Epiglottis

The epiglottis is a leaf-shaped piece of elastic cartilage covered by mucous membrane that sits behind the root of the tongue and in front of the laryngeal inlet. It plays a key role in swallowing by acting as a switch between the airway and the esophagus: during swallowing it folds down to cover the opening of the larynx, helping prevent aspiration; during breathing it remains upright to allow air to pass into the airway.

Anatomically, the epiglottis is attached to the thyroid cartilage by the thyroepiglottic ligament and to the hyoid bone by the hyoepiglottic ligament. It has an upper lingual surface that faces the tongue and a lower laryngeal surface that faces the glottis. The mucosa is typically stratified squamous on the lingual side and pseudostratified ciliated epithelium on the laryngeal side. It consists of elastic cartilage, which provides flexibility for movement during swallowing.

Blood supply is derived from branches of the superior thyroid and inferior laryngeal arteries, with venous drainage to the corresponding veins. Sensory innervation of the epiglottic mucosa is mainly via the internal branch of the superior laryngeal nerve (a branch of the vagus). Motor control of the laryngeal entrance is mediated by nerves of the vagus, notably the recurrent laryngeal nerve, and coordinated by tongue and pharyngeal muscles during swallowing.

Clinical relevance includes epiglottitis, a potentially life-threatening inflammation that can cause rapid airway obstruction, especially in children. It is a medical emergency requiring prompt airway management. Vaccination has reduced incidence related to Haemophilus influenzae type b; other pathogens and noninfectious causes can also affect the epiglottis.