The piriform fossa (sinus) is a recess of the laryngopharynx lateral to the aryepiglottic fold. Foreign bodies lodging here or tumours in this region may damage a nerve running in the mucosa of the piriform fossa. This nerve is:

• A External branch of the superior laryngeal nerve
• B Recurrent laryngeal nerve
• C Internal branch of the superior laryngeal nerve ✓
• D Glossopharyngeal nerve

Explanation

The internal branch of the superior laryngeal nerve (sensory to the laryngeal mucosa above the vocal cords and epiglottis) runs submucosally in the floor/medial wall of the piriform fossa. Foreign body impaction or carcinoma in the piriform sinus can injure this nerve, causing ipsilateral loss of laryngeal sensation, loss of the cough reflex, and risk of silent aspiration. The external branch (motor to cricothyroid) runs outside the pharyngeal wall. The RLN lies more inferiorly in the tracheo-oesophageal groove.

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

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Written and medically reviewed by the StethoPrep medical team.