Stenosis of the carotid artery
A narrowing or blockage of a part of the internal carotid artery can usually occur for two reasons. Either a blood clot has detached and led to an embolism (vascular occlusion) or the vessel has undergone arteriosclerotic changes and over time a thrombus has formed at this site. Most blood clots that lead to a vascular occlusion in the brain come either from the left atrium of the heart (for example as a result of valve disease) or from the carotid bifurcation.
These clots enter the brain with the blood flow and settle in the places where they cannot move because of the small diameter of the blood vessels. The A. cerebri media is most frequently affected. The occlusion of a vessel leads to circulatory disorders and thus to a lack of oxygen and nutrients in the area no longer supplied.
This ultimately leads to a so-called stroke. Those affected often have neurological failures of various kinds. Typical symptoms are paralysis, speech disorders, loss of visual field or numbness in parts of the body.