Fenestration of the vertebral artery.
D000792:Angiography; D002648:Child; D006261:Headache / Q000209:etiology; D006801:Humans; D008297:Male; D014653:Vascular Headaches / Q000209:etiology; D014711:Vertebral Artery / Q000002:abnormalities* / Q000000981:diagnostic imaging