Anesthesia · single question
After performing an inferior alveolar nerve block, the patient returns with facial PARALYSIS on the same side. Which nerve was inadvertently anesthetized?
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Correct answer: C. Facial nerve (CN VII)
Facial paralysis (motor deficit — cannot close eye, face droops) after IAN block = facial nerve (CN VII) inadvertently anesthetized. Occurs with too-posterior injection into the parotid gland where CN VII branches. Temporary — resolves when anesthetic wears off.
- A. Trigeminal CN V is the target — its anesthesia produces numbness, not paralysis.
- B. Glossopharyngeal CN IX innervates posterior tongue/pharynx — its block causes swallowing difficulty, not facial paralysis.
- C. CORRECT. Facial nerve (CN VII) = facial paralysis. Too posterior injection → anesthetic into parotid → inadvertent CN VII block.
- D. Hypoglossal CN XII = motor to tongue — its block would cause tongue deviation, not facial drooping.