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Radiographic features of pulmonary embolism: Westermark and Palla signs
  1. Ausami Abbas1,
  2. Emma V St Joseph2,
  3. Osama M A Mansour3,
  4. Charles R Peebles1
  1. 1Department of Radiology, Southampton University Hospitals NHS Foundation Trust, Southampton, UK
  2. 2Department of Respiratory Medicine, The Royal Surrey County Hospital NHS Foundation Trust, Guildford, UK
  3. 3Southampton University School of Medicine, Southampton, UK
  1. Correspondence to Dr Ausami Abbas, Block C, Radiology Department, Southampton University Hospitals NHS Foundation Trust, Tremona Road, Southampton, Hampshire SO16 6YD, UK; drausami_abbas{at}

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Classic chest radiograph signs of pulmonary emboli include regional oligaemia (‘Westermark sign’), right descending pulmonary artery enlargement (‘Palla sign’), central pulmonary artery enlargement (‘Fleishner sign’) and abrupt pulmonary artery tapering (‘knuckle sign’).1 We present a case highlighting the importance of recognising these unusual radiological signs in patients presenting with haemodynamically unstable pulmonary emboli (box 1).

Box 1

CXR appearance of Westermark and Palla signs

Westermark sign: regional pulmonary oligaemia

Palla sign: enlargement of the descending pulmonary artery


A 78-year-old lady presented to the emergency department with collapse and pleuritic chest pain. On examination, the patient was in respiratory distress and haemodynamic …

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  • Contributors All authors were involved in patient care, manuscript development and literature review.

  • Competing interests None.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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