Theadenoid, also known as thepharyngeal tonsil, ornasopharyngeal tonsil is thesuperior-most of thetonsils. It is a mass oflymphoid tissue located behind thenasal cavity, in the roof and the posterior wall of thenasopharynx,[1] where thenose blends into thethroat. Inchildren, it normally forms a soft mound in the roof and back wall of the nasopharynx, just above and behind theuvula.
The termadenoid is also used inanatomy to representadenoid hypertrophy, the abnormal growth of the pharyngeal tonsils.[2]
Adenoids develop from a subepithelial infiltration oflymphocytes after the 16th week of embryonic life. After birth, enlargement begins and continues until the ages of 5 to 7 years.
The adenoids are a part of theimmune system that recognizes and traps pathogens such as bacteria and viruses. In response, the adenoid producesT cells andB cells to combat infection, contributing to the synthesis of IgAimmunoglobulins, assisting in the body's immunologic memory.[4]
An enlarged adenoid, oradenoid hypertrophy, can become nearly the size of aping 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 stopping nasal airflow.
Symptomatic enlargement between 18 and 24 months of age is not uncommon, meaning thatsnoring, nasal airway obstruction, and obstructed breathing may occur during sleep. Adenoid growth typically stops between ages five and seven, and therefore adenoid hypertrophy often regresses naturally in children around ages seven to eight.[7]
Adenoid facies is an atypical appearance of the face caused by enlargement of the adenoid, found especially in children.[8] Features of adenoid facies includemouth breathing, an elongated face, prominent incisors,hypoplasticmaxilla, short upper lip, elevated nostrils, and a high arched palate.[9]
Surgical removal of the adenoid is throughadenoidectomy. Adenoid infection may cause symptoms such as excessivemucus production. Removing the adenoid treats this symptom. Studies have shown that adenoid regrowth occurs in up to 19% of cases after removal.[10] Carried out through the mouth under ageneral anaesthetic (or less commonly atopical), adenoidectomy involves the adenoid beingcuretted,cauterized,lasered, or otherwiseablated. The adenoid is often removed along with thepalatine tonsils.[11]
^Johnston, James Jordan and Richard Douglas. 2018. "Adenotonsillar Microbiome: An Update." Postgraduate Medical Journal 94 (1113) (07): 398.
^Darrow, David H., and Nathan A. Kludt. "Adenotonsillar Disease." In Pediatric Otolaryngology for the Clinician, pp. 187-195. Totowa, NJ: Humana Press, 2009.
^Palazzo, Giuseppe, Rosalia Leonardi, Gaetano Isola, Manuel Lagravere, and Antonino Lo Giudice. 2025. "Changes in Upper Airway Airflow After Rapid Maxillary Expansion Beyond the Peak Period of Adenoidal Growth—A CBCT Study Using Computer Fluid Dynamics and Considering Adenoidal Dimensions as a Factor" Dentistry Journal 13, no. 5: 209.https://doi.org/10.3390/dj13050209
^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.ISSN0363-6771.PMID20129889.
^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.ISSN1434-4726.PMID19093130.S2CID31941117.
^"Adenoids". MedlinePlus, US National Library of Medicine. 13 September 2022. Retrieved23 July 2023.
