Subglottic (endolaryngeal) injury can cause a subglottic stenosis. Chronic subglottic stenosis is defined as a partial narrowing (to complete obliteration) of the airway bounded by the inferior margin of the cricoid at the caudal side and cranially by the insertion of the fibres of the conus elasticus into the true vocal cords. Subglottic stenosis may be congenital or acquired. A congenital subglottic stenosis is the remnant of an incomplete recanalization of the laryngeal lumen after completion of normal epithelial fusion at the end of the third month of gestation. Mostly, a stenosis at the level of the subglottis is acquired and considered to be the consequence and thus the complication of an extra- or endolaryngeal injury to the larynx. An external trauma causes fractures of the cartilaginous skeleton with lacerations of the soft tissues. An acquired subglottic stenosis following prolonged endotracheal intubation develops in 0.9 - 8.5 % of prematurely born neonates who need artificial respiration, is often more severe and now forms the largest proportion of cases in infants and children.