infraglottic

Infraglottic is an anatomical term used to describe structures located below the glottis, the opening between the vocal folds. In humans, the infraglottic region (also called the subglottic area) lies within the larynx and extends from the inferior border of the glottis to the inferior border of the cricoid cartilage, where the airway continues into the trachea. The region’s mucosa and submucosa, along with the surrounding cartilage and connective tissue, contribute to the lower part of the larynx and the airway passage during respiration.

Boundaries and contents: Superiorly, the boundary is the inferior margin of the vocal folds; inferiorly, the cricoid cartilage’s lower border marks the transition to the trachea. The conus elasticus helps form part of the lower boundary, and the infraglottic space is lined by respiratory mucosa continuous with the trachea. This region contains intrinsic laryngeal structures near the glottis and serves as the initial segment of the lower airway.

Clinical significance: Changes in the infraglottic region, such as subglottic edema, stenosis, or tumors, can cause airway obstruction and breathing difficulties. It is a focus during airway management and endoscopy, including laryngoscopy and imaging, to evaluate conditions affecting voice, breathing, or airway patency. Subglottic pathology is particularly relevant in pediatric cases, where subglottic stenosis or edema can present with stridor and respiratory distress.

See also: subglottis, glottis, larynx, trachea.