Abstract Background The primitive trigeminal artery (PTA) is the most commonly described fetal anastomosis between the carotid and vertebrobasilar circulations.Case presentation We report chicago cubs earrings a 42-year-old patient presenting with internal carotid dissection, and imaging features of new belial model 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.