Why does a blood clot form in a blood vessel or heart chamber?
A blood clot can form if platelets stick to a patch (plaque) of atheroma. • Platelets are tiny particles in the blood which help the blood to clot when a blood vessel (an artery or vein) is cut. • Atheroma plaques are like fatty lumps that develop within the inside lining of arteries. • Platelets sometimes stick onto an atheroma plaque inside an artery and form a clot. A common site for atheroma to develop, and a blood clot to form, is in a large artery in the neck. A blood clot may also form as a complication of some heart conditions. For example, people with a condition called ‘atrial fibrillation’ have a turbulent (rough) flow of blood in the heart which may cause a small blood clot to form.
