The spinal cord blood supply is formed by many different vessels with an extensive collateral supply and drainage.
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 4.
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 5:
- posterior inferior cerebellar arteries
- vertebral arteries
- ascending cervical arteries
- deep cervical arteries
- posterior intercostal arteries
- lumbar arteries
- lateral sacral arteries
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 5. Damage to this vessel can cause paralysis from spinal cord infarction as it is the dominant supply to the lumbosacral cord segments 5.
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 5.
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 largely follows the arterial supply. That is, there are anterior and posterior spinal veins and anterior and posterior radicular veins, which freely communicate with the internal vertebral plexus in the epidural space. This, in turn, drains to the cerebral dural venous sinuses and cerebral veins as well as the external vertebral plexus. The veins of the spinal cord and vertebral column are valveless.
- 1. Spinal Cord Medicine. Demos Medical Publishing. ISBN:1933864192. Read it at Google Books - Find it at Amazon
- 2. Neuroscience. Sinauer Associates Inc. ISBN:0878937420. Read it at Google Books - Find it at Amazon
- 3. Greenstein B. Color atlas of neuroscience. Georg Thieme Verlag. ISBN:3131081716. Read it at Google Books - Find it at Amazon
- 4. R. Shane Tubbs, Marios Loukas, Mohammadali M. Shoja. Bergman's Comprehensive Encyclopedia of Human Anatomic Variation. (2016) ISBN: 9781118430354
- 5. Kunam VK, Velayudhan V, Chaudhry ZA, Bobinski M, Smoker WRK, Reede DL. Incomplete Cord Syndromes: Clinical and Imaging Review. (2018) Radiographics : a review publication of the Radiological Society of North America, Inc. 38 (4): 1201-1222. doi:10.1148/rg.2018170178 - Pubmed
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