The authors describe two cases admitted following head injury and presenting with a dilated, stiff pupil. CT scan of the head revealed no intracranial mass lesion. The symptoms persisted over a year in one case, whereas in the other one they faded away within a few weeks. The symptoms are believed to arise due to a downward shift of the brainstem which is known to occur at the moment of head injury. The oculomotor nerve is ++over-stretched and is supposed to be partially damaged at the posterior petroclinoid ligament. The roots of the pupillomotor fibers may also be supposedly torn at the site where they leave the brainstem.