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April 1992

The Upgoing Thumb Sign

Author Affiliations

Department of Clinical Neurological Sciences The University of Western Ontario University Hospital PO Box 5339 London, Ontario Canada N6A 5A5

Arch Neurol. 1992;49(4):346. doi:10.1001/archneur.1992.00530280026009

To the Editor.  —I have noticed that patients with corticospinal tract involvement of the upper limb when asked to extend their arms, palms facing each other, display an upgoing thumb sign as shown in the Figure.