Caroti stenosis is a narrowing of the lumen of the carotid artery, usually caused by atherosclerosis. The unqualified term "carotid stenosis" in common medical usage refers to the stenosis in the proximal part of the internal carotid artery (at the carotid bulb), as this is the by far the most common site of stenosis within the carotid arteries. Stenosis in other parts of the carotid arteries does occur.