Four major blood vessels supply your brain with blood to provide it with essential nutrients and oxygen, There are the two carotid arteries in the front of your neck and the two vertebral arteries running up protective bony canals in the neck section of your spine, These major arteries join to form the brain’s vascular system, a roughly circular arrangement at the base of your brain. Branches from the circle supply blood to all its parts. Areas that depend on only a single branch are especially vulnerable to any disturbance in the flow of blood.The following articles deal with the principal ways in which the brain can be affected by defects in this system. These disorders, such as stroke, which are caused by inadequate blood supply or by bleeding in the brain tissue from diseased arteries, are serious ailments often marked by dramatic life-threatening attacks. Professional care is urgently needed for anyone who has an attack of this kind.