The process in which the anatomical structure of the trochlear nerve is generated and organized. The trochlear nerve is a motor nerve and is the only cranial nerve to exit the brain dorsally. The trochlear nerve innervates the superior oblique muscle. [ GOC:dgh GOC:dph http://openisbn.com/search.php?q=0838580343&isbn=1/ GOC:cls http://purl.obolibrary.org/obo/go/references/0000021 GOC:jid ]