headache, thunderclap

headache, vascular One of a group of headaches felt to involve abnormal sensitivity of the blood vessels (arteries) in the brain to various triggers, resulting in rapid changes in the artery size due to spasm (constriction). Other arteries in the brain and scalp then open (dilate), and throbbing pain is perceived in the head. Migraine headache is the most common type of vascular headache. See also migraine headache.