Unilateral oculomotor palsy and bilateral ptosis from paramedian midbrain infarction.

Lesions of the oculomotor fascicles are localized clinically by associated neurologic deficits. We present two patients with bilateral ptosis, unilateral paresis of all other muscles innervated by the oculomotor nerve, and sparing of the contralateral superior rectus muscle--findings suggesting a lesion of the proximal oculomotor fascicles and the central caudal subnucleus. To our knowledge, these are the first such cases with radiologic confirmation of a lesion within the dorsal, paramedian midbrain.