The spinal cord receives its blood supply from a combination of the anterior spinal artery and the posterior spinal arteries.
The spinal cord's blood supply is crucial for its function and integrity. Compromise of this vascular network can lead to significant neurological deficits. The blood supply comes from longitudinal arteries that run the length of the cord, supplemented by radicular arteries that enter at various levels.
Arterial Supply Details:
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Anterior Spinal Artery (ASA):
- This single artery supplies approximately the anterior two-thirds of the spinal cord.
- It's formed by branches from the vertebral arteries near the foramen magnum.
- The ASA descends along the anterior median fissure of the spinal cord.
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Posterior Spinal Arteries (PSAs):
- There are two posterior spinal arteries, supplying the posterior one-third of the spinal cord.
- These arteries arise either directly from the vertebral arteries or from the posterior inferior cerebellar arteries (PICA).
- The PSAs course along the posterolateral aspect of the spinal cord, near the dorsal nerve roots.
Segmental Reinforcement:
While the ASA and PSAs run longitudinally, they are relatively small and require segmental reinforcement from radicular arteries. These radicular arteries originate from various sources, including:
- Vertebral arteries
- Ascending cervical arteries
- Intercostal arteries
- Lumbar arteries
- Sacral arteries
These arteries enter the vertebral canal through the intervertebral foramina and supply both the spinal cord and the nerve roots. The largest of these radicular arteries is the artery of Adamkiewicz (arteria radicularis magna), typically arising on the left side between T9 and L2. This artery provides significant blood supply to the lower thoracic and lumbar regions of the spinal cord.
Venous Drainage:
The venous drainage of the spinal cord generally parallels the arterial supply. Blood drains into a network of veins that eventually empty into the internal vertebral venous plexus, which then drains into systemic veins.
Clinical Significance:
Interruptions in the spinal cord's blood supply can lead to spinal cord infarction, causing various neurological deficits depending on the location and extent of the ischemia. The anterior spinal artery is particularly vulnerable, and occlusion can result in anterior spinal artery syndrome, characterized by loss of motor function, pain and temperature sensation (below the level of the lesion), while preserving proprioception and vibration sense.
