The spine and the spinal cord receive blood from the network of arterial anastomoses, from the direct or indirect blood vessel connection of the spinal branching system. The anterior and posterior spinal arteries are the main blood vessels, which extend longitudinally along the anteromedial and posterolateral surface of the spinal cord. They are supplied with arterial blood by a number of radicular and radiculomedullary arteries arising from spinal arterial branches of the posterior ramus of segmental arteries. These vessels enter intervertebral foramina and pass by the roots of the spinal nerves. The lower thoracic and the upper lumbar region is supplied respectively by the great anterior radicular artery (artery of Adamkiewicz). Central and perforating arteries, terminal branches from both the anterior and posterior spinal artery, form an anastomosing pial arterial plexus for parenchymal blood supply.