The persistent trigeminal artery is the most frequent of the persistent embryonic carotid-basilar artery anastomoses. In the literature, it has most often been described in relation to cerebrovascular pathologies such as aneurysms, vascular nerve compression, trigeminal cavernous fistulas, and thromboembolic ischemia. Its role as collateral circulation, thus supplying brain perfusion during main arterial trunk occlusion, has seldom been described. We describe the case of a patient who presented with a stroke due to a traumatic dissection of the internal carotid artery at the neck, in which the infarction may have been limited by a persistent trigeminal artery.