A 35-year-old woman presents with multiple episodes of sudden onset tinnitus, vertigo, and unilateral hearing loss lasting 20–30 minutes, with full recovery. MRI of the posterior fossa is normal. The endolymphatic hydrops underlying Ménière's disease involves distension of which membranous labyrinth structure?

• A Perilymphatic space (scala vestibuli + scala tympani)
• B Endolymphatic sac and duct
• C Bony labyrinth
• D Semicircular canals and cochlear duct (scala media) ✓

Explanation

Endolymphatic hydrops in Ménière's disease involves distension of the endolymph-containing structures: the cochlear duct (scala media) and the membranous portions of the semicircular canals (utricle, saccule). Excess endolymph causes fluctuating pressure changes leading to episodic vertigo, tinnitus, and low-frequency sensorineural hearing loss. The perilymphatic spaces (scala vestibuli and tympani) are separate CSF-like compartments. The endolymphatic sac normally reabsorbs endolymph — its dysfunction underlies hydrops.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.