The endolymphatic duct drains endolymph from the membranous labyrinth to the endolymphatic sac, which is located:
- A On the posterior surface of the petrous bone in the epidural space ✓
- B Within the cochlear aqueduct adjacent to the round window
- C In the subarachnoid space adjacent to the internal auditory canal
- D In the perilymphatic space of the scala tympani
Correct answer: A. On the posterior surface of the petrous bone in the epidural space
Explanation
The endolymphatic sac is located on the posterior petrous face of the temporal bone, between the layers of the dura mater (epidural location). It is the site of endolymph resorption and immune function of the membranous labyrinth. Endolymphatic sac decompression surgery targets this structure in Meniere's disease to reduce endolymphatic pressure. The cochlear aqueduct connects perilymph (not endolymph) with the CSF.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.