Cerebrovascular disease capillary bed separates arteries from veins, which protects the veins from the higher blood pressures that occur in arteries. In arteriovenous malformations, arteries are directly connected to veins, which increases the risk of venous rupture and hemorrhage. Arteriovenous malformations in the brain have a 2–4% chance of rupture each year. However, many arteriovenous malformations go unnoticed and are asymptomatic throughout a person's lifetime. A germinal matrix hemorrhage is bleeding into the brain of premature infants caused by the rupture of fragile blood vessels within the germinal matrix of premature babies. The germinal matrix is a highly vascularized area within an
Striate arteries They may either rupture, producing an intracerebral hemorrhage that is initially centered in the region they supply, or they become occluded, producing a lacunar infarct in the tissue they supply. The lenticulostriate arteries are "end arteries", meaning that the regions they supply do not have significant collateral blood supply. Occlusion of these vessels therefore leads to stereotyped stroke syndromes. In the case of the lenticulostriate vessels, hemorrhage may remain localized to the putamen and caudate nucleus, may involve neighboring structures such as the internal capsule and other more distant white matter of the hemisphere, or may even rupture into the