A fibrous plaque is a thickened, fibrous lesion formed by the accumulation of collagen and smooth muscle cells within the arterial intima, typically as part of atherosclerotic plaque development. It is clinically significant because it contributes to arterial narrowing and reduced blood flow, increasing the risk of ischaemic events. A common complication associated with fibrous plaques is the potential for plaque rupture, which can trigger thrombosis and lead to myocardial infarction or stroke.