Anatomy study note · Back

Intervertebral discs

Pads of fibrocartilage between the bodies of adjacent vertebrae from C2 to the sacrum. They are the main bond between the vertebral bodies, absorb shock and let one vertebra rock on the next.

Key points

• Anulus fibrosus (outer) + nucleus pulposus (inner, semifluid).
• Present C2–sacrum; none between skull–C1 or C1–C2.
• Named by the vertebra above (L4 disc = L4/L5).
• Commonest herniations: C5/6, C6/7, L4/5, L5/S1, usually posterolateral.
• “N + 1”: L4 disc → L5 root; C5 disc → C6 root.
• L5 root: weak dorsiflexion. S1 root: weak plantar flexion, lost ankle jerk.
• IV disc: condensed middle of a sclerotome.
• Nucleus pulposus: notochord remnant.
• IV disc: fibrocartilage.
• Fibrocartilage: type I collagen, no perichondrium.

The full note in the atlas also covers

Features · Action · Nerve supply · Histology · Development · Clinical notes

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 2, PDF pp. 145–147, 179–183
• Inderbir Singh’s Human Embryology, ch. 10, PDF pp. 134–136
• BRS Cell Biology & Histology, 7th ed., ch. 7, PDF pp. 117, 120

More from the back

• Ligaments of the vertebral column
• Lumbar vertebrae
• Spinal cord
• Spinal nerves
• Suboccipital muscles
• Thoracic vertebrae
• Thoracolumbar fascia
• Vertebral column
• Atlas (C1)
• Axis (C2)
• Cervical vertebrae
• Deep muscles of the back

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