Epiglottis

At a glance

English

Epiglottis

Latin (TA2)

Epiglottis

System

Respiratory

Region

Whole body

Side

Single, on the midline

About the epiglottis

The epiglottis stands at the top of the larynx, projecting upwards and backwards behind the root of the tongue and the body of the hyoid bone. Its name means above the glottis. Its outline is leaf-like, with a broad, rounded free upper part and a narrow lower stalk, the petiolus. The stalk is anchored to the back of the thyroid cartilage, just below the notch, by the thyroepiglottic ligament, and the front of the cartilage is tied to the hyoid by the hyoepiglottic ligament.

Folds of mucous membrane link it to its surroundings. In front, a median and two lateral glosso-epiglottic folds join it to the tongue and enclose a pair of small hollows, the epiglottic valleculae. At the sides, the aryepiglottic folds run back to the arytenoid cartilages and form the margins of the laryngeal inlet. The core is elastic cartilage, pitted by small holes for glands and vessels, so the flap is pliant rather than rigid. Its front surface and upper back surface carry non-keratinised stratified squamous epithelium like the back of the tongue, while the lower back surface has the ciliated respiratory lining of the airway. A few taste buds are scattered over it.

In ordinary breathing the epiglottis points upwards and air passes freely behind it into the larynx. During swallowing the larynx and hyoid are pulled up and forwards, the root of the tongue presses back, and the aryepiglottic muscles contract, so the epiglottis tips back over the inlet and food is steered into the oesophagus behind it. It is helped by closure of the vocal folds, so swallowing is still possible after the epiglottis has been removed.

Infection of the epiglottis, epiglottitis, can swell it rapidly and block the airway; it causes fever, pain on swallowing and difficult breathing and is an emergency. Vaccination against Haemophilus influenzae type b has made it uncommon. If the epiglottis and laryngeal closure fail, food or fluid may enter the airway, which can lead to aspiration pneumonia. The epiglottis and valleculae are the key landmarks when passing a breathing tube. In infants it sits high, touching the soft palate.

Function and supply

Begins at

Its stalk is attached to the back of the thyroid cartilage below the notch by the thyroepiglottic ligament.

Ends at

Its free upper part lies behind the tongue, tied to the hyoid bone by the hyoepiglottic ligament and to the tongue and arytenoids by mucous folds.

Function

Tips back over the laryngeal inlet during swallowing to help direct food and fluid into the oesophagus and away from the airway.

Nerve supply

Internal branch of the superior laryngeal nerve (vagus) for sensation; a small upper front area by the glossopharyngeal nerve.

Blood supply

Laryngeal branches of the superior thyroid artery, with twigs from the lingual artery.