What is the blood supply to the spinal cord?

Blood supply to the spinal cord:

The spinal cord gets its blood supply from the following sources:-

Anterior spinal artery (ASA): 

A long single artery which supplies the anterior 2/3rd of the spinal cord. It arises from the vertebral artery (a contributing branch from both vertebral arteries) in front of the medulla. Descend along the anterior median fissure of the spinal cord.

Posterior spinal artery (PSA): 

They are two in numbers and supply the posterior 1/3rd of the spinal cord. They arise either from the vertebral artery or PICA (Posterior inferior cerebellar artery).

Blood supply to the spinal cord

Segmental arteries: 

Those arise from the surrounding arteries notably deep cervical artery, intercostal artery and lumbar artery, present at each intervertebral foramen level and reinforce the main spinal arteries (ASA and PSA). They divide and enter into the spinal cord as the anterior radicular artery and the posterior radicular artery through intervertebral foramina. Anterior radicular arteries provide blood supply along with the ASA while posterior radicular artery along with the PSA. 

Feeder artery: 

There are other feeder arteries which enter into the vertebral canal and anastomose with ASA and PSA. The great anterior medullary artery of Adamkiewicz is the major feeder artery which arises from the aorta in the lower thoracic or upper lumbar levels. It is a single artery, in most of the person, enter from the left side and serve as a major source of blood to the lower 2/3rd of the spinal cord. 

Weak points of the spinal cord in the perspective of less blood supply and prone to infarction: 
• There are such 2 points in ASA supply area; at the level of T4 and L1. 
• Similarly, in PSA supplied area, first 3 thoracic segments (T1, T2, and T3) get least blood supply and more prone to infarction. 

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