Isolated inferior rectus palsy as a result of paramedian thalamopeduncular infarction.

The authors present the cases of two patients with isolated inferior rectus muscle paresis presumed to be caused by paramedian thalamopeduncular infarction that involved supranuclear descending pathways, just before the inferior rectus subnucleus in one patient, and just before subnucleus or fascicular fibers in the other patient. Both patients had no other associated neurologic dysfunction. The lesions that cause isolated inferior rectus palsy in these patients are documented by magnetic resonance findings. Although vascular ischemic lesions as the cause of isolated inferior rectus palsy were reported previously, to the authors' knowledge, it has not been demonstrated radiologically.