Clinico-anatomical Analysis of the Fibers to the Inferior Rectus Muscle in the Oculomotor Fascicles

Abstract

We report two cases of isolated unilateral pupil-sparing partial fascicular oculomotor paresis. Patient 1 was a 72-year-old man who developed left-sided palsy of the inferior rectus muscle (IR), medial rectus muscle (MR), superior rectus muscle (SR), inferior oblique muscle (IO), and levator palpebrae superioris (LP) due to infarction of the left paramedian thalamic artery. Patient 2 was a 70-year-old woman who developed right-sided palsy of MR, SR, IO and LP due to infarction of the right superior paramedian mesencephalic artery. These results suggest that the fibers to IR may be located in the most rostral portion of the oculomotor fascicles.