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The pharynx, commonly known as the throat, is a 12-14cm long fibromuscular tube that connects the nasal and oral cavities to the oesophagus and larynx. It is divided into three sections: the nasopharynx, oropharynx, and laryngopharynx. The pharynx serves as a conduit for air, food, and liquids to travel from the nose and mouth to the lungs and stomach, and is therefore essential to the digestive and respiratory systems. The pharynx also plays a role in speaking and swallowing, with the help of its two sets of muscles. These muscles are the three pharyngeal constrictor muscles, and the three vertically oriented muscles: the stylopharyngeus, salpingopharyngeus, and palatopharyngeus. The pharyngeal muscles are innervated by the vagus nerve, except for the stylopharyngeus, which is innervated by the glossopharyngeal nerve.
| Characteristics | Values |
|---|---|
| Description | The pharynx is a fibromuscular tube that is semicircular in cross-section and situated directly anterior to the vertebral column. |
| Function | The pharynx facilitates the passage of air, solids, and liquids from the nose and mouth. It functions in both the digestive and respiratory systems. |
| Muscles | The pharynx has two sets of muscles: three pharyngeal constrictor muscles and three vertically oriented muscles (stylopharyngeus, salpingopharyngeus, and palatopharyngeus). |
| Muscle Function | The pharyngeal constrictor muscles constrict the pharyngeal lumen, propelling food into the oesophagus. The vertically oriented muscles shorten and widen the pharynx and elevate the larynx during swallowing. |
| Muscle Innervation | Most muscles of the pharynx are innervated by the vagus nerve (CN X). The stylopharyngeus muscle is innervated by the glossopharyngeal nerve (CN IX). |
| Blood Supply | The pharynx receives blood supply from four main arteries, all originating from the external carotid artery. |
| Venous Drainage | The pharyngeal venous plexus drains into the internal jugular vein. |
| Lymphatic Drainage | Lymphatic drainage occurs in the deep cervical nodes. |
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What You'll Learn
- The pharynx is a fibromuscular tube with three constrictor muscles
- The pharyngeal plexus is the main nervous plexus supplying the pharynx
- The pharynx is divided into three sections: nasopharynx, oropharynx, and laryngopharynx
- The pharynx is essential for swallowing, with six muscles aiding this process
- The pharynx is highly vascularised, with a rich amount of arterial anastomoses
The pharynx is a fibromuscular tube with three constrictor muscles
The pharynx is a fibromuscular tube that is semicircular in cross-section and is situated directly anterior to the vertebral column. It extends from the skull base to the lower border of the cricoid cartilage. The pharynx is part of the digestive system and is posterior to the oronasal cavity and larynx. The pharyngeal muscles are organised into an outer circular layer and an inner longitudinal layer surrounding the lumen.
The outer circular layer consists of three pharyngeal constrictor muscles: the superior, middle, and inferior pharyngeal constrictors. These muscles are arranged like stacked glasses, forming an incomplete muscular circle around the pharynx. They contract sequentially from superior to inferior to constrict the pharyngeal lumen and propel food into the oesophagus. The superior pharyngeal constrictor, the uppermost constrictor, is located in the oropharynx and originates from the pterygomandibular ligament, alveolar process of the mandible, medial pterygoid plate, and pterygoid hamulus of the sphenoid bone. It inserts posteriorly onto the pharyngeal tubercle of the skull base and the pharyngeal raphe.
The middle pharyngeal constrictor is located in the laryngopharynx and originates from the stylohyoid ligament and the horns of the hyoid bone. It inserts posteriorly into the pharyngeal raphe. The inferior pharyngeal constrictor is located in the laryngopharynx and has two components: thyropharyngeal fibres, which originate from the thyroid cartilage, and cricopharyngeal fibres, which originate from the cricoid cartilage. All fibres insert posteriorly onto the pharyngeal raphe.
The inner longitudinal layer consists of the palatopharyngeus, salpingopharyngeus, and stylopharyngeus muscles. These muscles act to shorten and widen the pharynx and elevate the larynx during swallowing. The stylopharyngeus originates from the styloid process of the temporal bone and inserts onto the pharyngeal wall. Unlike the other pharyngeal muscles, it is innervated by the glossopharyngeal nerve (CN IX) instead of the vagus nerve (CN X). The palatopharyngeus originates from the hard palate of the oral cavity and inserts onto the pharyngeal wall. It is innervated by the vagus nerve (CN X). The salpingopharyngeus originates from the Eustachian tube and inserts onto the pharyngeal wall. It is also innervated by the vagus nerve (CN X).
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The pharyngeal plexus is the main nervous plexus supplying the pharynx
The pharynx is a muscular tube that connects the nasal cavities to the larynx and oesophagus. It is made up of three cavities: the nasopharynx, oropharynx, and laryngopharynx. The pharyngeal plexus is the main nervous plexus supplying the pharynx. The pharyngeal plexus is a nerve plexus located on the outer surface of the pharynx. It provides motor, sensory, and sympathetic innervation to the majority of the pharynx. The pharyngeal plexus is formed by the glossopharyngeal nerve (CN IX), the vagus nerve (CN X), and the sympathetic chain.
The glossopharyngeal nerve (CN IX) provides sensory innervation to the pharynx, while the vagus nerve (CN X) provides motor innervation to all the muscles of the pharynx, except for the stylopharyngeus muscle, which is innervated by the glossopharyngeal nerve. The stylopharyngeus muscle elevates and expands the pharynx laterally. The vagus nerve also provides motor innervation to the larynx, but this is not through the pharyngeal plexus.
The pharyngeal plexus sits on the posterolateral surface of the middle pharyngeal constrictor muscle. The pharyngeal constrictor muscles are arranged like stacked glasses, forming an incomplete muscular circle around the pharynx. They contract sequentially from superior to inferior to constrict the pharyngeal lumen and propel food into the oesophagus. The superior pharyngeal constrictor is the uppermost pharyngeal constrictor, located in the oropharynx. The middle pharyngeal constrictor is located in the laryngopharynx, and the inferior pharyngeal constrictor is also located in the laryngopharynx.
The pharyngeal plexus also provides innervation to other pharyngeal muscles, including the palatopharyngeus, palatoglossus, musculus uvulae, and salpingopharyngeus. The palatopharyngeus originates from the hard palate of the oral cavity and inserts onto the pharyngeal wall. It is innervated by the vagus nerve. The salpingopharyngeus originates from the Eustachian tube and inserts onto the pharyngeal wall. It is also innervated by the vagus nerve. The venous drainage of the pharynx is achieved by the pharyngeal venous plexus, which drains into the internal jugular vein.
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The pharynx is divided into three sections: nasopharynx, oropharynx, and laryngopharynx
The pharynx is a muscular column that runs between the oral cavity and the oesophagus. It is divided into three sections: the nasopharynx, oropharynx, and laryngopharynx.
The nasopharynx is the first section of the pharynx, followed by the oropharynx, and then the laryngopharynx. The laryngopharynx is the third and final part of the pharynx and is a continuation of the oropharynx at the upper border of the epiglottis. It extends down to the lower border of the cricoid cartilage, where it becomes continuous with the oesophagus. This section functions as a passageway for both food/water and air and is lined with stratified squamous epithelium. The anterior wall of the laryngopharynx is incomplete, with the laryngeal inlet (aditus) situated anteriorly, separating the pathways for digestion and respiration.
The pharyngeal muscles are made up of three constrictor muscles that run circularly on the outside and longitudinally on the inside. These constrictor muscles have several gaps between their folds, allowing structures such as nerves, arteries, and veins to pass through. For example, the stylopharyngeus muscle, which functions to elevate and expand the pharynx laterally, passes between the superior and middle pharyngeal constrictor muscles.
The pharyngeal plexus is the main nervous plexus supplying the pharynx. The sensory branches originate from the glossopharyngeal nerve, which also supplies the stylopharyngeus muscle. The tonsillar nerves carry fibres from both the glossopharyngeal nerve and the vagus nerve. The motor branches come from the pharyngeal plexus and carry fibres from the vagus nerve, providing motor innervation to all the muscles of the pharynx and the soft palate, except for the stylopharyngeus and tensor veli palatini muscles.
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The pharynx is essential for swallowing, with six muscles aiding this process
The pharynx is a complex structure, a muscular column that runs between the oral cavity and the oesophagus. It is essential for swallowing, with six muscles aiding this process.
Firstly, the pharyngeal muscles contract involuntarily in a sequence known as peristalsis, which helps push food down from the oral cavity and into the oesophagus. This occurs during and immediately after swallowing. The pharyngeal muscles also assist in other functions, including phonation and the maintenance of pharyngeal patency during inspiration.
Secondly, the pharyngeal walls are made up of muscles that run both circularly on the outside and longitudinally on the inside. The three pharyngeal constrictor muscles—the superior, middle, and inferior—form the outer layer of the wall. The inner layer is made up of three paired muscles: the stylopharyngeus, the palatopharyngeus, and the salpingopharyngeus. These muscles act as a group to elevate the larynx, shorten the pharynx, and aid in swallowing and speaking.
Thirdly, the stylopharyngeus muscle originates from the styloid process of the temporal bone and inserts onto the pharyngeal wall. It is innervated by the glossopharyngeal nerve (CN IX) and functions to elevate and expand the pharynx. The palatopharyngeus muscle originates from the hard palate of the oral cavity and inserts onto the pharyngeal wall. It is innervated by the vagus nerve (CN X) and draws the velum down. The salpingopharyngeus muscle originates from the cartilage of the auditory tube and elevates the pharynx and opens the auditory tube during swallowing.
Finally, the cricopharyngeal muscle is an important single muscle that lies at the transition level between the pharynx and the oesophagus. It acts as a sphincter, relaxing to allow the passage of food from the pharynx into the oesophagus.
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The pharynx is highly vascularised, with a rich amount of arterial anastomoses
The pharynx is a muscular column that runs between the oral cavity and the oesophagus. It is divided into three main sections: the nasopharynx, oropharynx, and laryngopharynx. The pharynx is highly vascularised, with a rich amount of arterial anastomoses. This means that it has a large number of interconnected arteries that supply blood to the region.
Four main arteries are responsible for the blood supply to the pharynx. All of them originate from the external carotid artery and supply the pharynx by either passing close to it or sending out ascending and descending pharyngeal arteries. The venous drainage of this region is via the external palatine vein, which drains into the pharyngeal plexus and then into the internal jugular vein.
The ascending pharyngeal artery is a small but important artery that supplies multiple cranial nerves and anastomotic channels to the anterior and posterior cerebral circulations. It is crucial in several clinical situations, such as trauma, epistaxis, and tumours in the head and neck region. The ascending pharyngeal artery also has a role in angiography and embolization techniques used in the evaluation and treatment of diseases in the head and neck region.
In addition to the ascending pharyngeal artery, there are several other arteries closely related to the pharynx. These include the ascending palatine artery, lingual artery, tonsillar artery, greater palatine artery, artery of the pterygoid canal, superior laryngeal artery, and inferior laryngeal artery. These arteries provide a rich blood supply to the pharynx and its surrounding structures, ensuring adequate oxygenation and nutrient delivery to the area.
The pharynx is a complex anatomical structure with a variety of muscles, arteries, and nerves working together to facilitate essential functions such as swallowing and speech. The rich vascularisation of the pharynx, with its numerous arterial anastomoses, ensures that the region receives an adequate blood supply to support these vital functions.
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Frequently asked questions
The pharynx is a fibromuscular tube that is semicircular in cross-section and situated directly anterior to the vertebral column. It is also known as the throat and is a continuous muscular passage for air, food, and liquids to travel down from your nose and mouth to your lungs and stomach.
The pharyngeal muscles are of two types: longitudinal and circular. The longitudinal muscles are the stylopharyngeus, palatopharyngeus, and salpingopharyngeus. The circular muscles are the superior, middle, and inferior pharyngeal constrictors.
The pharyngeal muscles help push food down the digestive tract, facilitate peristalsis, and aid in swallowing and speaking.
