A patient with actinomycosis, involving the meninges and right cavernous sinus, presented with diplopia due to a total right external ophthalmoplegia and left abduction weakness. These was partial right ptosis but the pupils were spared. The diagnosis was made by biopsy of a neck mass. A complete recovery was made in response to intravenous penicillin.
Oculomotor palsy secondary to a berry aneurysm is usually present with pupillary dilatation, followed by other signs of third cranial nerve dysfunction, including oculomotor paresis and ptosis. Partial paralysis of the nerve with pupil sparing has been observed, but ptosis as the sole sign of oculomotor paralysis has not previously been reported until now.