Great radicular artery
Arteria radicularis magna
- Latin synonym: Arteria medullaris segmentalis magna
- Synonym: Great segmental medullary artery
- Eponym: Artery of Adamkiewicz
- Related terms: Anterior segmental medullary artery; Anterior segmental medullary artery (Adamkiewicz)
Definition
The great radicular artery (Artery of Adamkiewicz; AKA; Arteria radicularis magna, is the largest radiculomedullary artery and the most important branch vessel feeding the anterior spinal artery. It serves as the principal blood supply to the lower two-thirds of the spinal cord, including the lower thoracic and lumbar segments.
Anatomical characteristics:
Origin: It arises from a segmental artery (intercostal or lumbar artery) branching off the thoracoabdominal aorta, most commonly between T9 and T12, though it can originate anywhere from T5 to L2.
Laterality: In approximately 80-85% of individuals, it arises from the left side of the aorta.
Course: It enters the spinal canal through an intervertebral foramen, accompanying a ventral nerve root, and forms a characteristic "hairpin turn" as it reaches and joins the anterior spinal artery, coursing caudally to supply the lower spinal cord.
Multiplicity: Most individuals (approximately 74%) have a single artery of Adamkiewicz, though about 26% may have two or even three.
Clinical significance:
The great radicular artery is of paramount importance in thoracic and thoracoabdominal aortic surgery, spinal surgery, and endovascular procedures. Interruption of this artery whether during open aortic repair, thoracic endovascular aortic repair (TEVAR), tumor embolization, or spinal instrumentation can result in anterior spinal cord ischemia and paraplegia. The thoracic spinal cord between T4 and T9 represents a watershed zone with relatively tenuous blood supply, making it particularly vulnerable when the artery of Adamkiewicz is compromised. Preoperative identification using high-resolution CT angiography is recommended to guide surgical planning and reduce the risk of spinal cord injury.
It is also worth noting that a great posterior radiculomedullary artery has been described, present in approximately 72% of individuals, with an average diameter of 0.44 mm, supplying the posterior spinal arteries. This vessel is distinct from the artery of Adamkiewicz, which supplies the anterior spinal artery.
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