A<unk> is a tear within the wall of a blood vessel, which allows blood to separate the wall layers. Usually, a<unk> is an arterial wall<unk>  but rarely it may be a vein wall<unk> (VWD). By separating a portion of the wall of the artery (a layer of the tunica intima or tunica media), a<unk> 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.
Dissection 
Effacement 
Abutment 
Disarticulation
Prolapse
Fixation 
ConFusion
Exfoliation 