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What is Thumb sign in lateral X- ray of neck seen in - and explain in detail?
In epiglottis: A plain lateral soft tissue radiograph of neck shows the following specific features:
Thickening of the epiglottis—the thumb sign
Absence of a deep well-defined vallecula—the vallecula sign.
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Steeple sign i.e. narrowing of subglottic region is seen in chest X-ray of patients of laryngotracheobronchitis (i.e. croup).