Anterior radicular artery
Arteria radicularis anterioris
- Eponym: Adamkiewicz
Definition
The anterior radicular artery is a blood vessel that accompanies the ventral (anterior) nerve roots as they enter the spinal canal through the intervertebral foramina. These arteries arise from segmental vessels including the vertebral, ascending cervical, deep cervical, intercostal, lumbar, and sacral arteries and travel along the anterior nerve roots to reach the anterior spinal artery, reinforcing its blood supply to the spinal cord.
Key anatomical and clinical features:
Course: Each anterior radicular artery enters the intervertebral foramen alongside the spinal nerve root, courses medially along the ventral root, and anastomoses with the anterior spinal artery on the ventral surface of the spinal cord.
Distribution: Not every spinal segment has a functionally significant anterior radicular artery. While small radicular branches exist at most levels, only a limited number (typically 68) are large enough to meaningfully contribute to the anterior spinal artery's flow.
Artery of Adamkiewicz: The largest and most clinically important anterior radicular artery is the artery of Adamkiewicz (arteria radicularis magna), which most commonly arises on the left side between T9 and T12 (though it can originate anywhere from T8 to L2). It is the dominant blood supply to the lower two-thirds of the spinal cord.
Clinical significance: The anterior radicular arteries are critical for maintaining spinal cord perfusion. Disruption of these vessels particularly the artery of Adamkiewicz during thoracoabdominal aortic surgery, spinal surgery, or due to aortic pathology (e.g., dissection) can result in anterior spinal artery syndrome, characterized by motor paralysis, loss of pain and temperature sensation, and autonomic dysfunction below the level of ischemia, with preservation of proprioception and vibration (posterior column sparing).
Watershed zones: The mid-thoracic spinal cord (approximately T4-T8) is a recognized watershed zone between the upper and lower radicular arterial territories, making it particularly vulnerable to ischemic injury.
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