Syndesmophyte

Last revised by Dr Mohammad Taghi Niknejad on 17 Aug 2021

Syndesmophytes are calcifications or heterotopic ossifications inside a spinal ligament or of the annulus fibrosus.​ They are seen in only a limited number of conditions including: 

They can be classified as marginal (along the margins of the vertebral bodies) or non-marginal (larger and bulky away from the vertebral bodies). Ankylosing spondylitis classically displays symmetrical marginal syndesmophytes.

Appearance on plain radiographs comprises vertical and symmetrical calcification of the lateral margins of the intervertebral disc space

  • osteophyte: ossification at synovial margins, typically protruding perpendicular to the spine cf. syndesmophytes that run parallel with the spine
  • enthesophyte: located at an attachment of a ligament or tendon, not associated with a joint

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Cases and figures

  • Figure 1: syndesmophyte v osteophyte (illustration)
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  • Case 1: ochronosis
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  • Case 2: ankylosing spondylitis
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  • Case 3: fluorosis
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  • Case 4: ankylosing spondylitis
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