Abstract
BACKGROUND: The primitive trigeminal artery (PTA) is the most commonly described fetal anastomosis between the carotid and vertebrobasilar circulations. CASE PRESENTATION: We report a 42-year-old patient presenting with internal carotid dissection, and imaging features of brainstem infarction. CONCLUSION: Based on the imaging studies we presume occlusive carotid dissection with extensive thrombosis within a persistent trigeminal artery as the cause of this brainstem ischemia.