The case of a female patient presenting a complete unilateral ophthalmoplegia secundary to a septic aneurysm of the internal carotid artery is reported. The possible existence of an extravascular infectious etiology in view of the presence of trombophlebitis of the cavernous sinus is discussed. Pertinent reports from the literature are reviewed and the rarity of the phenomenon is commented. The indication for internal carotid artery ligation as a form of treatment deserves further observations.