Spontaneous dissection of the carotid and vertebral arteries.

When a tear occurs in one of the major arteries in the neck and allows blood to enter the wall of the artery and split its layers, the result is either stenosis or aneurysmal dilatation of the vessel. This process was long thought to be a rare cause of stroke, particularly in the absence of trauma, and the diagnosis was usually not made until the postmortem examination.1–3 It was not until the late 1970s, when Fisher et al.1 and Mokri et al.2 described dissections of carotid and vertebral arteries as detected by modern diagnostic approaches, that dissections began to . . .