Epiglottis

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The epiglottis is a flap of elastic cartilage tissue covered with a mucus membrane, attached to the root of the tongue. It projects obliquely upwards behind the tongue and the hyoid bone. The term is, like tonsils, often incorrectly used to refer to the uvula.^[1]

[edit] Anatomy and function

The epiglottis guards the entrance of the glottis, the opening between the vocal folds.^{[citation needed]}

It is normally pointed upward during breathing with its underside functioning as part of the pharynx, but during swallowing, elevation of the hyoid bone draws the larynx upward; as a result, the epiglottis folds down to a more horizontal position, with its upper side functioning as part of the pharynx. In this manner it prevents food from going into the trachea and instead directs it to the esophagus, which is more posterior.^{[citation needed]}

The epiglottis is one of nine cartilaginous structures that make up the larynx (voice box). While breathing, it lies completely within the pharynx. When swallowing it serves as part of the anterior of the larynx.^{[citation needed]}

[edit] Clinical significance

[edit] Reflexes

The glossopharyngeal nerve (CN IX) sends fibers to the upper epiglottis that contribute to the afferent limb of the gag reflex. The superior laryngeal branch of the vagus nerve (CN X) sends fibers to the lower epiglottis that contribute to the afferent limb of the cough reflex.^[2]

[edit] Infection of the epiglottis

In children, the epiglottis will occasionally become infected with Haemophilus influenzae and Streptococci in the trachea, causing massive inflammation, called "Epiglottitis". This condition has become rare in countries where vaccination against Haemophilus influenzae (Hib) is administered.^{[citation needed]}

[edit] Additional images

Larynx	Cut through the larynx of a horse	The cartilages of the larynx. Posterior view.	Ligaments of the larynx. Posterior view.
Coronal section of larynx and upper part of trachea.	The entrance to the larynx, viewed from behind.	Muscles of larynx. Posterior view.	Muscles of larynx. Side view. Right lamina of thyroid cartilage removed.
Sagittal section of nose mouth, pharynx, and larynx.	Larynx. 1=vocal cords, 2=vestibular fold, 3=epiglottis, 4=plica aryepiglottica, 5=arytenoid cartilage, 6=sinus piriformis, 7=dorsum of the tongue