Definition: Diseases of the fourth cranial (trochlear) nerve or its nucleus in the midbrain. The 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. Clinical manifestations include weakness of the superior oblique muscle which causes vertical DIPLOPIA that is maximal when the affected eye is adducted and directed inferiorly. Head tilt may be seen as a compensatory mechanism for diplopia and rotation of the visual axis. Common etiologies include CRANIOCEREBRAL TRAUMA and INFRATENTORIAL NEOPLASMS.
neopl: coord IM with CRANIAL NERVE NEOPLASMS (IM) + histol type of neopl (IM)
Other names Trochlear Nerve Disorder; Trochlear Nerve Disease; Superior Oblique Myokymias; Palsy, Trochlear Nerve; Palsy, Fourth Nerve; Palsies, Trochlear Nerve; Palsies, Fourth Nerve; Neuropathy, Trochlear; Neuropathies, Trochlear; Myokymias, Superior Oblique; Myokymia, Superior Oblique; Fourth Nerve Palsies; Trochlear Neuropathy; Trochlear Nerve Palsy; Trochlear Nerve Disorders; Superior Oblique Palsy, Neurogenic; Superior Oblique Myokymia; Neurogenic Superior Oblique Palsy; Fourth Nerve Palsy; Fourth Cranial Nerve Palsy
