Adenoid

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Adenoids
Gray994-adenoid.png
Location of the adenoid
Details
System Lymphatic system
Identifiers
Latin tonsilla pharyngea
MeSH D000234
TA98 A05.3.01.006
TA2 5186
FMA 54970
Anatomical terminology

In anatomy, the pharyngeal tonsil, also known as the nasopharyngeal tonsil or adenoid, is the superior-most of the tonsils. It is a mass of lymphoid tissue located behind the nasal cavity, in the roof and the posterior wall of the nasopharynx, [1] where the nose blends into the throat. In children, it normally forms a soft mound in the roof and back wall of the nasopharynx, just above and behind the uvula.

Contents

The term adenoid is also used to represent adenoid hypertrophy, the abnormal growth of the pharyngeal tonsils. [2]

Structure

The adenoid is a mass of lymphoid tissue located behind the nasal cavity, in the roof and the posterior wall of the nasopharynx, [1] where the nose blends into the throat. The adenoid, unlike the palatine tonsils, has pseudostratified epithelium. [3] The adenoids are part of the so-called Waldeyer ring of lymphoid tissue which also includes the palatine tonsils, the lingual tonsils and the tubal tonsils.

Development

Adenoids develop from a subepithelial infiltration of lymphocytes after the 16th week of embryonic life. After birth, enlargement begins and continues until ages 5 to 7 years.

Function

Part of the immune system, adenoids trap and recognize pathogens such as bacteria and viruses. In response, the adenoid produces T cells and B cells to combat infection, contributing to the synthesis of IgA immunoglobulins, assisting in the body's immunologic memory. [4]

Microbiome

Species of bacteria such as lactobacilli, anaerobic streptococci, actinomycosis, Fusobacterium species, and Nocardia are normally present by 6 months of age. Normal flora found in the adenoid consists of alpha-hemolytic streptococci and enterococci, Corynebacterium species, coagulase-negative staphylococci, Neisseria species, Haemophilus species, Micrococcus species, and Stomatococcus species.[ citation needed ]

Clinical significance

Enlargement

3D still showing adenoid hypertrophy. Adenoid hypertrophy.jpg
3D still showing adenoid hypertrophy.

An enlarged adenoid, or adenoid hypertrophy, can become nearly the size of a ping pong ball 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.[ citation needed ]

Adenoid facies

Enlargement of the adenoid, especially in children, causes an atypical appearance of the face, often referred to as adenoid facies. [5] Features of adenoid facies include mouth breathing, an elongated face, prominent incisors, hypoplastic maxilla, short upper lip, elevated nostrils, and a high arched palate. [6]

Removal

Surgical removal of the adenoid is a procedure called adenoidectomy. Adenoid infection may cause symptoms such as excessive mucus 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. [7] Carried out through the mouth under a general anaesthetic (or less commonly a topical), adenoidectomy involves the adenoid being curetted, cauterized, lasered, or otherwise ablated. The adenoid is often removed along with the palatine tonsils. [8]


See also

Related Research Articles

<span class="mw-page-title-main">Otorhinolaryngology</span> Medical specialty of the head and neck

Otorhinolaryngology is a surgical subspecialty within medicine that deals with the surgical and medical management of conditions of the head and neck. Doctors who specialize in this area are called otorhinolaryngologists, otolaryngologists, head and neck surgeons, or ENT surgeons or physicians. Patients seek treatment from an otorhinolaryngologist for diseases of the ear, nose, throat, base of the skull, head, and neck. These commonly include functional diseases that affect the senses and activities of eating, drinking, speaking, breathing, swallowing, and hearing. In addition, ENT surgery encompasses the surgical management of cancers and benign tumors and reconstruction of the head and neck as well as plastic surgery of the face, scalp, and neck.

<span class="mw-page-title-main">Throat</span> Anterior part of the neck, in front of the vertebra

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), preventing food and drinks being inhaled into the lungs. The throat contains various blood vessels, pharyngeal muscles, the nasopharyngeal tonsil, the tonsils, the palatine uvula, the trachea, the esophagus, and the vocal cords. Mammal throats consist of two bones, the hyoid bone and the clavicle. The "throat" is sometimes thought to be synonymous for the fauces.

<span class="mw-page-title-main">Uvula</span> Fleshy appendage that hangs from the back of the palate

The uvula, also known as the palatine uvula or staphyle, 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 contains many serous glands, which produce thin saliva. It is only found in humans.

<span class="mw-page-title-main">Soft palate</span> Flexible part of maxilla

The soft palate is, in mammals, the soft tissue constituting the back of the roof of the mouth. The soft palate is part of the palate of the mouth; the other part is the hard palate. The soft palate is distinguished from the hard palate at the front of the mouth in that it does not contain bone.

<span class="mw-page-title-main">Palatine tonsil</span> Lymphoid organs at the back of the throat on both sides

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 "white lumps" if they are inflamed or infected with symptoms of exudates and severe swelling.

<span class="mw-page-title-main">Nasal cavity</span> Large, air-filled space above and behind the nose in the middle of the face

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 cavity is the uppermost part of the respiratory system and provides the nasal passage for inhaled air from the nostrils to the nasopharynx and rest of the respiratory tract.

<span class="mw-page-title-main">Adenoidectomy</span> Surgical removal of the adenoid

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 symptoms and/or nasal obstruction has not been well studied. The surgery is less commonly performed in adults in whom the adenoid is much smaller and less active than it is in children. It is most often done on an outpatient basis under general anesthesia. Post-operative pain is generally minimal and reduced by icy or cold foods. The procedure is often combined with tonsillectomy, for which the recovery time is an estimated 10–14 days, sometimes longer, mostly dependent on age.

<span class="mw-page-title-main">Lingual tonsils</span> Lymphatic tissue in the tongue

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 the immune response when the lingual tonsils get in contact with invading microorganisms.

<span class="mw-page-title-main">Nasal congestion</span> Partial or complete blockage of nasal passages

Nasal congestion is the partial or complete blockage of nasal passages, leading to impaired nasal breathing, usually due to membranes lining the nose becoming swollen from inflammation of blood vessels.

The mucosa-associated lymphoid tissue (MALT), also called mucosa-associated lymphatic tissue, is a diffuse system of small concentrations of lymphoid tissue found in various submucosal membrane sites of the body, such as the gastrointestinal tract, nasopharynx, thyroid, breast, lung, salivary glands, eye, and skin. MALT is populated by lymphocytes such as T cells and B cells, as well as plasma cells, dendritic cells and macrophages, each of which is well situated to encounter antigens passing through the mucosal epithelium. In the case of intestinal MALT, M cells are also present, which sample antigen from the lumen and deliver it to the lymphoid tissue. MALT constitute about 50% of the lymphoid tissue in human body. Immune responses that occur at mucous membranes are studied by mucosal immunology.

<span class="mw-page-title-main">Head and neck anatomy</span> Structure of the human head and neck

This article describes the anatomy of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat.

<span class="mw-page-title-main">Waldeyer's tonsillar ring</span> A ringed arrangement of lymphoid tissue in the pharynx

Waldeyer's tonsillar ring is a ringed arrangement of lymphoid organs in the pharynx. Waldeyer's ring surrounds the naso- and oropharynx, with some of its tonsillar tissue located above and some below the soft palate.

<span class="mw-page-title-main">Tonsil</span> Lymphoid organs in the mouth and throat

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 an important role in the immune system.

<span class="mw-page-title-main">Adenoid hypertrophy</span> Enlargement of the adenoid tonsil

Adenoid hypertrophy, also known as enlarged adenoids refers to an enlargement of the adenoid that is linked to nasopharyngeal mechanical blockage and/or chronic inflammation. Adenoid hypertrophy is a characterized by hearing loss, recurrent otitis media, mucopurulent rhinorrhea, chronic mouth breathing, nasal airway obstruction, increased infection susceptibility, and dental malposition.

Velopharyngeal insufficiency is a disorder of structure that causes a failure of the velum to close against the posterior pharyngeal wall during speech in order to close off the nasal cavity during oral speech production. This is important because speech requires sound from the vocal folds and airflow from the lungs to be directed into the oral cavity (mouth) for the production of all speech sounds, with the exception of nasal consonants. If complete closure does not occur during speech, this can cause hypernasality and/or audible nasal emission during speech. In addition, there may be inadequate airflow to produce most consonants, making them sound weak or omitted.

<span class="mw-page-title-main">Human nose</span> Feature of the human face

The human nose is the first organ of the respiratory system. It is also the principal organ in the olfactory system. The shape of the nose is determined by the nasal bones and the nasal cartilages, including the nasal septum, which separates the nostrils and divides the nasal cavity into two.

<span class="mw-page-title-main">Adenoiditis</span> Medical condition

Adenoiditis is the inflammation of the adenoid tissue usually caused by an infection. Adenoiditis is treated using medication or surgical intervention.

<span class="mw-page-title-main">Wilhelm Meyer (physician)</span>

The Danish physician Wilhelm Meyer (1824–1895) was the first to describe the clinical condition of nasal obstruction with chronic mouth breathing, snoring, dull facial expression, and hearing impairment due to adenoid hypertrophy.

<span class="mw-page-title-main">Pharynx</span> Part of the throat that is behind the mouth and nasal cavity

The pharynx is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea. It is found in vertebrates and invertebrates, though its structure varies across species. The pharynx carries food to the esophagus and air to the larynx. The flap of cartilage called the epiglottis stops food from entering the larynx.

<span class="mw-page-title-main">Tonsillar crypts</span> Deep indentations in human tonsils

The human palatine tonsils (PT) are covered by stratified squamous epithelium that extends into deep and partly branched tonsillar crypts, of which there are about 10 to 30. The crypts greatly increase the contact surface between environmental influences and lymphoid tissue. In an average adult palatine tonsil the estimated epithelial surface area of the crypts is 295 cm2, in addition to the 45 cm2 of epithelium covering the oropharyngeal surface.

References

  1. 1 2 Standring, Susan; Gray, Henry, eds. (2021). Gray's anatomy: the anatomical basis of clinical practice (42nd ed.). Amsterdam: Elsevier. p. 703. ISBN   978-0-7020-7705-0. OCLC   1202943188.
  2. "Definition of ADENOID". www.merriam-webster.com. Retrieved 2018-05-05.
  3. Histology at KUMC lymphoid-lymph06
  4. Mnatsakanian, A.; Heil, J. R.; Sharma, S. (2023). "Anatomy, Head and Neck: Adenoids". National Library of Medicine. PMID   30844164 . Retrieved 2 June 2023.
  5. Jefferson, Yosh (2017-02-01). "Mouth breathing: adverse effects on facial growth, health, academics, and behavior". General Dentistry. 58 (1): 18–25, quiz 26–27, 79–80. ISSN   0363-6771. PMID   20129889.
  6. Wahba, Mohammed. "Adenoid facies". Radiopaedia.org. Radiology Reference Article. Retrieved 2016-11-06.
  7. Lesinskas, Eugenijus; Drigotas, Martynas (2009-04-01). "The incidence of adenoidal regrowth after adenoidectomy and its effect on persistent nasal symptoms". European Archives of Oto-Rhino-Laryngology. 266 (4): 469–473. doi:10.1007/s00405-008-0892-5. ISSN   1434-4726. PMID   19093130. S2CID   31941117.
  8. "Adenoids". MedlinePlus, US National Library of Medicine. 13 September 2022. Retrieved 23 July 2023.