Lacunar stroke occurs when one of the small arteries (iameter: 0.2 － 15mm) that provides blood to the brain's deep structures is blocked and injures deeper structures underneath the cortex. It may be referred to as a Lacunar Infarct (LACI). A patient who presents with the clinical symptoms of a lacunar stroke, but who has not yet had diagnostic imaging performed may be described as suffering from Lacunar Stroke Syndrome (LACS)