Teaching Neuro Images : A case of partial oculomotor palsy

Abstract

A 68-year-old hypertensive man presented with binocular horizontal diplopia associated with drooping of right eyelid. Examination revealed medial rectus palsy, noncorrectable ptosis of the right eye (figure 1), normal pupils, and no long tract signs. Brain MRI showed a hyperintense T2 signal in the dorsal midbrain and diffusion restriction on diffusion-weighted imaging with corresponding reduced apparent diffusion coefficient (figure 2, A, C, and D). At 2 months, diplopia and ptosis improved significantly. Individual third nerve fascicles in the ventral mesencephalon have a topographic arrangement (figure 2B). 1 The medial rectus fascicle occupies the intermediate position between superior rectus and levator palpebrae superioris. 1,2