Psoas sign (abdominal x-ray)

Dr Daniel J Bell et al.

The psoas sign is a classic non-specific finding on the abdominal radiograph, potentially representing retroperitoneal pathology.

Normally on an abdominal radiograph, the lateral margins of both the psoas muscles are clearly visible due to adjacent fat. When the lateral edge of one, or both, psoas muscle(s) is no longer clearly demarcated, this is a positive psoas sign. Only a portion of the muscle edge needs to be obscured for the sign to be positive.

A psoas sign has also been described on MRI in spondylodiskitis and this is discussed separately. 

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Article information

rID: 63567
Section: Signs
Tag: cases, refs
Synonyms or Alternate Spellings:
  • Psoas sign (AXR)
  • Positive psoas sign

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Cases and figures

  • Case 1: right-sided from ruptured AAA repair
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