Atherosclerosis is characterized by the thickening of the inner lining of arteries due to the accumulation of fatty deposits (lipid granules). The granules are deposited between the lining layers via the network of small blood vessels that supply large blood vessels (vasa vasorum).

A continuing buildup of fat globules, first appearing as fatty streaks, then as calcified plaques, leads to hardening of arteries. The complications which result from this condition are among the leading causes of death.