[A case of pure motor isolated finger palsy due to cerebral infarction].

A 73-year-old man, a right-handed, has been pointed out his atrial fibrillation and seen a doctor regularly for varicose veins of left leg and hypertension. He had complaint of a sudden paralysis of his left thumb and index finger while drinking beer. The next day, there was no improvement and he was admitted to our hospital. Neurological examination revealed mild weakness of the most muscles of both thumb and index finger which were innervated by radial nerve, ulner nerve, and median nerve. But he had no any other neurological deficits including sensory system. A brain MRI revealed the acute-stage cerebral infarction in the right precentral knob. With other examinations, we diagnosed the cerebral infarction as cardiogenic embolism. Pure motor isolated finger palsy (PMIFP) in association with cerebrocortical small lesion is rare. It is probable that some cases with diagnosed of peripheral neuropathy was actually PMIFP from central nervous system disturbance.