The round window niche of the middle ear is closed by which structure, displacement or rupture of which can produce a perilymph fistula with fluctuating sensorineural hearing loss?

• A Secondary tympanic membrane ✓
• B Annular ligament
• C Stapedius tendon
• D Mucosal fold of the niche

Explanation

The round window is closed by the secondary tympanic membrane, a thin two-layered membrane that separates the scala tympani from the middle ear and yields to compensate for stapedial motion at the oval window. Rupture from barotrauma or vigorous straining allows perilymph to leak into the middle ear, causing vertigo and fluctuating hearing loss. The annular ligament seals the oval window, not the round window.

Reference: Dhingra Diseases of Ear, Nose and Throat, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.