Glottis

The glottis is the part of the larynx consisting of the vocal folds (true vocal cords) and the opening between them (the rima glottidis). It is the narrowest portion of the adult airway and plays a critical role in phonation, airway protection, and respiration.

The glottis include:

• Vocal folds (true vocal cords): Paired mucosal folds stretched across the laryngeal lumen, containing the vocalis muscle and vocal ligament. They attach anteriorly to the thyroid cartilage and posteriorly to the arytenoid cartilages.

• Rima glottidis: The space between the vocal folds, which is the narrowest part of the laryngeal cavity in adults. Its shape changes with abduction (breathing) and adduction (phonation, Valsalva maneuver). In pediatric patients, the narrowest airway segment is the subglottis (at the cricoid ring), unlike in adults where it is the glottis itself.

• Anterior commissure: The point where the vocal folds meet anteriorly at the thyroid cartilage.

• Posterior commissure: The region between the arytenoid cartilages posteriorly.

Functional significance:

• Phonation: Vibration of the adducted vocal folds by exhaled air produces voice.

• Airway protection: Glottic closure is essential during swallowing to prevent aspiration.

• Respiration: The glottis opens widely during inspiration via abduction of the vocal folds.