Lumbar Arteries: Anatomy, Origin, Course, Branches, Relations, Function, Clinical Significance, MRI & CT Imaging

Topic

Lumbar arteries

The lumbar arteries are a set of four paired segmental arteries that arise from the posterior wall of the abdominal aorta. They supply the posterior abdominal wall, spinal cord, vertebrae, and associated musculature. A fifth pair sometimes arises from the median sacral artery. Each artery runs laterally and posteriorly across the lumbar region, giving off branches to muscles, skin, spinal cord, and vertebrae.

They form important anastomoses with the intercostal, iliolumbar, and inferior epigastric arteries, creating collateral circulation pathways. Because of their spinal branches, they are clinically significant in spinal cord perfusion and risk of ischemia during aortic surgery.

Synonyms

Posterior abdominal wall segmental arteries
Dorsal lumbar arteries
Abdominal segmental arteries

Origin, Course, and Branches

Origin:
- Four pairs usually arise from the posterior aspect of the abdominal aorta, opposite the L1–L4 vertebrae
- Occasionally a fifth pair arises from the median sacral artery
Course:
- Each artery runs laterally across the vertebral bodies, posterior to the sympathetic trunk and inferior vena cava (on the right side)
- They pass behind the psoas major muscle and anterior to the lumbar plexus
- Course continues laterally between the transversus abdominis and internal oblique muscles
Branches:
- Dorsal branches: supply spinal cord, vertebral column, meninges, and muscles of the back
- Muscular branches: supply psoas, quadratus lumborum, abdominal wall muscles
- Cutaneous branches: supply skin of lumbar region
- Spinal branches: enter intervertebral foramina to supply spinal cord and meninges

Relations

Anteriorly: Sympathetic trunk, inferior vena cava (on right side), peritoneum
Posteriorly: Vertebral bodies, psoas major, lumbar vertebrae
Laterally: Quadratus lumborum, lumbar plexus branches
Medially: Abdominal aorta

Function

Supply the posterior abdominal wall muscles (psoas, quadratus lumborum, transversus abdominis, internal oblique)
Supply the spinal cord, cauda equina, and meninges via spinal branches
Supply the vertebrae and periosteum of lumbar spine
Contribute to collateral circulation with intercostal, iliolumbar, inferior epigastric, and median sacral arteries

Clinical Significance

Important in collateral circulation during aortic occlusion or surgery
Source of bleeding in retroperitoneal hemorrhage or trauma
Vulnerable during aortic aneurysm repair or spinal surgery (risk of spinal cord ischemia)
Hypertrophied lumbar arteries may be seen in arteriovenous malformations or tumors
Their spinal branches contribute to the artery of Adamkiewicz, critical for spinal cord perfusion

MRI Appearance

T1-weighted images:

Arteries appear as flow voids (dark signal) due to rapid blood flow
Surrounding retroperitoneal fat appears bright, outlining their course

T2-weighted images:

Arteries remain as flow voids (dark signal)
Slow or turbulent flow may produce mild hyperintense signal

STIR (Short Tau Inversion Recovery):

Arteries remain dark flow voids
Adjacent fat is suppressed, improving visualization of vessel lumen and pathology

T1 Fat-Sat Post-Contrast:

Arteries enhance brightly and uniformly with contrast, clearly delineating their lumen
Useful for evaluating stenosis, aneurysm, or collateral circulation

CT Appearance

Non-Contrast CT:

Arteries appear as small tubular soft tissue densities along the posterior abdominal wall
Surrounded by retroperitoneal fat, which provides contrast
Calcifications may be seen in atherosclerosis

Post-Contrast CT (CT Angiography):

Arteries enhance brightly
Branching pattern and spinal contributions can be visualized
Allows detection of stenosis, aneurysms, traumatic injury, or hypertrophied collaterals

MRI image

CT image

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