Thoracolumbar spinal cord perfusion depends on a discontinuous and highly variable pattern of segmental arterial reinforcement, particularly through anterior radiculomedullary arteries such as the artery of Adamkiewicz. Although the artery of Adamkiewicz is classically regarded as the principal anterior radiculomedullary contributor to the lower thoracic cord and lumbosacral enlargement, ischemic risk during thoracolumbar surgery cannot be explained by single-vessel anatomy alone. Rather, spinal cord perfusion is maintained through an integrated collateral network in which vulnerability is shaped by the number, distribution, laterality, and timing of segmental arterial interruption. This narrative review synthesizes the clinical anatomy of thoracolumbar radiculomedullary and radiculopial arteries and their relevance to surgical risk. We also examine the collateral network concept, the limitations of the single-artery paradigm, and the role of preoperative vascular localization using computed tomography angiography, magnetic resonance angiography, and digital subtraction angiography. Particular attention is given to high-risk surgical scenarios, including anterior or lateral thoracolumbar approaches, multilevel segmental artery ligation, corpectomy, deformity correction, and oncologic resection. By translating anatomical variability into practical surgical risk zones, this review provides a clinically oriented framework for preoperative planning, approach selection, and intraoperative vascular management in thoracolumbar spine surgery.