Spinal Cord Vascular Supply

The spinal cord is supplied by a longitudinal arterial network derived from the vertebral arteries and reinforced segmentally along its length. A single anterior spinal artery runs in the anterior median fissure and supplies roughly the anterior two-thirds of the cord, while paired posterior spinal arteries supply the posterior columns; both depend on radicular feeder arteries that enter with the nerve roots to maintain flow over the cord's full extent.

Definition

The spinal cord vascular supply comprises the single anterior spinal artery and the paired posterior spinal arteries, together with the segmental radicular and medullary feeder arteries that reinforce them, providing arterial perfusion along the length of the spinal cord.

Scope

This entry describes the arterial supply of the spinal cord: the anterior and posterior spinal arteries, the segmental radicular and medullary feeders, the dominant thoracolumbar feeder known as the artery of Adamkiewicz, and the watershed regions that arise from this segmentally reinforced arrangement. It is a reference description of normal anatomy and is not clinical guidance on spinal cord ischaemia.

Core questions

• Which arteries form the longitudinal supply of the spinal cord, and what part of the cord does each serve?
• How do segmental radicular and medullary feeders reinforce the anterior and posterior spinal arteries?
• What is the artery of Adamkiewicz and why is it anatomically important?
• Where are the watershed regions of the spinal cord that are most vulnerable to reduced perfusion?

Key concepts

• Anterior spinal artery
• Posterior spinal arteries (paired)
• Radicular and segmental medullary feeder arteries
• Artery of Adamkiewicz (great anterior radiculomedullary artery)
• Vasocorona and pial arterial plexus
• Watershed (border-zone) territories
• Anterior two-thirds vs posterior one-third supply

Mechanisms

The anterior spinal artery arises from branches of the two vertebral arteries near the foramen magnum and descends in the anterior median fissure, supplying the anterior horns, the anterolateral tracts, and most of the central grey matter via central (sulcal) branches. The paired posterior spinal arteries supply the dorsal columns and the dorsal horns. Because these longitudinal vessels are too small to perfuse the whole cord on their own, they are reinforced at intervals by radicular arteries that travel with the nerve roots; the largest of these, the artery of Adamkiewicz, usually arises in the lower thoracic or upper lumbar region and is the dominant feeder to the anterior spinal artery in the thoracolumbar cord (nda-2015, romanes-1965). The variable number and position of these feeders create border-zone (watershed) regions, classically in the mid-thoracic cord, where the supply is most tenuous (thron-1988, standring-2020).

Clinical relevance

The anterior two-thirds versus posterior one-third arterial division explains why interruption of the anterior spinal artery produces a different pattern of deficit from posterior involvement, and the segmental feeder anatomy explains the existence of vulnerable watershed levels. This anatomy informs the interpretation of spinal vascular imaging and the planning of aortic and spinal procedures; the descriptions here are educational and not a basis for diagnosing or managing any individual.

Evidence & guidelines

The longitudinal and segmental arrangement is established in classic anatomical injection studies and neuroradiological monographs (romanes-1965, thron-1988, standring-2020), and the microsurgical anatomy of the dominant thoracolumbar feeder has been characterized in dissection studies (nda-2015). This entry summarizes descriptive anatomy and does not constitute a clinical guideline.

History

The segmental reinforcement of the spinal cord's longitudinal arteries was characterized by nineteenth-century anatomists, with Adamkiewicz describing the large thoracolumbar radiculomedullary feeder that bears his name. Twentieth-century injection and neuroradiological studies, including Romanes's quantitative analysis of feeder arteries and Thron's neuroradiological monograph, clarified the watershed pattern and the variability of the supply (romanes-1965, thron-1988).

Key figures

• Albert Wojciech Adamkiewicz
• George John Romanes
• Armin K. Thron

Seminal works

• romanes-1965
• thron-1988
• nda-2015

Frequently asked questions

How is the spinal cord supplied with blood?

By a single anterior spinal artery supplying roughly the anterior two-thirds of the cord and paired posterior spinal arteries supplying the posterior columns, all reinforced at intervals by segmental radicular feeder arteries entering with the nerve roots.

What is the artery of Adamkiewicz?

It is the largest anterior radiculomedullary feeder, usually arising in the lower thoracic or upper lumbar region, and is the dominant reinforcement of the anterior spinal artery in the thoracolumbar cord.