Thoracoabdominal sign

Thoracoabdominal sign, a variation of the silhouette sign, is a frontal chest radiograph sign which helps to localize a thoracic lesion.

Since the posterior costophrenic sulcus is more caudal than the anterior lung, a thoracic lesion must be posterior if its caudal end is visible below the dome of diaphragm.

History and etymology

Dr. Benjamin Felson (1913-1988) was an American radiologist who first described this sign.


Chest x-ray
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Article Information

rID: 27152
System: Chest
Section: Signs
Tags: cases, refs
Synonyms or Alternate Spellings:
  • Thoraco abdominal sign
  • Abdomino thoracic sign
  • Thoraco-abdominal sign

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