Human pharynx

Human pharynx
Head and neck.
Pharynx
Gray's	subject #244 1141
Artery	pharyngeal branches of ascending pharyngeal artery, ascending palatine, descending palatine, pharyngeal branches of inferior thyroid
Vein	pharyngeal veins
Nerve	pharyngeal plexus
MeSH	Pharynx

The pharynx (plural: pharynges) is the part of the neck and throat situated immediately posterior to (behind) the mouth and nasal cavity, and cranial, or superior, to the esophagus, larynx, and trachea.

Functions

The pharynx is part of the digestive system and respiratory system of many organisms.

Because both food and air pass through the pharynx, a flap of connective tissue called the epiglottis closes over the trachea when food is swallowed to prevent choking or aspiration. In humans the pharynx is important in vocalization.

Parts

The human pharynx is conventionally divided into three sections:

Nasopharynx

The nasopharynx region extends between the internal nares and the soft palate and lies superior to the oral cavity. Some lymphoid tissue—the pharyngeal tonsils or the adenoids—are located in the posterior wall. The Eustachian tubes, or auditory tubes, which connect the middle ear to the pharynx, open into the nasopharynx. The opening opens and closes, equalizing the air pressure in the middle ear to that of the atmosphere. This is needed for proper conduction of sound.

Oropharynx

The oropharynx lies behind the oral cavity. The anterior wall consists of the base of the tongue and the epiglottic vallecula; the lateral wall is made up of the tonsil, tonsillar fossa, and tonsillar (faucial) pillars; the superior wall consists of the inferior surface of the soft palate and the uvula.

Laryngopharynx

The laryngopharynx, also known as the hypopharynx, roughly corresponds to the levels between C4 to C6, it includes the pharyngo-esophageal junction (postcricoid area), the piriform sinus, and the posterior pharyngeal wall.

Like the oropharynx above it, the hypopharynx serves as a passageway for food and air and is lined with a stratified squamous epithelium.

It lies inferior to the upright epiglottis and extends to the larynx, where the respiratory and digestive pathways diverge.

At that point, the laryngopharynx is continuous with the esophagus posteriorly. The esophagus conducts food and fluids to the stomach; air enters the larynx anteriorly. During swallowing, food has the "right of way", and air passage temporarily stops.

Gallery

Conducting passages.	Organs of the digestive system.	The entrance to the larynx, viewed from behind.	Sagittal section of nose mouth, pharynx, and larynx.
The position and relation of the esophagus in the cervical region and in the posterior mediastinum. Seen from behind.

References

• Stedman's/LWW 1551471
• Human Anatomy and Physiology Elaine N. Marieb and Katja Hoehn, Seventh Edition.
• TNM Classification of Malignant Tumours Sobin LH & Wittekind Ch (eds)Sixth edition UICC 2002 ISBN 0-471-22288-7

See also

• Adenoid
• Eustachian tube
• Hyoid
• Larynx
• Tonsil
• Uvula

External links

• SUNY Labs 31:st-1401