This four-stage cross section of an artery demonstrates atherosclerosis, in which the narrowing of the artery is due to a build up of fatty tissue (cholesterol) and plaque. The four stages include: normal artery, fatty streak, fibrous plaque, and blockage. The stages cause a decrease in blood flow, which can lead to a blood clot or thrombus. All stages rotate on a hinge pin. Each model measures 3-1/2" x 1-3/8" dia. Grade 6 and up.