anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...

, the adenoid, also known as the pharyngeal tonsil or nasopharyngeal tonsil, is the superior-most of the

tonsil The tonsils are a set of lymphoid organs facing into the aerodigestive tract, which is known as Waldeyer's tonsillar ring and consists of the adenoid tonsil, two tubal tonsils, two palatine tonsils, and the lingual tonsils. These organs play ...

s. It is a mass of

lymphatic tissue The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the immune system, and complementary to the circulatory system. It consists of a large network of lymphatic vessels, lymph nodes, lymphatic or lymphoid o ...

located behind the

nasal cavity The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nasal c ...

, in the roof of the

nasopharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struct ...

, where the

nose A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes th ...

blends into the

throat In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebrae. It contains the pharynx and larynx. An important section of it is the epiglottis, separating the esophagus from the trachea (windpipe ...

. In

child A child ( : children) is a human being between the stages of birth and puberty, or between the developmental period of infancy and puberty. The legal definition of ''child'' generally refers to a minor, otherwise known as a person younger ...

ren, it normally forms a soft mound in the roof and back wall of the nasopharynx, just above and behind the

uvula The palatine uvula, usually referred to as simply the uvula, is a conic projection from the back edge of the middle of the soft palate, composed of connective tissue containing a number of racemose glands, and some muscular fibers. It also conta ...

. The term ''adenoid'' is also used to represent

adenoid hypertrophy Adenoid hypertrophy (enlarged adenoids) is the unusual growth (hypertrophy) of the adenoid (pharyngeal tonsil) first described in 1868 by the Danish physician Wilhelm Meyer (1824–1895) in Copenhagen. He described a long term adenoid hypertrophy t ...

, the abnormal growth of the pharyngeal tonsils.

Structure

The adenoid is a mass of

located behind the nasal cavity, in the roof of the

, where the nose blends into the throat. The adenoid, unlike the

palatine tonsil Palatine tonsils, commonly called the tonsils and occasionally called the faucial tonsils, are tonsils located on the left and right sides at the back of the throat, which can often be seen as flesh-colored, pinkish lumps. Tonsils only present as ...

s, has

pseudostratified epithelium A pseudostratified epithelium is a type of epithelium that, though comprising only a single layer of cells, has its cell nuclei positioned in a manner suggestive of stratified epithelia. As it rarely occurs as squamous or cuboidal epithelia ...

. The adenoids are part of the so-called Waldeyer ring of lymphoid tissue which also includes the palatine tonsils, the

lingual tonsils The lingual tonsils are a collection of lymphatic tissue located in the lamina propria of the root of the tongue. This lymphatic tissue consists of the lymphatic nodules rich in cells of the immune system (immunocytes). The immunocytes initiate th ...

and the

tubal tonsils The tubal tonsil, also known as Gerlach tonsil, is one of the four main tonsil groups forming Waldeyer's tonsillar ring. Structure Each tubal tonsil is located posterior to the opening of the Eustachian tube on the lateral wall of the nasopha ...

Development

Adenoids develop from a subepithelial infiltration of

lymphocytes A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adap ...

after the 16th week of embryonic life. After birth, enlargement begins and continues until aged 5 to 7 years.

Microbiome

Species of bacteria such as

lactobacilli The ''Lactobacillaceae'' are a family of lactic acid bacteria. It is the only family in the lactic acid bacteria which includes homofermentative and heterofermentative organisms; in the ''Lactobacillaceae,'' the pathway used for hexose fermentati ...

, anaerobic streptococci,

actinomycosis Actinomycosis is a rare infectious bacterial disease caused by ''Actinomyces'' species. The name refers to ray-like appearance of the organisms in the granules. About 70% of infections are due to either '' Actinomyces israelii'' or '' A. gerencser ...

Fusobacterium ''Fusobacterium'' is a genus of anaerobic, Gram-negative, non-sporeforming bacteria belonging to Gracilicutes. Individual cells are slender, rod-shaped bacilli with pointed ends. Strains of ''Fusobacterium'' cause several human diseases, includin ...

species, and Nocardia are normally present by 6 months of age. Normal flora found in the adenoid consists of

alpha-hemolytic streptococci ''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs ...

and

enterococci ''Enterococcus'' is a large genus of lactic acid bacteria of the phylum Bacillota. Enterococci are gram-positive cocci that often occur in pairs (diplococci) or short chains, and are difficult to distinguish from streptococci on physical charac ...

, Corynebacterium species,

coagulase-negative staphylococci ''Staphylococcus'' is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical (cocci), and form in grape-like clusters. ''Staphylococcus'' species are facultativ ...

Neisseria ''Neisseria'' is a large genus of bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens, '' N. meningitidis'' and ''N. gonorrhoeae''. ''Neisseria'' species are Gram-negativ ...

species,

Haemophilus ''Haemophilus'' is a genus of Gram-negative, pleomorphic, coccobacilli bacteria belonging to the family Pasteurellaceae. While ''Haemophilus'' bacteria are typically small coccobacilli, they are categorized as pleomorphic bacteria because of ...

species,

Micrococcus ''Micrococcus'' (mi’ krō kŏk’ Əs) is a genus of bacteria in the Micrococcaceae family. ''Micrococcus'' occurs in a wide range of environments, including water, dust, and soil. Micrococci have Gram-positive spherical cells ranging from abo ...

species, and Stomatococcus species.

Clinical significance

Enlargement

An enlarged adenoid, or

, can become nearly the size of a

ping pong ball Table tennis, also known as ping-pong and whiff-whaff, is a sport in which two or four players hit a lightweight ball, also known as the ping-pong ball, back and forth across a table using small solid rackets. It takes place on a hard table div ...

and completely block airflow through the nasal passages. Even if the enlarged adenoid is not substantial enough to physically block the back of the nose, it can obstruct airflow enough so that breathing through the nose requires an uncomfortable amount of work, and inhalation occurs instead through an open mouth. The enlarged adenoid would also obstruct the nasal airway enough to affect the voice without actually stopping nasal airflow altogether. Symptomatic enlargement between 18 and 24 months of age is not uncommon, meaning that snoring, nasal airway obstruction and obstructed breathing may occur during sleep. However, this may be reasonably expected to decline when children reach school age, and progressive shrinkage may be expected thereafter.

Adenoid facies

Enlargement of the adenoid, especially in children, causes an atypical appearance of the face, often referred to as ''adenoid facies''. Features of adenoid facies include

mouth breathing Mouth breathing, medically known as chronic oral ventilation, is long-term breathing through the mouth. It often is caused by an obstruction to breathing through the nose, the innate breathing organ in the human body. Chronic mouth breathing ma ...

, an elongated face, prominent incisors,

hypoplastic Hypoplasia (from Ancient Greek :wikt:ὑπό, ὑπo- ''hypo-'' 'under' + πλάσις ''plasis'' 'formation'; adjective form ''hypoplastic'') is underdevelopment or incomplete development of a tissue or organ.maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

, short upper lip, elevated nostrils, and a high arched palate.

Removal

Surgical removal of the adenoid is a procedure called

adenoidectomy Adenoidectomy is the surgical removal of the adenoid for reasons which include impaired breathing through the nose, chronic infections, or recurrent earaches. The effectiveness of removing the adenoids in children to improve recurrent nasal sympto ...

. Adenoid infection may cause symptoms such as excessive

mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...

production, which can be treated by its removal. Studies have shown that adenoid regrowth occurs in as many as 19% of the cases after removal. Carried out through the mouth under a

general anaesthetic General anaesthetics (or anesthetics, see spelling differences) are often defined as compounds that induce a loss of consciousness in humans or loss of righting reflex in animals. Clinical definitions are also extended to include an induced coma ...

(or less commonly a

topical A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes ...

), adenoidectomy involves the adenoid being

curette A curette is a surgical instrument designed for scraping or debriding biological tissue or debris in a biopsy, excision, or cleaning procedure. In form, the curette is a small hand tool, often similar in shape to a stylus; at the tip of the cu ...

d, cauterized, lasered, or otherwise ablated. The adenoid is often removed along with the

s. Adenoidectomy more than doubles the relative risk of

chronic obstructive pulmonary disorder Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. The main symptoms include shortness of breath and a cough, which may or may not produce mu ...

and diseases of the upper respiratory tract, and nearly doubles the relative risk of

conjunctivitis Conjunctivitis, also known as pink eye, is inflammation of the conjunctiva, outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may ...

. Adenoidectomy without tonsillectomy increases the risk of

otitis media Otitis media is a group of inflammatory diseases of the middle ear. One of the two main types is acute otitis media (AOM), an infection of rapid onset that usually presents with ear pain. In young children this may result in pulling at the ear, ...

(2 to 4-fold) and increases the risk of

sinusitis Sinusitis, also known as rhinosinusitis, is inflammation of the nasal mucosa, mucous membranes that line the paranasal sinuses, sinuses resulting in symptoms that may include thick Mucus#Respiratory system, nasal mucus, a nasal congestion, plugg ...

In popular culture

In 1861

George Catlin George Catlin (July 26, 1796 – December 23, 1872) was an American adventurer, lawyer, painter, author, and traveler, who specialized in portraits of Native Americans in the United States, Native Americans in the Old West. Traveling to the We ...

published many engravings illustrating adenoid facies and its complications in his book ''Breath of Life'', where he advocated nose-breathing. In his 1984 autobiographical book '' Boy: Tales of Childhood'', author

Roald Dahl Roald Dahl (13 September 1916 – 23 November 1990) was a British novelist, short-story writer, poet, screenwriter, and wartime fighter ace of Norwegian descent. His books have sold more than 250 million copies worldwide. Dahl has be ...

devotes a chapter to the time he had his adenoids removed without any

anaesthetic An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia ⁠— ⁠in other words, to result in a temporary loss of sensation or awareness. They may be divided into two ...

. This occurred in 1924, when Dahl was eight years old. In

P. G. Wodehouse Sir Pelham Grenville Wodehouse, ( ; 15 October 188114 February 1975) was an English author and one of the most widely read humorists of the 20th century. His creations include the feather-brained Bertie Wooster and his sagacious valet, Jeeve ...

's ''

Right Ho, Jeeves ''Right Ho, Jeeves'' is a novel by P. G. Wodehouse, the second full-length novel featuring the popular characters Jeeves and Bertie Wooster, after ''Thank You, Jeeves''. It was first published in the United Kingdom on 5 October 1934 by Herbert ...

'', Gussie Fink Nottle begins his memorable prize giving speech by explaining that his predecessor in the role was unable to make it because he was dying of adenoids. In

Charlie Chaplin Sir Charles Spencer Chaplin Jr. (16 April 188925 December 1977) was an English comic actor, filmmaker, and composer who rose to fame in the era of silent film. He became a worldwide icon through his screen persona, the Tramp, and is consider ...

's ''

The Great Dictator ''The Great Dictator'' is a 1940 American anti-war political satire black comedy film written, directed, produced, scored by, and starring British comedian Charlie Chaplin, following the tradition of many of his other films. Having been the onl ...

'', the name of the Tomainian Phooey is Adenoid Hynkel. In ''

Gravity's Rainbow ''Gravity's Rainbow'' is a 1973 novel by American writer Thomas Pynchon. The narrative is set primarily in Europe at the end of World War II and centers on the design, production and dispatch of V-2 rockets by the German military. In particular, ...

'', by American novelist

Thomas Pynchon Thomas Ruggles Pynchon Jr. ( , ; born May 8, 1937) is an American novelist noted for his dense and complex novels. His fiction and non-fiction writings encompass a vast array of subject matter, genres and themes, including history, music, scie ...

, Lord Blatherand Osmo is "''assimilated'' by his own growing Adenoid, some horrible transformation of cell plasma it is quite beyond Edwardian medicine to explain". Osmo's travail is remotely experienced by Pirate Prentice, a major character.

References

External links

*
''Adenoids: What They Are, How To Recognize Them, What To Do For Them''

{{Authority control Lymphatics of the head and neck Tonsil Pharynx