In chest radiography, the<unk> , is a sign that represents a focus of oligemia (vasoconstriction) seen distal to a pulmonary embolus (PE). While the chest x-ray is abnormal in the majority of PE cases, the<unk>  is seen in only 2% of patients.
The sign results from a combination of:
Westermark sign
Lighthouse sign
Lincoln sign
Sherman sign
Quincke sign
McConnell sign
Steeple sign
Fleischner sign