Updated November 09, 2008.

Definition: Atherosclerosis is a disease of the arterial blood vessels (arteries), in which the walls of the blood vessels become thickened and hardened by "plaques." The plaques are composed of cholesterol and other lipids, inflammatory cells, and calcium deposits.

The plaques can slow the flow of blood through the arteries, and if the plaques rupture, the blood flow can become completely obstructed.

Also Known As: Arteriosclerosis, Hardening of the Arteries, Atherosclerotic Plaque