<prompt> All of them are true about the 4th nerve EXCEPTThe only nerve to emerge from the dorsal aspect of brainThe only nerve to cross over to opposite sideIt is the thickest cranial nerveIt has the fewest axons of any cranial nerve  <response>: The trochlear nerve has several features that make it unique from the other cranial nerves: Thinnest cranial nerve. Is the only nerve to exit from the dorsal surface of the brain. Is the only nerve in which all the lower motor neuron fibers decussate. Has the longest intracranial course. Has the smallest number of axons. 