L4 — fourth lumbar vertebra (Vertebra lumbalis quarta)
Educational content only — not medical advice.
Anatomy
L4, the fourth of five massive lumbar vertebrae carrying the trunk's weight: a broad kidney-shaped body, a hatchet-shaped horizontal spinous process and slender transverse processes. Its sagittally oriented facet joints lock rotation in favour of low-back stability.
Clinical notes
Lumbar disc herniation at L4 may compress the L5 root, producing classic sciatica with pain below the knee.
Related structures
Educational references
FAQ
What is the role of the L4 — fourth lumbar vertebra?
L4, the fourth of five massive lumbar vertebrae carrying the trunk's weight: a broad kidney-shaped body, a hatchet-shaped horizontal spinous process and slender transverse processes. Its sagittally oriented facet joints lock rotation in favour of low-back stability.
Why is the L4 — fourth lumbar vertebra clinically important?
Lumbar disc herniation at L4 may compress the L5 root, producing classic sciatica with pain below the knee.
Source & license
Derived from Z-Anatomy (Gauthier Kervyn et al.), CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/); upstream geometry from BodyParts3D, © The Database Center for Life Science. license details