Following excision of a carotid body tumour, a patient is noted to have deviation of the protruded tongue towards the side of surgery. Which nerve was injured, and which artery crosses it high in the neck at the level where it loops forward?

• A Hypoglossal nerve, crossed by the occipital artery ✓
• B Lingual nerve, crossed by the maxillary artery
• C Internal laryngeal nerve, crossed by the superior thyroid artery
• D Glossopharyngeal nerve, crossed by the ascending pharyngeal artery

Explanation

The hypoglossal nerve descends between the internal carotid artery and internal jugular vein, gives the superior root of ansa cervicalis, then curves forward across the carotid bifurcation, where it is crossed by the occipital artery. Injury causes ipsilateral hemiatrophy of the tongue and deviation towards the paralysed side on protrusion, because the intact genioglossus pushes the tongue across. The lingual nerve is a trigeminal branch and does not cause this pattern.

Reference: Snell's Clinical Anatomy by Regions, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.