Question:medium
Regarding Weber's syndrome, which of the following is incorrect?
Regarding Weber's syndrome, which of the following is incorrect?
Show Hint
The lesion is the midbrain crus cerebri, not an 'anterior cerebral peduncle'.
Updated On: Jun 24, 2026
- Contralateral hemiplegia
- Ipsilateral oculomotor nerve palsy
- Contralateral parkinsonism
- Anterior cerebral peduncle
Show Solution
The Correct Option is D
Solution and Explanation
Step 1: Localise Weber's syndrome precisely - it is a ventral (basal) midbrain lesion in the territory of paramedian posterior cerebral artery branches. The damaged structures are the crus cerebri (cerebral peduncle) carrying corticospinal fibres and the fascicles of cranial nerve III passing through it.
Step 2: Because the third nerve is hit before it crosses, the eye signs are ipsilateral: ptosis, mydriasis and a down-and-out eye. The corticospinal fibres are damaged above the medullary decussation, so the weakness is contralateral hemiplegia. Nigral involvement may add contralateral parkinsonism. All three of these match the syndrome.
Step 3: Pick the wrong statement. The lesion is in the cerebral peduncle of the midbrain; the phrase anterior cerebral peduncle is not a valid description of the site. Therefore that option is the incorrect (and so the correct choice for a negatively framed question).
\[\boxed{\text{Anterior cerebral peduncle (incorrect statement)}}\]
Step 2: Because the third nerve is hit before it crosses, the eye signs are ipsilateral: ptosis, mydriasis and a down-and-out eye. The corticospinal fibres are damaged above the medullary decussation, so the weakness is contralateral hemiplegia. Nigral involvement may add contralateral parkinsonism. All three of these match the syndrome.
Step 3: Pick the wrong statement. The lesion is in the cerebral peduncle of the midbrain; the phrase anterior cerebral peduncle is not a valid description of the site. Therefore that option is the incorrect (and so the correct choice for a negatively framed question).
\[\boxed{\text{Anterior cerebral peduncle (incorrect statement)}}\]
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