Epiglottis

Epiglottis
Laryngoscopic view of interior of larynx
Gray's	subject #236 1095
Precursor	4th and 6th branchial arch[1]

The epiglottis is a lid-like 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.

Anatomy and function

The epiglottis guards the entrance of the glottis, the opening between the vocal folds.

It is normally pointed upward, but during swallowing, elevation of the hyoid bone draws the larynx upward; as a result, the epiglottis folds down to a more horizontal position. In this manner it prevents food from going into the trachea and instead directs it to the esophagus, which is more posterior.

The epiglottis is one of three large cartilaginous structures that make up the larynx (voice box).

Clinical significance

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]

Infection of the epiglottis

In children, the epiglottis will occasionally become infected with Haemophilus influenzae or Streptococcus pneumoniae bacteria. Although easily treated, this condition is a medical emergency because without treatment the epiglottis may swell and block the trachea, causing massive inflammation. This condition has become rare in countries where vaccination against Haemophilus influenzae (HIB) is administered.

Additional images

Larynx	Cut through the larynx of a horse	The cartilages 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.
Sagittal section of nose mouth, pharynx, and larynx.

Ligaments of the larynx. Posterior view.

Muscles of larynx. Side view. Right lamina of thyroid cartilage removed.

References

1. ^ Embryology at UNC hednk-025d
2. ^ April, Ernest. Clinical Anatomy, 3rd ed. Lippincott, Williams, and Wilkins.

External links

• Norman/Georgetown lesson11 (larynxsagsect)

General anatomy of neck (Throat • Pharynx • Larynx)
Cartilages	Cricoid • Thyroid (Adam's apple) • Epiglottis • Arytenoid • Cuneiform • Corniculate
Ligaments	extrinsic ligaments: Thyrohyoid membrane (Lateral thyrohyoid ligament, Median thyrohyoid ligament) • Hyoepiglottic ligament • Cricotracheal ligament intrinsic ligaments: Cricothyroid ligament
Folds and related structures	folds: (Glossoepiglottic, Aryepiglottic, Vocal, Vestibular) Vocal ligament • Ventricle of the larynx • Infraglottic cavity • Vestibule of larynx • Rima glottidis • Glottis
Triangles of the neck	Anterior of the neck (Muscular, Carotid, Submandibular, Submental) Posterior of the neck (Occipital, Subclavian) Suboccipital
Fascia	Deep cervical fascia (Pretrachial fascia, Prevertebral fascia, Investing layer) • Carotid sheath
Other	Retropharyngeal space