[Persistent primitive trigeminal artery: critical review of the clinical significance].

The authors report three cases of persistence of primitive trigeminal artery with no evidence of a relationship between its presence and any specific clinical syndrome. They discuss embryological aspects and establish the correlation between the presence of this malformation and other intracranial pathologies, such as "tic douloureux" and morphologic alteration of the circle of Willis. A critical review of the literature is also presented.