Arteriae lumbales imae

The Arteriae lumbales imae (lowest lumbar arteries) are a pair of small arteries that arise from the median sacral artery (or occasionally from the aortic bifurcation or common iliac arteries). They represent the fifth pair of lumbar arteries and supply the lower lumbar vertebrae, the sacrum, and surrounding musculature.

Anatomical Details

• Origin: The arteriae lumbales imae typically originate from the median sacral artery (arteria sacralis mediana), which itself arises from the posterior aspect of the aorta just above its bifurcation. In some anatomical variants, they may arise directly from the aortic bifurcation or the common iliac arteries.

• Course: They course laterally across the body of the fifth lumbar vertebra (L5), following a similar trajectory to the other lumbar arteries (L1-L4), which arise directly from the abdominal aorta.

• Branches: Like the other lumbar arteries, they give off:

  • Dorsal branches supplying the muscles and skin of the lower back

  • Spinal branches entering the vertebral canal through the intervertebral foramina to supply the spinal cord, cauda equina, and meninges

• Supply territory: The lumbosacral region, including the L5 vertebral body, adjacent intervertebral disc, paraspinal muscles, and contributions to the spinal canal vasculature.