Disc herniation

Dr Henry Knipe and A.Prof Frank Gaillard et al.

Disc herniation refers to the displacement of intervertebral disc material beyond the normal confines of the disc but involving less than 25% of the circumference (to distinguish it from a disc bulge. A herniation may contain nucleus pulposus, vertebral endplate cartilage, apophyseal bone/osteophyte and annulus fibrosus

Disc herniations can be divided into groups in a variety of ways. Commonly they are divided into protrusion vs extrusion: 

  • protrusion
    • base wider than herniation
    • confined to disc level
    • outer annular fibres intact
  • extrusion
    • base (a.k.a. neck) narrower than herniation 'dome'
    • may extend above or below endplates or adjacent vertebrae
    • complete annular tear with passage of nuclear material beyond disc annulus
    • disc material can then migrate away from annulus or become sequestered

Herniations can further be classified as:

  • contained
  • not contained
    • tear of outer fibres of annulus fibrosus and posterior longitudinal ligament

See also

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Article information

rID: 6191
Synonyms or Alternate Spellings:
  • Disc herniations
  • Disk herniation
  • Disk herniations

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Cases and figures

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    Figure 1: normal
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    A focal disc prot...
    Figure 2: disc extrusion
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    Figure 3: disc protrusion
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    Figure 4: disc extrusion
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    Figure 5: disc sequestration
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    Figure 6: lumbar disc herniation
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