Ophthalmology Paralysis of 3rd, 4th, 6th nerves with involvement of ophthalmic division of 5th nerve, localizes the lesion A Cavernous sinus. B Apex of orbit. C Brainstem D Base of skull. 💡 Explanation Paralysis of 3rd, 4th, 6th nerves with involvement of ophthalmic division of 5th nerve, localizes the lesion ✓ Correct Answer: A. Cavernous sinus.