The piriform fossa (piriform recess) in the laryngopharynx is an important site for lodgment of foreign bodies. Which nerve runs in the mucosa of the piriform fossa and can cause referred otalgia when involved by hypopharyngeal carcinoma?
- A Internal laryngeal nerve (branch of superior laryngeal nerve, from CN X) ✓
- B Glossopharyngeal nerve (CN IX)
- C Hypoglossal nerve (CN XII)
- D Lingual nerve (from CN V3)
Correct answer: A. Internal laryngeal nerve (branch of superior laryngeal nerve, from CN X)
Explanation
The internal laryngeal nerve (sensory branch of the superior laryngeal nerve, a branch of CN X/vagus) provides sensory innervation to the laryngopharynx mucosa, including the piriform fossa, and enters the larynx through the thyrohyoid membrane. Referred otalgia in hypopharyngeal carcinoma results from vagal irritation and its auricular branch (Arnold's nerve) referral to the ear. The close anatomical relationship of the internal laryngeal nerve to the piriform fossa mucosa makes it the key nerve in this area.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.