Fourth lumbar vertebra at a glance
- Also called
- L4
- What it is
- The fourth of the five lumbar vertebrae, labelled L4, in the lower back.
- Location
- Lies in the lower lumbar spine between L3 and L5.
- Function
- Bears the weight of the upper body and allows flexion and extension of the lower back.
- Body system
- Skeletal · single, midline structure
- FMA ID
- FMA13075 (Foundational Model of Anatomy)
Key facts
- A line joining the highest points of the iliac crests (supracristal plane) crosses the L4 spinous process or the L4-L5 interspace, and is used to locate lumbar puncture sites.
- The aorta divides into the common iliac arteries at about L4.
- The umbilicus usually lies at about the L3–L4 disc level in a healthy adult.
Clinical relevance
The L4-L5 and L5-S1 discs are the most common sites of lumbar disc herniation.
Structures next to the fourth lumbar vertebra
The nearest named structures in the 3D model, measured from the centre of each part:
- Intervertebral disk of fourth lumbar vertebra · skeletal
- Intervertebral disk of third lumbar vertebra · skeletal
- Third lumbar vertebra · skeletal
- Fifth lumbar vertebra · skeletal
- Interspinales lumborum · muscular
- Lumbar vein · cardiovascular
- Lumbar artery · cardiovascular
- Common iliac vein · cardiovascular
- Taenia mesocolica · digestive
- Transverse mesocolon · digestive
References
- Foundational Model of Anatomy: Fourth lumbar vertebra (FMA13075). EMBL-EBI Ontology Lookup Service.
- OpenStax. Anatomy and Physiology 2e, §7.1 Divisions of the Skeletal System. Rice University, 2022.
- Mitsuhashi N. et al. (2009). BodyParts3D: 3D structure database for anatomical concepts. Nucleic Acids Research 37, D782–D785. Data © The Database Center for Life Science, CC BY 4.0.
Related anatomy
Explore the whole body in the interactive 3D human anatomy model, or browse the A–Z list of human structures.