Question

Regarding Weber's syndrome, which of the following is incorrect?

• A. Contralateral hemiplegia
• B. Ipsilateral oculomotor nerve palsy
• C. Contralateral parkinsonism
• D. Anterior cerebral peduncle

Hint:

The lesion is the midbrain crus cerebri, not an 'anterior cerebral peduncle'.

Answer 1

The Correct Option is D

Step 1: Weber's syndrome (superior alternating hemiplegia) is a midbrain stroke caused by occlusion of paramedian branches of the posterior cerebral artery or basilar bifurcation perforators. The lesion sits in the midbrain and involves the cerebral peduncle (crus cerebri) and the exiting oculomotor (third nerve) fibres.
Step 2: Classic features are an ipsilateral third nerve palsy (drooping eyelid, eye down and out, dilated fixed pupil) plus contralateral hemiplegia. Substantia nigra involvement can add contralateral parkinsonism. So the hemiplegia, the third nerve palsy and the parkinsonism statements are all correct.
Step 3: The incorrect statement is the one naming the anterior cerebral peduncle. The structure involved is the midbrain cerebral peduncle (crus cerebri), and there is no entity called the anterior cerebral peduncle as the lesion site. Hence the false option is the anterior cerebral peduncle.