In a patient with a large cerebellopontine angle vestibular schwannoma, which cranial nerve is MOST commonly involved clinically AFTER the vestibulocochlear nerve itself?

• A Facial nerve
• B Abducens nerve
• C Trigeminal nerve ✓
• D Lower cranial nerves (IX, X)

Explanation

After audiovestibular symptoms, the trigeminal nerve is the next most frequently involved cranial nerve in vestibular schwannoma, producing facial numbness, paraesthesiae and depression of the corneal reflex, because the sensory root lies superiorly in the cerebellopontine cistern adjacent to the tumour. The facial nerve, though stretched over the tumour capsule, is remarkably resistant and palsy is a late sign, which kills option A. Abducens and lower cranial nerve involvement occurs only with very large tumours.

Reference: Scott-Brown's Essential Otorhinolaryngology, 2nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.