Anterior spinal artery

Last revised by Arlene Campos on 11 Jan 2024

The anterior spinal artery supplies the anterior portion of the spinal cord and arises from the vertebral artery (V4, intradural segment) in the region of the medulla oblongata. The two vertebral arteries (one of which is usually bigger than the other) anastomose in the midline to form a single anterior spinal artery at the level of the foramen magnum.

It descends along the anterior surface of the spinal cord, within the anterior median fissure and is covered by pia mater, which creates a sheath (linea splendens). Along its course, it is reinforced by other branches that enter the spinal canal via the intervertebral foraminae. Although communication exists at multiple levels, the supply of the cord can be thought of as occurring in three relatively separate sections, supplied by somewhat predictable feeders 4.   

The anterior spinal artery communicates sporadically with the posterior spinal arteries via a pial plexus that encases the cord. At most levels it gives off a sulcal artery which enters the anterior median fissure. 

It terminates inferiorly by forming the cruciate anastomosis of the conus medullaris with the posterior spinal arteries 5.

See spinal cord blood supply.

Variation of the anterior spinal artery origin include 6:

  • duplication, or two independent anterior spinal arteries

  • single origin of anterior spinal artery from unilateral vertebral artery

  • single or duplicate anterior spinal arteries arising off vascular arcade between vertebral arteries

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