Spinal cord blood supply

Spinal cord

infarction presenting as Brown-Séquard syndrome from spontaneous vertebral artery dissection: a case report and literature review. Spinal cord arerial supply. The arteries supplying the spinal cord include the anterior spinal artery (ASA), the posterior spinal artery (PSA), and the radicular artery. The upper region (C1-T2 segments) of the spinal cord is supplied mainly by the vertebral artery. Starting at the level of C3, the anterior and posterior spinal arteries receive a branch from the vertebral artery, that of the radicular artery. In our case, the basic lesion of this patient is the occlusion of the cervical radicular artery caused by vertebral artery dissection, which eventually resulted in right spinal cord infarction

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The spinal cord blood supply is formed by many different vessels with an extensive collateral supply and drainage.

Arterial supply

The spinal cord is supplied by three longitudinal arteries:

single anterior spinal artery: supplies the anterior two-thirds of the spinal cord
- sizable and formed by branches from the intrathecal vertebral arteries
paired posterior spinal arteries: supply the posterior one-third of the spinal cord
- small caliber, often appearing discontinuous

Inferiorly the anterior and posterior spinal arteries join as the cruciate anastomosis of the conus medullaris .

The anterior and posterior spinal arteries are connected by pial anastomoses called the arterial vasocorona which encircles the cord and supplies the peripheral lateral aspect of the spinal cord.

The entire blood supply to the cord is reinforced by numerous radicular or segmental medullary arteries, which from superior to inferior are branches of the :

These arteries pass through the intervertebral foramina and divide into anterior and posterior radicular arteries and have variable anastomoses with the spinal arteries.

The dominant segmental artery is called the artery of Adamkiewicz, which can have a variable origin and side but is typically left-sided and arises between T9 and L2 . Damage to this vessel can cause paralysis from spinal cord infarction as it is the dominant supplier to the lumbosacral cord segments .

In the setting of hypoperfusion, the cord can undergo watershed infarction. As a result of this variable collateral supply, this is variably located but typically in the mid to lower thoracic cord .

In the event of arterial supply being interrupted from the aorta (e.g. surgery, trauma) collateral arterial flow can come from the internal thoracic and lateral thoracic arteries, which anastomose with the posterior intercostal arteries.

Venous drainage of the spinal cord (and vertebrae)

intramedullary venous network: centripetally arranged venous network extending to the cord surface
extramedullary venous network
- six longitudinal channels organized in a loose-knit plexus
- anterior and posterior mid-line longitudinal vein and on each side a pair of longitudinal veins posterior to the nerve roots
radiculomedullary veins
- links intramedullary and extramedullary (internal and external) venous plexuses
- runs a similar course as radiculomedullary arteries
vertebral venous plexus: highly anastomotic network of valveless veins running from the foramen magnum to the sacral hiatus
internal vertebral venous plexus
- consists of anterior and posterior internal vertebral venous plexus in the epidural space
  - anterior internal epidural plexus
    - two anterior interconnecting longitudinal vessels
    - more prominent, lies posterior to the vertebral bodies
  - posterior internal epidural plexus
    - two posterior interconnecting longitudinal vessels
    - less prominent - lies anterior to the lamina
- segmentally receives drainage from radiculomedullary veins and basivertebral veins, and also Batson venous plexus
- communicates above with occipital and basilar sinuses
- drains into intervertebral veins then to vertebral, intercostal, lumbar, lateral sacral veins
external vertebral venous plexus
- in communication with the internal vertebral venous plexus and basivertebral veins via the intervertebral veins which run through the intervertebral foramina
- consists of anterior (anterior to the vertebral bodies) and posterior (posterior to the ligamentum flavum) external vertebral venous plexuses surrounding the vertebral column
- drains into cervical, azygos, ascending lumbar and lateral sacral
basivertebral veins
- runs horizontally within vertebral bodies
- receives drainage from numerous small venous channels
- drains into the anterior external vertebral venous plexus (anteriorly) and anterior internal vertebral venous plexus (posteriorly)