Figure 1a. Drawings illustrate the arteries of the spinal cord and spine. (a) The thoracolumbar segment of the spinal cord is vascularized by branches of the thoracoabdominal aorta via the intercostal and lumbar arteries. (b) The intercostal or lumbar artery arises from the aorta and divides into anterior and posterior branches. The posterior branch subdivides into the radiculomedullary artery, the muscular branch, and the dorsal somatic branch. The radiculomedullary artery further subdivides into the anterior and posterior radiculomedullary arteries. (Fig 1 reprinted, with permission, from reference 18.)