The longest cranial nerve :

D i.e., vagusVagus (Xth) Cranial nerve has the longest and varied area of supply.The trigeminal (V, fifth) is the largest & thickest cranial nerve.The trochlear nerve is the smallest nerve in terms of the number of axons it contains. The trochlear nerve has the greatest intracranial length.The olfactory nerve is the shoest of the twelve cranial nerves Abducent nerve has the longest intra-cranial INTRADURAL course