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The anterior spinal artery (ASA) is the principal longitudinal arterial trunk supplying the anterior 2/3 of the spinal cord, encompassing the anterior horns, corticospinal tracts, and spinothalamic pathways (see Image. Anterior Spinal Artery). This blood vessel typically arises from bilateral rami of the intracranial V4 segments of the vertebral arteries, which fuse near the pyramidal decussation and descend within the anterior median sulcus. Segmental reinforcement occurs via radiculomedullary arteries, with characteristic cervical and thoracolumbar enlargements. Embryologically, the ASA forms from the fusion of paired ventral longitudinal channels derived from the perineural vascular plexus during neurulation, followed by desegmentation of primitive segmental feeders. Common anatomic variants arise from differences in number, caliber, symmetry, and midline fusion of prespinal rami originating from the intracranial V4 segments of the vertebral arteries near the vertebrobasilar junction. Detailed knowledge of ASA anatomy, development, and variants is essential in trauma, aortic and spinal surgery, vertebrobasilar interventions, and spinal angiography. Structural understanding permits accurate radiologic interpretation and risk stratification, and informs prevention, recognition, and management of ASA syndrome and related ischemic complications.