Lumbar vertebra L3

Function

Mid-lumbar workhorse; its segment supplies knee extension (via the femoral nerve from L2–4) and sensation above the knee.

Landmarks

• Body
• Transverse processes
• Articular facets
• Spinous process

Articulations (joints)

• L2 above
• L4 below

Clinical relevance

The femoral nerve stretch test aggravates L2–4 radiculopathy; the L3–4 disc level presses the L4 root, dulling the knee-jerk reflex.