has part has part characteristic of part of inheres in part of has modifier Cranial nerve paralysis Fourth cranial nerve palsy UMLS:C0271375 HP:0007011 Paralysis of the fourth cranial (trochlear) nerve manifested as weakness of the superior oblique muscle which causes vertical diplopia that is maximal when the affected eye is adducted and directed inferiorly. Trochlear nerve palsy SNOMEDCT_US:20610004 The fourth cranial nerve crosses as it exits the midbrain dorsally and may be injured along its course through the intracranial space, cavernous sinus, superior orbital fissure, or orbit. abnormal paralysed trochlear nerve