<prompt> Trochlear nerve all true except:Longest intracranial courseArises from dorsum of brainstemSupply ipsilateral superior oblique muscleEnter orbit through sup.  <response>: C i.e. Supplies ipsilateral superior oblique muscle Trochlear nerve is thinnest nerve. It is the only nerve to emerge from dorsum of brain stemQ has longest intracranial course. It enters orbit through outer pa of superior orbital fissure ie lateral to annulus of ZinnQ and supplies superior oblique muscle. Because its a crossed cranial nerve with decussation in mid brain, the trochlear nerve nucleus supplies contralateral superior oblique muscle. 