BLOOD SUPPLY TO THE SPINAL CORD

• Blood is supplied to the spinal cord via THREE arteries:

1) One Anterior [median] spinal artery

a. Located along the anterior midline of the cord

b. Supplies most (75%) of the arterial blood supply to spinal cord

2) Two smaller Posterior spinal arteries

a. Lie on each side of the cord posteriorly

b. Supplies only 25% of the arterial blood supply to posterior region of spinal cord

• Arteriolar sized vessels from both the anterior spinal & both posterior spinal arteries encircle the spinal cord forming a fine pial plexus —> these vessels constitute the vasocorona.
• The vaso corona provide a limited anastomosis between the longitudinal vessels, however if the major anterior radicular artery is occluded, there will not be sufficient blood supply to the distal two-thirds of the spinal cord

• Various Radicular arteries supply the anterior & posterior spinal arteries along the spinal canal:

Cervical Region:

· spinal arteries receive blood from:

1)vertebral arteries

2)posterior inferior cerebellar arteries

3)segmental branches

Thoracic & Lumbar region

· spinal arteries receive blood from Radicular arteries

· Radicular arteries are the anterior & posterior Radicular branches of the spinal branch of the dorsal branch of the posterior intercostal artery

· In this region, have only a few radicular arteries supplying the cord vessels (ant & post spinal arteries), therefore reserve blood supply is precarious. Between C8 & T9 only two small radicular branches supply this long segment of the cord.

· The arteria radicularis magna (major anterior radicular artery) is the principle arterial blood supply of the lower two-thirds of the spinal cord (usually found between T11 & L3).

K. C. Potger
Copyright © 2001

A: cervical and upper thoracic cord supplied by radicular branches of vertebral, ascending cervical, and superior intercostal arteries.

B: watershed.

C: midthoracic cord supplied from a single intercostal artery.

D: thoracolumbar region supplied by a large vessel near diaphragm, and cauda equine supplied from lower lumbar, iliolumbar, and lateral sacral