Isolated proximal leg paresis due to a small cortical infarction.

We describe two patients with small cortical infarcts, who presented with isolated proximal weakness in one of their legs. These lesions were located in the contralateral precentral gyrus, more medial than the precentral knob, but more lateral than the topmost part of the motor cortex. These clinical findings are consistent with the physiological findings of Penfield and Boldrey, and those of recent activation studies by functional MRI. It is clinically important to pay close attention to the contralateral top of the motor cortex when examining pure motor monoparesis of a proximal part of a lower extremity.