Ipsilateral facial weakness in upper medullary infarction-supranuclear or infranuclear origin?

We describe two patients with upper medullary infarctions showing ipsilater al facial weakness and relative sparing of the upper facial muscles. Electr ophysiological follow-up using transcranial magnetic stimulation of the mot or cortex in combination with stimulation of the peripheral facial nerve di sclosed a supranuclear (corticofacial) tract lesion in one patient and a pa rtial nuclear/infranuclear intra-axial facial nerve lesion in another.