Circulatory deficit in the territory of the vertebral arteries and the basilar trunk, almost always due to stenosing and thrombosing atheromatous lesions. Its symptoms are occipital headache, loss of balance, visual disorders (amaurosis, perception of bright spots or lines) or motor (leg weakness), episodes of drowsiness or amnesia, hearing, cerebellar, sensory disorders, dysarthria, etc. It can lead to chronicity due to permanent circulatory failure, or to thrombosis with softening.

Treatment: Additional damage to the blood vessels must be reduced and the risk of stroke reduced, lifestyle changes and medical treatment if the narrowing of the arteries and symptoms are not severe: a) Anti-hypertensive drugs b) Statins to lower the level of low-density lipoprotein (LDL) cholesterol in the blood. c) anticoagulant to reduce blood clotting ability d) stop smoking e) eat a healthy diet f) exercise regularly. In more severe cases, angioplasty and vascular endoprostheses are used.