Os triangulare

Dr Yuranga Weerakkody and Dr Henry Knipe et al.

The os triangulare (also known as the os intermedium antebrachii or os triquetrum secundarium) is an accessory ossicle located between the ulnar styloid, lunate and triquetrum 1,2.

They may be unilatreal or bilateral and the main differential diagnosis is non-union of an ulnar styloid process fracture 1,3.

Differential diagnosis

Anatomy: Upper limb
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Article information

rID: 25056
Section: Anatomy
Synonyms or Alternate Spellings:
  • Os triquetrum secundarium
  • Os triangulare
  • Os intermedium antebrachii

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Cases and figures

  • Os triangulare
    Figure 1: os triangulare (annotated image)
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  • Case 1
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  • Case 2
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  • Case 3
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  • Case 4
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