Localization of motility abnormalities
| Motility Disturbance | Localization/Etiology |
|---|---|
| Weber syndrome (Third-nerve palsy and hemiparesis) | Anterior midbrain |
| Benedikt syndrome (third-nerve palsy and contralateral tremor) | Red nucleus and third-nerve fascicle |
| Isolated pupil-involving third-nerve palsy | Posterior communicating artery aneurysm |
| Pupil-sparing third-nerve palsy | Microvascular ischemia of the third nerve |
| Isolated fourth-nerve palsy | Doral midbrain/anterior medullary velum |
| Microvascular ischemia | |
| Isolated sixth nerve palsy | Pons or sixth-nerve fascicle |
| Demyelination/microvascular ischemia | |
| Gaze palsy and facial weakness | Dorsal pons/facial colliculus |
| Bilateral sixth-nerve palsies | Elevated intracranial pressure |
| Third-, fourth-, and sixth-nerve palsies | Cavernous sinus |
| Third-, fourth-, sixth-nerve palsies, and optic neuropathy | Orbital apex |
| Multiple cranial neuropathies | Subarachnoid space |
| Internuclear ophthalmoplegia | Medial longitudinal fasciculus |
| Gaze palsy | Dorsal pons |
| Parinaud syndrome (upgaze palsy, eyelid retraction) | Dorsal midbrain |