What does the "thumb sign" on an x-ray indicate?

The "thumb sign" on an x-ray is indicative of supraglottic swelling, particularly associated with conditions such as epiglottitis. This term describes a specific appearance of the swollen epiglottis that resembles a thumb positioned upright. In the context of epiglottitis, the inflammation and swelling can obstruct the airway, making it a critical finding during the assessment of a patient presenting with respiratory distress or stridor. The detection of this sign can help guide the urgency of medical intervention, emphasizing the need for close monitoring and possible airway management in a clinical setting. Understanding this radiographic feature is essential for recognizing airway emergencies and initiating appropriate care promptly.