Logo

Pharynx

The pharynx (Latin: pharynx), also known as the throatis a funnel-shaped muscular organ providing the intersection of air and feed paths and a passageway for the air, liquids, and food to move further to the lower respiratory and digestive system organs. It connects oral and nasal cavities with the esophagus and larynx. The pharynx locates in the head and neck areas posterior to mentioned cavities and above the esophagus and larynx.

Pharynx anatomy

The pharynx is approximately 12-15 centimeters (4.72- 5.91 inches) long, and its superior border goes to the external cranial base, but inferior ends at the sixth cranial vertebra level (C6). The upper part is broader, but the lower portion is narrower.

Superior and anterior to pharynx is the nasal cavity, but inferior it continuous with the esophagus

Anterior is the oral cavity and larynxPosterior to the pharynx is the cervical part of the spine, the neck's deep muscles, the cervical fascia layer, and retropharyngeal space. Along the lateral wall goes blood vessels and nerves.

Pharynx parts

The pharynx has three anatomical parts. Superior to inferior, they are- nasopharynx, oropharynx, and laryngopharynx.

Nasopharynx

The nasopharynx is the nasal part of the pharynx. It is the most upper part or superior division of the pharynx. It locates at the first and second cervical vertebrae level (C1-2), posterior and inferior to the nasal cavity. This part extends from the external cranial base to the free edge of the soft palate

Nasopharynx upper part firmly connects with the body of the sphenoid bone. The connection is known as the vault of the pharynx or pharyngeal fornix. The nasopharynx is involved in respiratory processes, and it is related to the respiratory system.

Superior attachment line to the skull

The pharynx attachment line to the external cranial base goes from the pharyngeal tubercle of the occipital bone in both sides' frontal direction. It crosses the basilar part of the occipital bone and goes on the inferior surface of the temporal bone's petrosal part along the external carotid foramen's anterior side. Next, the pharynx's anterior edge turns forward, and medially, it reaches the base of the pterygoid processes medial plate and firmly fuses with its margin.

Walls and anatomical landmarks

The anterior wall contains two nasal cavity's posterior openings- choanae. Mentioned openings connect the pharynx with the nasal cavity. On both sides in the middle of the lateral wall, locate the auditory tube's pharyngeal opening connecting the pharynx with the tympanic cavity in the middle ear. 

The air gets to the cavity with the auditory tube's help, and it helps to equalize the pressure on both tympanic membrane sides as the tympanic membrane locates between the outer and middle ear. The opening also helps provide drainage of the middle ear in case of disorders.

Around the auditory tube's pharyngeal opening, more on the sides and in its superior part locate the torus tubarius, elevations made by mucosa covering the cartilaginous portion of the Eustachian tube. In the posterior wall, behind the torus tubarius finds the pharyngeal recess, also known as Rosenmuller recess, but more below the auditory tube's pharyngeal opening and going downwards- torus levatorius, fold overlying levator veli palatini muscle. Down to it, locate two more folds-the closest one overlies the palatopharyngeal sphincter. The second one is the salpingopharyngeal fold. On the borderline between the superior and posterior wall (posterosuperior) and above the torus tubarius locate unpaired pharyngeal tonsil, also known as the adenoid tonsil. 

Paired tubal tonsil, also known as the Gerlach's tonsil, locates around and next to the auditory tube's pharyngeal opening.

Oropharynx

The oropharynx is the middle part, located posterior to the oral cavity, and is its continuation. 

It locates at the level of the third and fourth cervical vertebrae (C3-4). It extends from the soft palate's free edge to the superior border of the epiglottis. 

This part has only one opening anteriorly. It is called the oropharyngeal isthmus or the oropharyngeal opening; also, the isthmus of fauces. It connects the oropharynx with the oral cavity. To sum up, uvula, palatine, and lingual tonsils, the tongue's root, and palatopharyngeal arch form the opening.

The oropharynx includes palatine and lingual tonsils, the tongue's root part, and the superior constrictor muscle.

The oropharynx is involved in respiratory and digestion processes, and it is related to the respiratory and digestive systems.

Waldeyer's tonsillar ring

It is a lymphoid tissue aggregation ring in the border of oral and nasal cavities and pharynx. It forms the tonsillar ring and provides the first line immunologic function by protection and defense against various antigens entering through the nasal and oral cavities. The ring protects both tracts- the respiratory and gastrointestinal.

It consists of six tonsils- two unpaired and two paired. Pharyngeal and lingual tonsils don't have pairs, but palatine and tubal tonsils have right and left aspects.

The upper part of the ring forms the single pharyngeal tonsil, but the inferior part includes the lingual tonsil. In lateral part's formation help tubal tonsils more superiorly and palatine tonsils inferiorly.

Laryngopharynx

Laryngopharynx is also known as the hypopharynx. It is the bottom, the most distal, and the last part of the pharynx. It locates at the level of the fifth and sixth cervical vertebrae (C5-6). It starts from the epiglottis's superior edge and goes until the esophagus entrance, extending to the cricoid cartilage's inferior border. 

Hypopharynx in the inferior direction continues with the esophagus. Anteriorly is the larynx.

Hypopharynx has two openings- the laryngeal inlet (also known as the laryngeal aditus) and the esophageal opening. The first one connects the pharynx with the airways, but the second connects the pharynx with the esophagus.

On the sides of the laryngeal inlet locate piriform fossa or sinus, a slight depression in the pharynx's lateral walls extending from the pharyngoepiglottic fold to the esophageal opening. In the submucosa of the sinus goes internal and recurrent laryngeal nerve. Piriform fossa is a common site for entrapment of foreign bodies, and nerves can get injured during the removal procedure.

The fossa medially borders with aryepiglottic fold and posterolateral surfaces of arytenoid and cricoid cartilages. Laterally it ends with thyroid membrane and thyroid cartilage.

The laryngopharynx is involved in respiratory and digestion processes, and it is related to the respiratory and digestive systems.

Muscular pharynx

The pharynx contains two groups of very well-developed skeletal muscles. 

All muscles have pairs, and the following groups are:

  • muscles constricting the pharynx or circular muscles
  • longitudinal muscles or the muscles that lift the pharynx.

Muscles of the pharynx, together with tongue, soft palate, and larynx, help move and swallow the food as the soft palate elevates and closes the passage to the nasal cavity. Epiglottis depresses and closes the airways, allowing the food bolus's movements further in the esophagus by tongue and pharynx muscles.

Constrictor muscles

All constrictor muscles have the same function- they constrict and narrow the pharynx. All constrictor muscles are circular muscles because going from the anterior part of the pharynx to its sides and ending posteriorly in the neck's midline. Fibers form an incomplete circle.

All muscles make wave-like consecutive contractions from superior to inferior parts helping in the swallowing and food bolus moving

All muscle fibers from both sides connect in the middle of the posterior wall forming the median pharyngeal raphe extending downwards from the external cranial base.

  • The superior pharyngeal constrictor is the most superior muscle, and it locates in the oropharynx part. It starts at the medial plate of the pterygoid process of the sphenoid bone, pterygoid hamulus, pterygomandibular raphe, and posterior end of mylohyoid line and lingula of the mandible. Fibers go to the occipital bone's pharyngeal tubercle and median pharyngeal raphe.
  • Medial pharyngeal constrictor starts at hyoid bone's horns and stylohyoid ligament, fibers go in opposite directions- up and downwards, forming a fan-shaped form. They insert at pharyngeal raphe. The upper aspect partially covers the superior pharyngeal constrictor muscle's lower part, and the medial pharyngeal constrictor has a rhombus shape. Medial constrictors locate primarily in the laryngopharynx.
  • Inferior pharyngeal constrictor goes from thyroid and cricoid cartilages to pharyngeal raphe. The same as the previous ones, these muscle fibers extend in various directions, and they also have a fan-shaped form. The upper aspect partially covers the medial pharyngeal constrictor muscle's lower fibers. It also has a rhombus shape, and it primarily locates in the hypopharynx.

Levator muscles

Levator muscles are longitudinal muscles. All muscles elevate the pharynx during swallowing by shortening and widening it.

  • Stylopharyngeaus muscle starts at the temporal bone's styloid process and inserts in the lateral pharynx wall.
  • The Palatopharyngeus muscle not only acts by making movements in the pharynx. Muscle also shortens the palatopharyngeal arch and narrows the oropharyngeal isthmus, tenses the soft palate. Muscle fibers start in palatine aponeurosis and hard palate. They go by the palatopharyngeal arch, ending in the pharynx's lateral sides and the thyroid cartilage's superior border.
  • Salpingopharyngeus muscle helps in pressure-equalizing in the middle ear as it helps to open the auditory tube during swallowing. It origins from the Eustachian tube and ends in the pharynx lateral walls blending with palatopharyngeus muscle fibers.

Microanatomy

The pharynx is a muscular and fibrous organ

Its wall consists of 4 layers:

  • the mucous membrane, 
  • submucosa with pharyngobasilar fascia, 
  • muscular layer with pharyngeal muscles, 
  • adventitia part.

The mucosa covers all pharynx parts and, in some regions, forms plicas or mucosal folds. The pharynx has two different types of mucosal epithelium

The nasal cavity part has the respiratory epithelium, and it is the continuation of the nasal cavity's mucosa covered by ciliated epithelium. The nasopharynx part epithelium is the ciliated pseudostratified columnar, containing mucus-producing goblet cells. Other parts line the squamous stratified non-keratinized epithelium. 

Connective tissue contains many blood vessels and is very vascular. 

The pharynx contains many mucus-producing pharyngeal glands and mucosa-associated lymphoid tissue aggregates that include B and T lymphocytes and macrophages, protecting against the antigenes. As mentioned above pharynx also has three tonsils- two tubal and one pharyngeal. 

The upper two-thirds has a very well-developed and thick connective tissue layer getting thinner in the esophagus direction.

The inner muscular layer contains longitudinal fibers, but the outer- circular skeletal muscle fibers.

Functions

The pharynx's primary function is to provide air and food passage from the oral and nasal cavities to digestive and respiratory system parts. Primary, it is involved in digestion and breathing processes.

  • Pharynx muscles provide the peristalsis and food bolus moving from the oral cavity further in the gastrointestinal tract, while longitudinal muscles allow to swallow it. 
  • The pharynx is a part of the vocal system, and its form and shape help make various speech sounds and help in voice production and resonance.
  • As the pharynx can contain a small number of taste buds, it also participates in taste sensation creation.
  • Pharynx takes part in air conditioning.
  • Pharynx mucosa with lymphoid tissue aggregates helps to provide local immunity and defense against various harmful antigenes.
  • The pharynx provides drainage for secretion for nasal and oral cavities and the middle ear.
  • Help in the pressure equalization on both tympanic membrane sides.

Neurovascular supply

Arterial blood supply

  • The arterial blood supply for the pharynx provides ascending pharyngeal artery, a branch of the external carotid artery.
  • Arterial blood perfusion also provides dorsal lingual branch from the lingual artery and ascending palatine artery and tonsillar branches from the facial artery. Both are branches of the external carotid artery. 
  • Small pharyngeal branches from the inferior thyroid artery also perfuse the pharynx. The inferior thyroid artery is a branch from the thyrocervical trunk.
  • External carotid artery's terminal branch- a maxillary artery and its branches (greater palatine, pharyngeal and pterygoid arteries) also perfuse pharynx. 

Venous drainage

Venous drainage for the pharynx provides the pharyngeal plexus carrying blood next to facial and pharyngeal veins and then to the internal jugular vein.

Lymphatic drainage

Pharyngeal lymphatic vessels drain mostly directly into deep cervical nodes or indirectly via the retropharyngeal located behind the pharynx, paratracheal (along the sides of the trachea), and via infrahyoid lymph nodes.

Innervation

Sensory and motor innervation mainly provides the pharyngeal plexus. It makes the pharyngeal branches of the glossopharyngeal nerve (CN IX), vagus nerve (CN X), and sympathetic trunk's cervical part's superior cervical ganglion fibers.

Motor innervation

All pharyngeal muscles, except the stylopharyngeus muscle, innervates fibers from the vagus nerve (CN X). 

Stylopharyngeus muscle innervates same-named branches from the glossopharyngeal nerve (CN IX).

Sensory innervation

Mainly pharynx receives the innervation from the glossopharyngeal nerve (CN IX). However, the nasopharynx and hypopharynx innervation involve two more nerves.

The upper nasopharynx part innervates branches from the maxillary nerve (CN V2)

The sensory innervation oropharynx primarily receives from the glossopharyngeal nerve (CN IX) branches.

The Vagus nerve (CN X) innervates only the hypopharynx's inferior part. Innervation supplies the internal laryngeal branch from the superior laryngeal nerve. 

Pharynx diseases

Disorders affecting the pharynx are common as, for example, almost always a common cold presents with it. 

The most common part involved is the oropharynx. Most of the cases are self-limiting and don't need specific treatment. Conditions can affect only the pharynx, or pharynx involvement with presenting symptoms can sign a systemic disease.

Pharyngitis 

Pharyngitis, also know as the sore throat, is the inflammation of the pharynx. 

Causes and risk factors

The most common cause is viral etiology. Pharyngitis can present in cases of the common cold, flu, chickenpox, croup, COVID-19, HIV, and many more to follow. 

The most common bacterial agent causing pharyngitis is Streptococcus, and the condition is called strep throat.

Pharyngitis can also cause:

  • gastroesophageal reflux disease (GERD) or acid reflux in which the acid from the stomach regularly or periodically flows back in the esophagus and throat because of the weak lower oesophageal sphincter,
  • allergic agents,
  • dryness caused by systemic disorders such as Sjogren's disease or by environmental factors,
  • immunosuppression,
  • pollution,
  • various irritants such as tobacco or a large amount of alcohol consumption,
  • pharynx muscle overwork by speaking too long or too loud,
  • cancers.

The risk factors include children and young adults, existing allergies, frequent nose or nose sinus infections, and other existing disorders.

Symptoms

It characterizes by a red and painful throat, discomfort, scratchiness sensation, and irritation, usually in the oropharynx area, issues with swallowing or dysphagia, as well as runny nose, a dry cough can be present. Symptoms typically worsen during swallowing or talking. Pharyngitis can present with enlarged regional lymph nodes and swollen tonsils. Sometimes voice changes, usually hoarse voice, can be present. General symptoms such as weakness, malaise, muscle aches, fever, and headaches can be present depending on the causing factor.

Treatment and prevention

The treatment depends on the causing agent, but usually, the condition is self-limiting without any specific treatment. Nonsteroidal anti-inflammatory drugs can reduce pain and inflammation. In case of bacterial infection, the particular treatment includes antibiotics. Usually, there are no complications, but untreated strep throat can lead to more severe glomerulonephritis or rheumatic fever.

Prevention includes regular hand washing, avoidance of sick people and shared food or dishes, usage of hand sanitizers, especially when in public. Prevention includes practicing good coughing and sneezing hygiene.

Enlarged adenoids

Enlarged adenoids present as swollen and enlarged pharyngeal tonsils. Usually, the inflammation is secondary to an infection. 

Enlarged adenoids affect breathing as they make it hard to breathe through the nose, resulting in breathing through the mouth.

Adenoids start to decrease in size around the age of 4 to 5 years, and around teenage years, they are tiny. It is the reason why enlarged adenoids usually have only children.

Adenoids present with mouth dryness and cracked lips, full feeling in the nasal cavity, runny noseSleep apnoea, sleep issues, snoring, and loud breathing can be present. Enlarged adenoids can result in ear infections.

Treatment depends on the etiology of the factors. Sometimes adenectomy or adenoid removal surgery can be performed.

Obstructive sleep apnoea

Obstructive sleep apnea is a potentially life-threatening condition characterized as repeatedly stopped breathing during sleep. Sleep apnoea presents with several types, but the most common is the obstructive type.

Causes

Obstructive sleep apnoea happens when pharynx muscles lose their tone and become hypotonic and relaxed during sleep resulting in airway narrowing and blockage during the inhalation. 

It can happen a few to even 40 times per hour, resulting in an inability to reach the deep sleep phase. It can result in a feeling of lack of sleep, although individuals have slept more than necessary.

Symptoms

Symptoms usually include snoring, choking and gasping air during sleep, drowsiness during the day, and fatigue, insomnia during the night. Another person can report episodes of stopped breathing during sleep. Headaches, dry mouth can be present. During the day, it can be hard to concentrate, and there can be mood swings.

Risk factors and complications

The most common risk factors are:

  • obesity, 
  • large tongue or issues causing its enlargement,
  • large, thick, and short neck,
  • narrow airways,
  • smoking,
  • older age,
  • gender (man are more likely to have it)
  • family history,
  • muscle relaxant substances and medications such as sedatives or alcohol,
  • disorders affecting the nose,
  • other diseases such as diabetes, hypertension, or asthma.

Some of the complications and issues caused by obstructive sleep apnoea include constant fatigue, hypertension or heart disorders, a higher chance of stroke, depression, problems with performing surgeries, and complications after them.

Summary on pharynx

What is the pharynx in the human body?

The pharynx is a funnel-shaped muscular organ that intersects air and feed paths, providing a passageway for the air, liquids, and food.

Is the pharynx the throat?

Yes, the pharynx is also known as the throat.

What is another word for pharynx?

Another word for the pharynx is the throat.

Where is the pharynx?

The pharynx locates in the head and neck areas posterior to nasal and oral cavities and above the esophagus and larynx. Its superior border goes to the external cranial base, but inferior ends at the sixth cranial vertebra level (C6).

What are the three parts of the pharynx?

The three anatomical parts of the pharynx are the nasopharynx, oropharynx, and hypopharynx or laryngopharynx.

Is the nasopharynx part of the throat?

Yes, the nasopharynx is the part of the throat. It is the most upper part of the pharynx, located posterior to the nasal cavity.

What blocks the nasopharynx during swallowing?

Nasopharynx during swallowing blocks the soft palate as it elevates and blocks the passageway to the nasal cavity.

Does food pass through the nasopharynx during swallowing?

No, food doesn't pass through the nasopharynx during swallowing as the passageway to the nasal cavity blocks elevated soft palate.

What is the difference between nasopharynx, oropharynx, and laryngopharynx?

The pharynx has three anatomical parts. Superior to inferior, they are- nasopharynx, oropharynx, and laryngopharynx. Nasopharynx locates posterior to the nasal cavity, oropharynx posterior to the oral cavity, but laryngopharynx- posterior to the larynx.

What is the back of the throat?

The back of the throat is called the oropharynx.

Where is the oropharynx located?

The oropharynx locates posterior to the oral cavity and is its continuation. It finds at the level of the third and fourth cervical vertebrae (C3-4). It extends from the soft palate's free edge to the superior border of the epiglottis. 

What does the oropharynx mean?

The oropharynx is the middle part of the pharynx, and it locates posterior to the mouth cavity. It is the pharynx's mouth aspect.

Is the oropharynx part of the upper respiratory system?

Yes, the oropharynx classifies as the upper respiratory system's part. Air gets to the trachea crossing the oropharynx.

What is the meaning of muscular pharynx?

The pharynx sometimes is called the muscular pharynx as it contains a relatively large amount of very well-developed skeletal muscle fibers helping in swallowing and food bolus movements. 

What comes first- larynx or pharynx?

The first is the pharynx. The larynx locates anteriorly to the hypopharynx. The hypopharynx contains an opening called the laryngeal inlet, which connects the pharynx with the larynx.

What does the pharynx contain?

The pharynx is a muscular and fibrous organ. Its wall consists of 4 layers- the mucous membrane, submucosa, muscular layer, and adventitia part.

What is the function of the pharynx?

The pharynx's primary function is to provide air and food passage from the oral and nasal cavities to digestive and respiratory system parts. Primary, it is involved in digestion and breathing processes.

What is pharyngitis?

Pharyngitis, also know as the sore throatis the inflammation of the pharynx.

What are the symptoms of pharyngitis?

It characterizes by a red and painful throat, discomfort, scratchiness sensation, and irritation, usually in the oropharynx area, issues with swallowing or dysphagia, as well as runny nose, a dry cough can be present. Symptoms typically worsen during swallowing or talking. Pharyngitis can present with enlarged regional lymph nodes and swollen tonsils. Sometimes voice changes, usually hoarse voice, can be present. General symptoms such as weakness, malaise, muscle aches, fever, and headaches can be present depending on the causing factor.

What is the most common cause of pharyngitis?

The most common cause has a viral etiology. Pharyngitis can be present in the common cold, flu, chickenpox, croup, COVID-19, HIV, and many more to follow. 

Is pharyngitis strep throat?

Yes, it can be as the most common bacterial agent causing the pharyngitis is Streptococcus, and the condition is called strep throat.

What happens if pharyngitis is left untreated?

Usually, the condition is self-limiting without any specific treatment, and the outcome is good.

What are adenoids?

The pharyngeal tonsil is also known as the adenoid tonsil. Enlarged adenoids present with swollen and enlarged pharyngeal tonsils. Usually, the inflammation is secondary to an infection. 

What are the symptoms of adenoid problems?

Adenoids present with mouth dryness and cracked lips, full feeling in the nasal cavity, runny nose. Sleep apnoea, sleep issues, snoring, and loud breathing can be present. Enlarged adenoids can result in ear infections.

What are the warning signs of sleep apnea?

Symptoms usually include snoring, choking and gasping air during sleep, drowsiness during the day, and fatigue, insomnia during the night. Another person can report episodes of stopped breathing during sleep. Headaches, dry mouth can be present. During the day, it can be hard to concentrate, and there may be mood swings.

What are the leading causes of sleep apnea?

Obstructive sleep apnoea happens when pharynx muscles lose their tone and become hypotonic and relaxed during sleep resulting in airway narrowing and blockage during the inhalation. The most common risk factor is obesity.