Weber syndrome first described by Hermann Weber in a 52-year-old male with left third nerve palsy and right hemiplegia due to a bleed in the left cerebral peduncle.
It is a midbrain stroke syndrome, also called superior alternating hemiplegia.
Characterized by ipsilateral third nerve palsy and contralateral hemiparesis.
Commonly due to occlusion of a branch of the posterior cerebral artery.
Oculomotor nerve arises from two nuclei:
Main motor nucleus: controls extraocular muscles (except lateral rectus and superior oblique) and levator palpebrae superioris.
Accessory parasympathetic nucleus (Edinger-Westphal): controls pupil constriction and lens accommodation.
Lesions can result in partial or complete third nerve palsy, with or without pupillary involvement depending on lesion location within the midbrain.
