Isolated hand palsy due to cortical infarction: localization of the motor hand area.

OBJECTIVE: To evaluate the cortical presentation of the hand area according to MRI images of the infarcted area in patients who have predominantly hand weakness.

BACKGROUND: "Pseudoperipheral palsy" is an old term employed to describe a rare clinical picture consisting of predominant weakness of the hand in association with cerebral infarction. Because the organization of the cortical efferent area of the hand has not been fully defined, this phenomenon merits attention. Recent advances in functional imaging have stimulated renewed interest in the cortical mapping of various body parts, particularly that of the hand.

METHODS: The patients who had isolated hand palsy due to cerebral infarction underwent clinical examination and cerebral MRI investigation to locate the exact lesion site.

RESULTS: Eight patients (6 men, 2 women) aged 55 to 80 years (mean 69 years) were included in this study. All had at least one risk factor for cerebrovascular disease. All our 8 patients presented with hand palsy and lesions were detected in the contralateral precentral gyrus in all cases. The lesions were located in the middle to lower portion of the anterior wall of the central sulcus just posterior to the intersection of the superior frontal and precentral sulci.

CONCLUSION: Our findings indicate that the hand area in the cerebral motor cortex is located in the middle to lower portion of the anterior wall of the central sulcus, that is, in Brodmann area 4. We present our 8 patients showing isolated hand palsy due to a discrete cortical infarction on MRI to expand the knowledge about cortical localization of the hand area.