Arterial plaque builds up inside the vessel wall itself, not in the center where it would block blood flow. The artery expands outward to accommodate it, like a donut getting thicker. This outward growth means early plaque buildup stays hidden until the wall finally runs out of room to expand.
The blood vessel starts storing that plaque in the vessel wall, so you end up with a pool of cholesterol in the vessel wall, and the whole vessel actually expands outwards. Think of a donut. Okay, you got a donut hole. You got the wall of the donut. What happens when plaque begins to form in the wall? It actually deposits into the wall of the vessel, the donut itself, and what happens is the blood vessel starts storing that plaque in the vessel wall, so you end up with a pool. Of cholesterol in the vessel wall, and the whole vessel actually expands outwards. It doesn't grow inward, at least, at least not initially.
