Radicular arteries are small blood vessels that supply blood to the spinal cord and its associated nerve roots. These vessels are found along the spine, entering the vertebral column at various levels. They form a network supporting the neural structures within the spinal canal.
Anatomy and Purpose of Radicular Arteries
Radicular arteries originate from larger segmental arteries, such as intercostal, lumbar, vertebral, or cervical arteries. After branching, they travel inward, following spinal nerve roots into the vertebral column through the intervertebral foramina. Inside, they divide into anterior and posterior branches, accompanying the spinal nerve roots.
Radicular arteries deliver oxygenated blood and nutrients to the spinal cord and nerve roots. While anterior and posterior spinal arteries form the main longitudinal blood supply, radicular arteries act as “feeder” or “booster” vessels, reinforcing this supply. Their number and distribution vary significantly among individuals, contributing to a complex, sometimes discontinuous arterial network along the spinal cord.
The Artery of Adamkiewicz: A Specialized Vessel
Among radicular arteries, the Artery of Adamkiewicz, also known as the Great Anterior Radiculomedullary Artery or Arteria Radicularis Magna, is particularly important. This single, large vessel provides substantial blood supply to the anterior spinal artery, especially for the lower two-thirds of the spinal cord, including the lumbar enlargement and conus medullaris. It most commonly originates from a posterior intercostal or lumbar artery, usually between T8 and L1 vertebral levels, with a notable 77-80% prevalence on the left side.
The Artery of Adamkiewicz often enters the spinal canal at the T9 to T11 vertebral level, though its origin can range from T3 to L4. It then makes a characteristic “hairpin” turn as it joins the anterior spinal artery on the surface of the spinal cord. This unique arrangement makes it a dominant supplier to a large spinal cord segment, and its singular nature means compromise can have widespread neurological implications. Its diameter is 0.8 to 1.3 mm.
Clinical Relevance
Radicular arteries, especially the Artery of Adamkiewicz, are important for maintaining spinal cord perfusion. Disruption to their blood flow can lead to serious neurological consequences. Spinal cord ischemia or infarction occurs when these arteries are damaged, blocked, or compromised, resulting in insufficient oxygen and nutrient delivery to spinal cord tissue. Symptoms can include sudden back pain, weakness, numbness, or difficulty controlling leg and arm muscles, varying based on the affected spinal cord segment.
Surgical procedures, particularly those involving the aorta (such as aortic aneurysm repair) or extensive spinal surgeries (like scoliosis correction or tumor removal), risk inadvertently injuring radicular arteries. Surgeons prioritize identifying and preserving these vessels during operations to prevent iatrogenic spinal cord injury. The Artery of Adamkiewicz’s highly variable location (T3 to L4) adds complexity to surgical planning, underscoring the need for careful preoperative assessment.
Diagnostic imaging visualizes these arteries for clinical purposes. Techniques like computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) map the spinal vasculature, aiding diagnosis, surgical planning, and evaluation of suspected vascular anomalies. This helps medical professionals understand each patient’s unique arterial supply.
Radicular arteries are also involved in conditions such as spinal arteriovenous malformations (AVMs). These are abnormal tangles where arteries connect directly to veins without a capillary network. Spinal dural arteriovenous fistulas (SDAVFs), a common type, involve an abnormal connection between a dural branch of a radicular artery and a radicular vein, often leading to venous congestion and neurological symptoms.