Which cranial nerve passes through the cavity of the cavernous sinus itself, making it the earliest nerve affected in cavernous sinus thrombosis or internal carotid aneurysm?

• A Abducent nerve (CN VI) ✓
• B Trochlear nerve (CN IV)
• C Oculomotor nerve (CN III)
• D Ophthalmic nerve (V1)

Explanation

The abducent nerve (CN VI) is the only cranial nerve that traverses the cavity of the cavernous sinus itself, running inferolateral to the internal carotid artery, making it directly exposed to sinus pathology and the first nerve affected. CN III, CN IV, V1, and V2 lie within the lateral dural wall of the sinus, so they are affected later as pathology expands.

Reference: Gray's Anatomy, 42nd ed.

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Written and medically reviewed by the StethoPrep medical team.