Intervertebral Disk of Fifth Lumbar Vertebra (L5–S1) (Discus intervertebralis L5–S1)
Educational content only — not medical advice.
Anatomy
The intervertebral disk of the fifth lumbar vertebra (L5–S1), or lumbosacral disk, connects the mobile lumbar spine to the rigid sacrum at the sacrovertebral angle (promontory). Markedly wedge-shaped with a tall anterior profile, it withstands the highest shear stresses and compressive loads in the entire human skeleton.
Clinical notes
The L5–S1 disk is the second most common site of lumbar herniation; compression of the S1 nerve root causes sciatica radiating down the posterior calf to the lateral foot, gastrocnemius weakness (inability to walk on toes), and loss of the Achilles tendon reflex.
Related structures
Educational references
FAQ
What is the role of the Intervertebral Disk of Fifth Lumbar Vertebra (L5–S1)?
The intervertebral disk of the fifth lumbar vertebra (L5–S1), or lumbosacral disk, connects the mobile lumbar spine to the rigid sacrum at the sacrovertebral angle (promontory). Markedly wedge-shaped with a tall anterior profile, it withstands the highest shear stresses and compressive loads in the entire human skeleton.
Why is the Intervertebral Disk of Fifth Lumbar Vertebra (L5–S1) clinically important?
The L5–S1 disk is the second most common site of lumbar herniation; compression of the S1 nerve root causes sciatica radiating down the posterior calf to the lateral foot, gastrocnemius weakness (inability to walk on toes), and loss of the Achilles tendon reflex.
Source & license
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