<prompt> Cranial nerve related to apex of petrous temoporal boneVIIIVIIVIIX  <response>: Cranial nerve 5 6 are related to apex of petrous bone.Only 1st 2nd cranial nerves do not arise from brain stem and so do not pass through posterior-cranial fossa. And all other C.N i.e. 3rd to 12th pass through posterior cranial fossa.Trochlear 4th nerve is the only cranial nerve to emerge dorsally from the brain stem has longest infra cranial course and most slender cranial nerve in terms of axons it contains 