Which cranial nerve travels closest to the internal carotid artery in the cavernous sinus?

• A. CN III
• B. CN IV
• C. CN V
• D. CN VI

Answer: (D)

In the cavernous sinus, nerve arrangements differ by position relative to the internal carotid artery. The nerves that control most eye movements (oculomotor, trochlear, and the branches of the trigeminal nerve) run in the lateral wall of the sinus, keeping a bit of distance from the artery. The abducens nerve, however, travels along the medial side of the cavernous sinus and lies closest to the internal carotid artery itself. That proximity is why the abducens nerve is the one that travels nearest to the artery here. This nerve specifically innervates the lateral rectus muscle to abduct the eye, so a lesion can cause impaired lateral gaze or inward deviation.