ABSTRACT
Arterial dissection occurs when intraluminal blood penetrates the vessel wall, usually through a tear in the intima, and extends through and between the tissue layers of which the wall is comprised. Dissections occurring in the head and neck may involve either the internal carotid or vertebral arteries (VAs), and may affect either the extradural or intradural portions of the vessels. Dissections involving the extradural portions of the internal carotid artery (ICA) and vertebral artery (VA) are more common than intradural dissections, with extradural ICA dissection occurring more commonly than that of the VA. Conversely, among intradural dissections, involvement of the VAs is considerably more common than dissections of the ICA or its intracranial branches.
