This 4 panel illustration shows the development of an arterial dissection. The first inset shows a normal arterial wall anatomy including the intima, media, and adventitia. The second inset shows the initial tearing of the intima layer of the artery wall. The third inset shows the formation of a thrombus within the dissected flap. The final inset shows a portion of the thrombus breaking off, forming an embolus, and entering the blood flow.