Trochlear nerve all true except
Trochlear nerve is thinnest nerve. It is the only nerve to emerge from dorsum of brain stem has longest intracranial course. It enters orbit through outer part of superior orbital fissure (ie lateral to annulus of Zinn) and supplies superior oblique muscle. Because it's a crossed cranial nerve (with decussation in mid brain), the trochlear nerve nucleus supplied contralateral superior oblique muscle.
Longest intracranial course
Arises from dorsum of brainstem
Supplies ipsilateral superior oblique muscles
Enter orbit though sup orbital fissure outside annulus of Zinn.