The roentgenologic investigation of congenital subglottic stenosis.

Congenital subglottic stenosis, which is life-threatening to the infant, can be diagnosed by the correlation of the clinical and the roentgenologic findings. The main clinical sign is the persistence of stridor from birth. The indicative roentgenologic finding is a symmetrical narrowing of the subglottic segment which is constant in form and length during the various phases of the respiratory cycle. Two cases are presented, one confirmed by postmortem examination and the other by endoscopy. The etiology of this condition and the differential diagnosis are discussed.