal approach, the natural ostium of the sphenoid sinus is identified in relation to which structure?
- A Medial to the superior turbinate, approximately 1.5 cm above the choana ✓
- B Lateral to the middle turbinate axilla
- C Inferior to the inferior turbinate at the sphenoethmoidal recess floor
- D Within the frontal recess, medial to the uncinate process
Correct answer: A. Medial to the superior turbinate, approximately 1.5 cm above the choana
Explanation
The sphenoid ostium opens into the sphenoethmoidal recess, lying medial to the superior or supreme turbinate and roughly 1.5 cm above the choana, a distance useful when navigating without image guidance. The sphenoethmoidal recess drains the sphenoid, so the ostium is never found in the middle meatus or frontal recess. Entering the sphenoid too laterally risks carotid and optic nerve injury, hence the medial landmark matters.
Reference: Gray's Anatomy / Stammberger, Functional Endoscopic Sinus Surgery, 42nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.