Intervertebral disk of first lumbar vertebra: anatomy, location and function

What it is

The intervertebral disc between L1 and L2 (the L1–L2 disc), a fibrocartilage pad with a gel-like nucleus pulposus inside a ring-like anulus fibrosus.

Location

Between the bodies of L1 and L2, the disc directly below the named vertebra (the L1/L2 disc).

Function

Absorbs compressive loads, acts as a shock absorber and allows slight movement between vertebrae.

Body system

Skeletal · single, midline structure

FMA ID

FMA16033 (Foundational Model of Anatomy)

Key facts

• It lies at about the level of the conus medullaris, where the adult spinal cord ends, so a large herniation here can compress the conus or the cauda equina.
• Lumbar discs are the thickest in the column and, like the cervical discs, are taller anteriorly, producing the lumbar lordosis.

Clinical relevance

Herniation is uncommon at this level; a posterolateral herniation usually compresses the L2 root (groin and upper thigh pain, weak hip flexion).

The nearest named structures in the 3D model, measured from the centre of each part:

• Abdominal aorta · cardiovascular
• First lumbar vertebra · skeletal
• Renal artery · cardiovascular
• Pancreatic duct · digestive
• Pancreas · digestive
• Second lumbar vertebra · skeletal
• Renal vein · cardiovascular
• Intervertebral disk of second lumbar vertebra · skeletal
• Posterior division of renal artery · cardiovascular
• Posterior superior pancreaticoduodenal artery · cardiovascular