Answer
Answer 19-4. Emboli arise from arteries, heart and aorta.A major percentage are caused by embolism of clot/atheromatous material from atherosclerotic plaques in the aorta, carotids or vertebrobasilar arteries. Cardiac sources include atrial fibrillation, severe valvular disease (including endocarditis), congestive heart failure (or ventricular dyskinesia, with pooling and clotting of blood), or recent myocardial infarction. Emboli may also pass from the venous side to the arteries via right to left shunts (such as a patent foramen ovale).