[Rare acute disease pictures of the upper respiratory tract in children].

The radiologist should recognize dangerous uncommon conditions such as epiglottitis and membranous croup by their pattern on conventional images. Subglottic narrowing, as from croup, is recognizable on lateral images by loss of the superior interface of trachea and vocal cords. A lateral image is important when an upper esophageal foreign body is seen on a frontal view.