Paralysis of 3rd, 4th, 6th nerves with involvement of ophthalmic division of 5th nerve, localizes the lesion to:
CN III, IV, V1, V2, and VI and postganglionic sympathetic fibers en route to the orbit all pass through the cavernous sinus. Ref:Snell's Clinical Anatomy, 7th Edition, Pages 798-800
Cavernous sinus
Apex of orbit
Brainstem
Base of skull