A tear within the wall of any of the arteries of the neck (carotid artery or vertebral artery) and that allows blood to separate the wall layers. By separating a portion of the wall of the artery (a layer of the Tunica intima or tunica media), a dissection creates two lumens or passages within the vessel, the native or true lumen, and the "false lumen" created by the new space within the wall of the artery. The disease is MONDO_0006061 (cervical artery dissection).