Fourth cranial nerve palsy

What it means

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.

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.

Rare diseases that can present with this5

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Trochlear nerve palsy