The major causes of stroke in young adults and children differ from those in older people.1 Dissection of the internal carotid and vertebral arteries in the neck accounts for about a fifth of strokes in the young compared with about 2.5% in older patients.1 Dissection of intracranial blood vessels is rare and has a worse prognosis than extracranial dissections.2 Arterial dissection occurs when blood tracks into the vessel wall along a specific line of cleavage. This may be subintimal, causing luminal narrowing or occlusion, or subadventitial, when a pseudoaneurysm may form. The cause is rarely established and may differ according to the artery affected. The incidence of arterial dissection is increased in patients with fibromuscular dysplasia, migraine, or hypertension; in smokers; and in those taking oral contraceptives. It is commonly associated with trauma or manipulation to the neck. Patients with dissection of the arteries in the neck may …