[Central facial weakness due to medullary pyramidal infarction; a case report].

We reported a hypertensive 40-year-old man who developed sudden right hemiparesis, deep sensory disturbance, left hypoglossal nerve palsy, and mild right central facial weakness. MRI of the brain showed an infarct located in the left upper medullary pyramid. Course and connection of the corticobulbar pathway are not well known in human. Recently Cavazos (1996) described a hypothesis that some facial corticobulbar fibers descend caudally ipsilaterally as low as the upper medulla, making a loop before decussating and ascending to the contralateral facial nucleus Contralateral central facial weakness may result from interruption of these descending fibers.