While dissection of the carotid and vertebral arteries accounts for only 2% of strokes (which are usually caused by high blood pressure and other risk factors, and tend to occur in the elderly), they cause 10–25% of strokes in young and middle-aged people.Dissecting aneurysms of the vertebral artery constitute 4% of all cerebral aneurysms, and are hence a relatively rare but important cause of subarachnoid hemorrhage. History
Spontaneous vertebral artery dissection was described in the 1970s. Prior to this, there had been isolated case reports about carotid dissection. In 1971, C. Miller Fisher, a Canadian neurologist and stroke physician working at Massachusetts General Hospital, first noted the "string sign" abnormality in carotid arteries on cerebral angiograms of stroke patients, and subsequently discovered that the same abnormality could occur in the vertebral arteries. He reported the discovery in a paper in 1978.

Notable cases
Australian cricketer Phillip Hughes died on 27 November 2014 after developing a vertebral artery dissection as a result of being struck on the side of the neck by a cricket ball during a Sheffield Shield match on 25 November 2014. The ball struck Hughes on the base of the skull just behind his left ear which caused a vertebral artery dissection complicated by subarachnoid hemorrhage. References
External links
Cervical Artery Dissections and Ischemic Stroke Patients, international research collaboration into cervical artery dissection

See also
Aortic dissection
Carotid artery dissection
Heat edema is a cutaneous condition characterized by dependent edema from vasodilatory pooling. Heat causes the blood vessels to expand (dilate), so body fluid moves into the hands or legs by gravity. The balance of salt in the body is also a risk factor for heat edema. If salt loss is less than normal, the increased salt level draws fluid into the hands and legs. Older adults have an increased risk of heat edema, especially if they have other medical conditions that affect their circulation. People visiting hot climates from colder climates may also have an increased risk of heat edema. See also
Heat illness
List of cutaneous conditions


== References ==