Table 3:

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