The spinal cord drains via the single anterior spinal vein and single posterior spinal vein which in turn drain into the internal vertebral venous plexus located in the epidural space within the extradural fat. Branches from the internal iliac arteries supply the lumbosacral spinal cord. Of note, the artery of Adamkiewicz delivers vascular supply a large area of the thoracolumbar region and thus is considered a watershed area. The artery of the Adamkiewicz (AKA) branches off the left side of the descending aorta around T8 to L2 (via lumbar or intercostal arteries) and connects on the ventral side of the spinal cord to supply the anterior spinal artery. The largest segmental medullary artery is the artery of Adamkiewicz also known as the greater anterior radiculomedullary artery. Segmental spinal arteries supply the mid-thoracic region (T3 to T9) as they come off usually the posterior intercostal artery. The lower cervical to the upper thoracic spinal cord is supplied by radiculomedullary arteries arising from the cervicothoracic trunk C7 to T1 (either left or right). The mid cervical spinal cord receives vascular supply by segmental medullary arteries coming from directly off the vertebral artery. The two anterior spinal arteries primarily supply the upper cervical spinal cord as they come off the vertebral arteries before they anastomose together into the single ASA. There are thought to be anywhere from 8 to 10 in every person. Sometimes, however, the spinal segmental arteries also give off segmental medullary arteries which directly feed into the anterior spinal artery and posterior spinal arteries, however, the numbers differ between person to person. Theoretically there should be 31 radicular arteries for each foramen that receives an artery, but in reality, there is always less. Not only can they supply the ASA/PSA but also provide blood supply to the nerve roots along which they track. The segmental arteries then bifurcate into an anterior and posterior radicular artery which feed into both anterior and posterior spinal arteries respectively. These additional arteries are called segmental spinal arteries. The anterior spinal artery and PSA are fed additional arteries throughout their course down the spinal cord at each spinal level through the intervertebral foramen. The ASA provides blood to the anterior two-thirds of the spinal cord, and the PSA delivers blood to the posterior one-third of the spinal cord. The posterior spinal arteries can branch off the posterior inferior cerebellar artery (PICA) or branches from the pre-atlantal vertebral arteries which also travel caudally down the spinal cord but through the two posterior sulci. However, before joining together to become the basilar artery, the vertebral arteries each give off a branch which becomes the anterior spinal artery the anterior spinal artery travels caudally down the spinal cord through the anterior sulcus. The vertebral arteries pass through the transverse foramen of C1 through C6 and through the foramen magnum to become the basilar artery. The anterior spinal artery is formed by the vertebral arteries which originate from the first part of the subclavian artery. The main blood supply to the spinal cord is via the single anterior spinal artery (ASA) and the two posterior spinal arteries (PSA). The vertebral blood supply for the spinal cord comes from many different sources in the body depending on the region.