A 57-year-old man with carcinoma of the right maxillary sinus reports numbness over the posterior half of his hard palate on the same side, while sensation over the cheek remains intact. CT demonstrates tumour extension along the palatine canal. Which nerve is involved?

• A Infraorbital nerve
• B Superior alveolar nerve
• C Greater palatine nerve ✓
• D Zygomaticofacial nerve

Explanation

The greater palatine nerve, a branch of V2, descends in the palatine canal to supply the posterior hard palate and adjacent gingiva, so anaesthesia of the posterior palate with tumour tracking along the palatine canal localises to this nerve. Infraorbital nerve involvement produces cheek and upper lip numbness, superior alveolar branches cause upper tooth numbness, and the zygomaticofacial nerve supplies the malar skin, none of which fits the palatal deficit.

Reference: Gray's Anatomy for Students, 4th ed.

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Written and medically reviewed by the StethoPrep medical team.