The endolymphatic sac is located in which anatomical compartment?
- A Within the bony labyrinth of the petrous bone
- B In the internal auditory canal alongside the vestibulocochlear nerve
- C In the posterior cranial fossa dura mater between the posterior surface of the petrous bone and the dura ✓
- D In the mastoid air cells below the tegmen mastoideum
Correct answer: C. In the posterior cranial fossa dura mater between the posterior surface of the petrous bone and the dura
Explanation
The endolymphatic sac is the distal expansion of the endolymphatic duct and lies extradurally (between the posterior surface of the petrous bone and the posterior fossa dura) in a bony groove on the posterior aspect of the petrous pyramid — the endolymphatic fossa. It is responsible for endolymph resorption and immunological functions; endolymphatic sac decompression or shunting is a surgical option for refractory Meniere's disease.
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.