Aberrant regeneration of the third nerve (oculomotor synkinesis).

Aberrant regeneration of a third nerve palsy (oculomotor synkinesis) excludes an ischaemic cause and in the absence of relevant trauma strongly suggests a compressive aetiology. A scan is mandatory in such cases. We describe the case of a 52-year-old woman who presented with complete pupil-involving third nerve palsy from a posterior communicating artery aneurysm, who later developed widespread aberrant regeneration of pupil, eyelid and third nerve territory rectus muscles.