Nils Westermark

Nils Johan Hugo Westermark (1892 - 1980)

Nils Johan Hugo Westermark (1892 – 1980) was a Swedish radiologist.

He is eponymously affiliated with the Westermark sign (1938) of relative oligemia on chest x-ray in pulmonary embolism.

Westermark was an Olympic silver medalist for sailing in the 1912 Stockholm Games.

  • Born 9 September 1892 in Stockholm, Sweden
  • 1912 – Represented Sweden (silver medal) at the Fifth Olympic Games in Stockholm, sailing in the 8 metre class on Sans Atout (boat)
  • 1919 – Graduated with MD degree from Karolinska Institutet Medical School, Sweden
  • 1920-29 – Radiologist at Sabbatsbergs Hospital (1920-21); Karolinska Radium Hospital (1922-23); and St Eriks Hospital (1923-29)
  • 1928-57 – Board member on the Swedish Society of Medical Radiology
  • 1928-53 – Member of the Nordic Society of Medical Radiology
  • 1930-57 – St. Göran’s Hospital
  • 1930 – Awarded PhD in medicine (radiology)
  • 1930 – Appointed Dozent (associate professor) at Karolinska Institutet
  • 1930-57 – Radiologist at Saint Göran Hospital, Stockholm
  • 1955 – Professor of radiology at Karolinska Institutet
  • 1946 – Presented first Rigler lecture at the University of Minnesota
  • Died 24 January 1980 in Stockholm, Sweden

Medical Eponyms
Westermark sign (1938)

Westermark sign describes chest x-ray findings in pulmonary embolism of a clarified area distal to a large vessel that is occluded by an embolus. The focal area of increased translucency (oligaemia), occurs due to impaired vascularisation of the lung from primary mechanical obstruction or reflex vasoconstriction.

Westermark identified these chest radiograph features after examining 28 cases of autopsy proven pulmonary embolism, and published his findings in a 1938 paper.

This sign has been described to have 14% sensitivity; 92% specificity; 38% PPV; and 76% NPV (PIOPED 1993).

Major Publications



the names behind the name

Doctor in Australia. Keen interest in internal medicine, medical education, and medical history.

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