Raeder's paratrigeminal syndrome.

Three middle-aged patients, 2 of whom are females, with unilateral trigeminal pain and associated isolated oculosympathetic paralysis are presented as characteristic of the benign form of Raeder's paratrigeminal syndrome. Their nonprogressive course is representative of the fact that this syndrome is not likely to be caused by aneurysms or mass lesions, and suggests that neuroradiologic contrast studies are generally not initially required in the investigation of such patients. If atypical features are present, or the pain is protracted, further investigation may be warranted.