What is the primary cause of an embolic stroke?

An embolic stroke primarily occurs when a blood clot or other debris forms away from the brain—most often in the heart—and travels through the bloodstream to lodge in narrower brain arteries. This blockage prevents blood flow to a part of the brain, leading to tissue damage and potential neurological deficits. The clot itself, often originating from conditions such as atrial fibrillation or heart valve disease, is responsible for the stroke.

While other options present potential causes of neurological issues, they are not the primary mechanisms behind an embolic stroke. The rupture of a blood vessel leads to a hemorrhagic stroke, which differs fundamentally from an embolic stroke. Severe migraines and brain tumors can cause headaches and other neurological symptoms, but they do not result from an embolism and do not directly cause the blockage of blood flow to the brain in the manner described for an embolic stroke. Thus, the focus on the blood clot occluding a blood vessel distinctly identifies the correct answer.