[Isolated paralysis of the ocular motor nerve caused by infarction of fascicular fibers].

We report the case of an 80 year-old woman who developed an unilateral brainstem infarction with a lesion of the intraparenchymatous fibres of the IIIrd cranial nerve. Intraaxial lesions of this nerve are usually part of the alternate paralysis syndrome. Our case might be the second since the report of Achard and Levi in 1901. Infarction limited to the fascicular fibres of the oculomotor nerve sparing the oculomotor nuclei results in characteristic clinical manifestations. This in turn results from the highly selective distribution of the terminal arterial territories in the midbrain.