Nerve potentially injured during tonsillectomy?

• A. Accessory
• B. Vagus
• C. Glossopharyngeal
• D. Hypoglossal

Answer: (C)

Nerve supply to the tonsillar region comes from the glossopharyngeal nerve. Its tonsillar branches travel in the pharyngeal plexus to the palatine tonsil, so this nerve is at risk during tonsillectomy as the surgeon works in the tonsillar bed. Injury to CN IX can affect sensation in the oropharynx and the posterior tongue and can disrupt the afferent limb of the gag reflex.

The other nerves listed are less involved in the tonsillar bed: the accessory nerve supplies neck and shoulder muscles, the vagus nerve runs deeper or more posterior in the wall of the pharynx with branches not specifically dedicated to the tonsillar bed, and the hypoglossal nerve innervates tongue muscles rather than the tonsillar region.