Oculomotor fascicular syndrome involving the right superior rectus and theinferior oblique muscles

We report a case of partial oculomotor palsy due to a brainstem infarction. A 70-year-old female noted a sudden onset of double vision. Visual acuity was normal in both eyes. Pupils were round and isocoric. The right eye was hypotropic and showed an elevation deficit. Bell's phenomenon was not evide nt in the right eye. MRT showed a low intensity on the TI-weighted image an d a high intensity on the Ta-weighted image in the right ventrolateral port ion of the mesencephalon. The partial oculomotor paresis of this case refle cts damage of the oculomotor nerve fascicles that, supply the inferior obli que and superior rectus muscles. We diagnosed the case as right oculomotor fascicular syndrome. This case report also suggests that acquired monocular elevation paresis can be caused by a lesion in the midbrain.