The anterior spinal artery is the artery that supplies the anterior portion of the spinal cord. It arises from branches of the vertebral arteries and courses along the anterior aspect of the spinal cord. It is reinforced by several contributory arteries, especially the artery of Adamkiewicz.
The anterior spinal artery arises bilaterally as two small branches near the termination of the vertebral arteries. One of these vessels is usually larger than the other, but occasionally they are about equal in size. Descending in front of the medulla oblongata, they unite at the level of the foramen magnum. The single trunk descends in the front of the medulla spinalis, extending to the lowest part of the medulla spinalis. It is continued as a slender twig on the filum terminale.
On its course the artery takes several small branches (i.e. anterior segmental medullary arteries), which enter the vertebral canal through the intervertebral foramina. These branches are derived from the vertebral artery, the ascending cervical artery, a branch of the inferior thyroid artery in the neck, the intercostal arteries in the thorax, and from the lumbar artery, iliolumbar artery and lateral sacral arteries in the abdomen and pelvis.
The vessel is placed in the pia mater along the anterior median fissure. It supplies that membrane, and the substance of the medulla spinalis, also sending off branches at its lower part to be distributed to the cauda equina.