Anatomy Of The Pharynx: Structures And Functions
The anatomy of the pharynx is simple, but before we get into the details, we need to know some aspects of this organ. The pharynx is a muscular duct that is located in front of the spine and behind the nasal passages, oral cavity and larynx.
It is an unequal and symmetrical organ with a length of about 14 centimeters in men and 13 centimeters in women. Its transverse diameter varies between 4 centimeters and no more than 2 centimeters at the lower end. We speak of the lower extremity because the pharynx is funnel-shaped.
This duct extends from the base of the skull to the lower edge of the sixth cervical vertebra, where it continues into the esophagus. It is divided into 3 sections, which we will explain in more detail in the course of the article. These sections are: the nasopharynx, the oropharynx and the laryngopharynx.
What are the functions of the pharynx?
According to what was published in the fifth edition of Physiology of the Gastrointestinal Tract , we can highlight 4 main functions for which this organ is responsible:
- It helps digest food through the contraction of the walls and the swallowing reflex, which pushes the food down towards the esophagus.
- It is involved in breathing, as the air inhaled through the mouth and through the nose passes through the trachea and from there to the lungs.
- Allows vocalization.
- Equalizes the air pressure in the middle ear, ensuring proper sound conduction.
Anatomy of the pharynx: the nasopharynx
The nasopharynx is the only part of this purely aerial organ. For this reason, it is the only anatomical structure of the pharynx that is permeable, as it is continuously open to the air. It is located in front of the cervical spine and under the base of the skull. It is also known as the nasopharynx.
It connects downward with other pharyngeal anatomical structures, such as the oropharynx and laryngopharynx. The nasopharynx consists of four parts:
- Anterior: the anterior wall of the nasopharynx is bounded by the posterior and inferior portion of the nasal septum (or vomer) and connects with the nasal cavities through the choanas.
- Posterior: in the mucosa of the posterior wall is the opening of the Eustachian tube that connects it with the middle ear.
- Upper: the upper limit is bounded by the skull, through the mucosa of the sphenoid bone. In children under the age of 12, adenoids are found in the upper wall of this anatomical structure of the pharynx. Adenoids are a tissue portion of our body’s lymphatic system.
- Inferior: This boundary is formed by the back and bottom of a bone called the palatine.
Anatomy of the pharynx: the oropharynx
It is the most complex pharyngeal section. The soft palate separates the nasopharynx from this structure, which regulates the passage of air and food through the pharynx. It is therefore able to:
- Limit pharyngo-nasal reflux
- Push the food bolus
- Facilitate the passage of air
- Participate in vocalization
Its upper limit is given by the soft palate, in the posterior part, by the vertebral column and by the prevertebral muscles. Below it is bounded by an imaginary plane that passes through the upper edge of the epiglottis.
As for the lateral limits, we find the tonsillar pits and the isthmus of the jaws that delimits the connection with the oral cavity. It can be said that the anatomy of the oropharynx is simple on the surface, but complex in depth.
Anatomy of the pharynx: laryngopharynx
Corresponds to the lowest portion of the pharynx. It is also called the hypopharynx and extends from the upper edge of the epiglottis to the lower edge of the cricoid cartilage.
Anteriorly it is connected to the larynx and on both sides there are two vertical depressions known as piriform sinuses. The food bolus goes down through these sinuses to the esophagus.
In conclusion
The anatomy of the pharynx is relatively simple, although it is an organ with important functions. It is divided into 3 sections: the nasopharynx, the oropharynx and the laryngopharynx. Together, these parts are essential for completing the vocalization, breathing and swallowing of the food bolus.
