X Ray findings in croup patients include evidence of steeple sign: narrowing of the subglottic lumen in the neck. It also includes a visibly distended hypopharynx in some cases.

• Steeple sign is seen on anteroposterior radiographs of the soft tissues of the neck.^[1]

• Normal lateral convexities of the subglottic trachea are lost, and narrowing of the subglottic lumen produces an inverted V configuration in this area.
• The point of the inverted V is at the level of the inferior margin of the true vocal cords.
• Narrowing of the subglottic lumen alters the radiographic appearance of the tracheal air column, which resembles a steeply pitched roof or a church steeple.

• The lateral radiograph of the upper airway will show a normal epiglottis and narrowing of the subglottic region.^[1]
• Distension of the hypopharynx can is also be revealed by x ray, indicating a patient’s attempt at decreasing airway resistance.

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  Frontal view of the steeple sign in a croup patient. From Radiopaedia Image Library. ^[2]
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  Frontal view of the steeple sign in a croup patient. From Radiopaedia Image Library. ^[2]
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  Lateral view of the steeple sign in a croup patient. From Radiopaedia Image Library. ^[2]
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  Lateral view of the steeple sign in a croup patient that also displays distended hypopharynx. From Radiopaedia Image Library. ^[2]