Paralysisof 3rd, 4th, 6th nerves with involvement of ophthalmicdivisionof5thnerve, localizes the lesion to
Apex of orbit
Brainstem
Cavernous sinus
Base of skull
Ipsilateral ophthalmoplegia  causing diplopia occur due to 3rd, 4th  & 6th cranial nerves.
6th nerve passes through cavernous sinus and others are related to the lateral wall of cavernous sinuses.