NEET PG Medical – 2018 – Question – 5

Correct Answer – D
Answer – D. Anterior cerebral peduncle
Weber’s syndrome (superior alternating hemiplegia) is a form of stroke characterized by the presence of an ipsilateral oculomotor nerve palsy and contralateral hemiparesis or hemiplegia.
It is caused by midbrain infarction as a result of occlusion of the paramedian branches of the posterior cerebral artery or basilar bifurcation perforating arteries.
This lesion is usually unilateral and affects several structures in the midbrain:
Contralateral parkinsonism because its dopaminergic projections to the basal ganglia innervate the ipsilateral hemisphere motor field, leading to a movement disorder of the contralateral body.
Contralateral hemiparesis and typical upper motor neuron findings.
It is contralateral because it occurs before the decussation in the medulla.
Difficulty with contralateral lower facial muscles and hypoglossal nerve functions.
Ipsilateral Oculomotor nerve palsy with a drooping eyelid and fixed wide pupil pointed down and out. This leads to diplopia.