The Anatomy of the Pharynx

Tube used by both the respiratory and digestive systems

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The pharynx is most commonly referred to as the throat, a muscular tube that starts at the base of the skull behind the nasal cavity and extends down to the larynx and esophagus. Its primary function serves both the respiratory system by taking in air from the nasal cavity as well as the digestive system by taking food and drink from the oral cavity. The pharynx is also what helps you speak, as the muscles from the pharynx vibrate to help produce sound.

Anatomy

Structure and Location

The pharynx consists of three major sections: the nasopharynx, the oropharynx, and the laryngopharynx. These sections are in order down the pharynx, as the nasopharynx is the top part of the throat, located behind the nasal cavity, the oropharynx makes up the middle part behind the oral cavity, and the laryngopharynx as the bottom piece, which is behind the larynx (commonly referred to as the voice box). The pharynx as a whole is about 5 centimeters (cm) in length. While the tube is largely hard tissues, some areas like the oropharynx consist of soft tissue.

Certain parts of the pharynx are also made up of different cells and muscles. For example, the nasopharynx is made up of respiratory epithelium, a protective mucous membrane that coats the airways and respiratory tract. The nasopharynx is also where the adenoid tonsils are located, a patch of tissue high up in the throat that makes up some of your tonsils. The oropharynx contains not only the rest of your tonsils (known as the lingual and palatine tonsils) but also the rear third of your tongue and a constrictor muscle, which helps you swallow.

Last, the laryngopharynx contains two groups of constrictor muscles as well—a middle pharyngeal constrictor and inferior pharyngeal constrictor. Together these muscles help push food down into the esophagus for digestion.

Aside from the constrictor muscles (which are more circular in shape) the pharynx also has several longitudinal muscles that shorten and expand the pharynx as well as push the larynx up when swallowing. These muscles are called the stylopharyngeus, palatopharyngeus, and salpingopharyngeus. In addition to muscles, the pharynx is made up of a network of nerves, including the pharyngeal plexus, glossopharyngeal nerve, and vagus nerve. These nerves are responsible for the pharynx’s motor and sensory functions, things like swallowing, grasping food, and pushing it down into the esophagus. If swallowing seems like it’s a complicated function, that’s because it is. In fact, it takes approximately 25 pairs of muscles in the mouth, pharynx, larynx, and esophagus to do this.

Anatomical Variations

For the pharynx to work properly, its location has to be precise. By being in the middle of the neck it is able to assist the respiratory and digestive tracts equally. Any muscular changes in the pharynx may affect its location, whether it be longitudinal muscles attached incorrectly or missing muscles. Previous research has found that the salpingopharyngeus muscle was only present in 63% of cadavers, with a majority of those individuals being thin. This could alter the location of the pharynx even slightly, which may affect (whether it is noticeable or not) airflow and/or digestion.

Function

Because of its location, the pharynx helps the respiratory system by allowing air to make its way to the respiratory tract. For digestion, the use of the muscles surrounding the pharynx (both circular constrictive muscles and longitudinal muscles) work together to send food and drink down to the esophagus. The circular muscles push food and drink down to the intestines while the longitudinal muscles widen and lift the pharynx, which is what makes it possible to swallow.

The less-known function of the pharynx is its role in speech. Because the pharynx is an enclosed space that can change shape thanks to its musculature structure, air is able to travel through the pharynx to the larynx (the voice box). As vocal cords work to make sound the pharynx is able to amplify that sound as the larynx opens up into the pharynx.

Associated Conditions

Conditions related to the pharynx range from mild to severe. Things like a sore throat from a virus or cold, allergies, strep throat, or gastroesophageal reflux disease (GERD) can all affect the pharynx and leave you feeling uncomfortable. Thankfully, there are both over-the-counter and prescription remedies that treat a majority of these common ailments to heal the pharynx quickly. In many cases, these issues may go away on their own. Other conditions may require treatment, with a sore throat as one of the leading symptoms. This includes:

If you have a persistent sore throat that doesn’t go away after a few days to a week, it’s a good idea to make an appointment with a healthcare provider to pinpoint this issue. While it’s OK to try over-the-counter sore throat remedies (or natural ones such as gargling warm salt water), don’t ever take antibiotics that aren’t prescribed to you as a means to treat a sore throat. Antibiotics only treat bacterial infections, and depending on the cause of your sore throat these meds may do more harm (such as building up antibiotic resistance) than good for you.

Tests

In order for your healthcare provider to determine the cause of your pharynx pain, some additional tests may be needed. This includes a laryngoscopy, which lets your doctor look at the larynx and pharynx using a small device that has a telescope on it inserted into either the nose and down into the throat or directly through the pharynx itself. If you have a chronic cough or sore throat, voice changes, or difficulty breathing a laryngoscopy may be the next step in determining the cause behind these symptoms.

Other tests that may be needed aren’t necessarily because of the pharynx itself, but the symptoms of a sore throat lead to it, such as a pH test for acid reflux, barium swallow to detect abnormalities in the digestive tract and throat, or esophageal manometry test used to diagnose any issues with the esophagus.

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