The chorda tympani nerve crosses the medial surface of the tympanic membrane and leaves the middle ear cavity through which opening?
- A Petrotypanic (Glaserian) fissure ✓
- B Hiatus for the greater petrosal nerve
- C Stylomastoid foramen
- D Foramen ovale
Correct answer: A. Petrotypanic (Glaserian) fissure
Explanation
Chorda tympani arises from the facial nerve in the mastoid segment, enters the middle ear through the posterior canaliculus, crosses the medial aspect of the tympanic membrane over the promontory, and exits through the petrotympanic fissure to join the lingual nerve. It carries taste from the anterior two-thirds of the tongue and secretomotor fibers to submandibular and sublingual glands via the submandibular ganglion. Stylomastoid foramen transmits the main facial trunk after the chorda has branched off.
Reference: Snell Clinical Anatomy by Regions, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.