Appendix ( anatomy ) - wikipedia Appendix ( anatomy ) For other uses, see Appendix ( disambiguation ). Appendix Drawing of colon with variability of appendix as seen from front Arteries of cecum and appendix ( appendix labeled as vermiform process at lower right ) Details Precursor Midgut System Digestive system Artery Appendicular artery Vein Appendicular vein Identifiers Latin Appendix vermiformis MeSH A03. 556.124. 526.209. 290 Dorlands / Elsevier Vermiform appendix TA A05. 7.02. 007 FMA 14542 Anatomical terminology ( edit on Wikidata ) Ileocecal junction ( Appendix appear in blue color ) The appendix ( or vermiform appendix ; also cecal ( or caecal ) appendix ; vermix ; or vermiform process ) is a blind - ended tube connected to the cecum, from which it develops in the embryo. The cecum is a pouchlike structure of the colon, located at the junction of the small and the large intestines. The term `` vermiform '' comes from Latin and means `` worm - shaped ''. Contents 1 Structure 1.1 Variation 2 Functions 2.1 Maintaining gut flora 2.2 Immune and lymphatic system 2.3 Vestigiality 3 Clinical significance 3.1 Appendicitis 3.2 Surgery 4 History 5 Additional images 6 See also 7 References 8 Further reading Structure The human appendix averages 9 cm in length but can range from 2 to 20 cm. The diameter of the appendix is usually between 7 and 8 mm. The longest appendix ever removed was 26 cm long. It was removed from a patient in Zagreb, Croatia. The appendix is usually located in the lower right quadrant of the abdomen, near the right hip bone. The base of the appendix is located 2 cm beneath the ileocecal valve that separates the large intestine from the small intestine. Its position within the abdomen corresponds to a point on the surface known as McBurney 's point. The appendix is connected to the mesentery in the lower region of the ileum, by a short region of the mesocolon known as the mesoappendix. Variation Some identical twins -- known as mirror image twins -- can have a mirror - imaged anatomy, a congenital condition with the appendix located in the lower left quadrant of the abdomen. Intestinal malrotation may also cause displacement of the appendix to the left side. While the base of the appendix is at a fairly constant location -- 2 cm below the ileocecal valve, the tip of the appendix can be variably located -- in the pelvis, outside the peritoneum or behind the cecum. The prevalence of the different positions varies amongst populations with the retrocecal position being most common in Ghana and Sudan, with 67.3 % and 58.3 % occurrence respectively, in comparison to Iran and Bosnia where the pelvic position is most common, with 55.8 % and 57.7 % occurrence respectively. In very rare cases ( laparotomies for suspected appendicitis have given a frequency of 1 in 100,000 ), the appendix may not be present at all. Sometimes there is a semi-circular fold of mucous membrane at the opening of the appendix. This valve of the vermiform appendix is also called Gerlach 's valve. Functions Maintaining gut flora A possible function of the human appendix is a `` safe house '' for beneficial bacteria in the recovery from diarrhea. Although it has been long accepted that the immune tissue surrounding the appendix and elsewhere in the gut -- called gut associated lymphoid tissue -- carries out a number of important functions, explanations were lacking for the distinctive shape of the appendix and its apparent lack of specific importance and function as judged by an absence of side effects following its removal. Therefore, the notion that the appendix is only vestigial became widely held. William Parker, Randy Bollinger, and colleagues at Duke University proposed in 2007 that the appendix serves as a haven for useful bacteria when illness flushes those bacteria from the rest of the intestines. This proposal is based on an understanding that emerged by the early 2000s of how the immune system supports the growth of beneficial intestinal bacteria, in combination with many well - known features of the appendix, including its architecture, its location just below the normal one - way flow of food and germs in the large intestine, and its association with copious amounts of immune tissue. Research performed at Winthrop -- University Hospital showed that individuals without an appendix were four times more likely to have a recurrence of Clostridium difficile colitis. The appendix, therefore, may act as a safe house for good bacteria. This reservoir of bacteria could then serve to repopulate the gut flora in the digestive system following a bout of dysentery or cholera, or boost it following a milder gastrointestinal illness. Immune and lymphatic system The appendix has been identified as an important component of mammalian mucosal immune function, particularly B cell mediated immune responses and extrathymically derived T cells. This structure helps in the proper movement and removal of waste matter in the digestive system, contains lymphatic vessels that regulate pathogens, and lastly, might even produce early defences that prevent deadly diseases. Additionally, it is thought that this may provide more immune defences from invading pathogens and getting the lymphatic system 's B and T cells to fight the viruses and bacteria that infect that portion of the bowel and training them, so that immune responses are targeted and more able to reliably and less dangerously fight off pathogens. In addition there are different immune cells called innate lymphoid cells that function in the gut, to help the appendix maintain digestive health. Vestigiality The human appendix had been proposed to be a vestigial structure, a structure that has lost all or most of its original function, or that has evolved to take on a new function. The suggestion was that it is the shrunken remnant of the cecum thought to have been present in a remote ancestor of humans. This notion is still widely held. A 2013 study, however, refutes the idea of an inverse relationship between cecum size and appendix size and presence. Ceca, which occur in the digestive tracts of many herbivores ( e.g. ox, horse ), house mutualistic bacteria and ingested small stones that help animals digest the cellulose molecules found in plants. It is widely present in euarchontoglires ( a superorder of mammals that includes rodents and primates ) and has also evolved independently in the diprotodont marsupials, monotremes, and is highly diverse in size and shape. A possible scenario for the progression from a fully functional cecum to the current human appendix was put forth by Charles Darwin. He suggested that the appendix was used for digesting leaves as primates. It may be a vestigial organ of ancient humans that has degraded to nearly nothing of its original purpose, or evolved to take on a new purpose over the course of evolution. The very long cecum of some herbivorous animals, such as found in the horse or the koala, appears to support this theory. The koala 's cecum enables it to host bacteria that specifically help to break down cellulose. Human ancestors may have also relied upon this system when they lived on a diet rich in foliage. As people began to eat more easily digested foods, they may have become less reliant on cellulose - rich plants for energy. As the cecum became less necessary for digestion, mutations that were previously deleterious ( and would have hindered evolutionary progress ) were no longer important, so the mutations survived. It is suggested that these alleles became more frequent and the cecum continued to shrink. After millions of years, the once - necessary cecum degraded to be the appendix of modern humans. Clinical significance An appendiceal carcinoid tumor The most common diseases of the appendix ( in humans ) are appendicitis and carcinoid tumors ( appendiceal carcinoid ). Appendix cancer accounts for about 1 in 200 of all gastrointestinal malignancies. In rare cases, adenomas are also present. Appendicitis Main article : Appendicitis Appendicitis is a condition characterized by inflammation of the appendix. Pain often begins in the center of the abdomen, corresponding to the appendix 's development as part of the embryonic midgut. This pain is typically a dull, poorly localized, visceral pain. As the inflammation progresses, the pain begins to localize more clearly to the right lower quadrant, as the peritoneum becomes inflamed. This peritoneal inflammation, or peritonitis, results in rebound tenderness ( pain upon removal of pressure rather than application of pressure ). In particular, it presents at McBurney 's point, 1 / 3 of the way along a line drawn from the anterior superior iliac spine to the umbilicus. Typically, point ( skin ) pain is not present until the parietal peritoneum is inflamed, as well. Fever and an immune system response are also characteristic of appendicitis. Appendicitis usually requires the removal of the inflamed appendix, in an appendectomy either by laparotomy or laparoscopy. Untreated, the appendix may rupture, leading to peritonitis, followed by shock, and, if still untreated, death. Surgery Main article : Appendectomy The surgical removal of the appendix is called an appendectomy. This removal is normally performed as an emergency procedure when the patient is suffering from acute appendicitis. In the absence of surgical facilities, intravenous antibiotics are used to delay or avoid the onset of sepsis. In some cases, the appendicitis resolves completely ; more often, an inflammatory mass forms around the appendix. This is a relative contraindication to surgery. The appendix is also used for the construction of an efferent urinary conduit, in an operation known as the Mitrofanoff procedure, in people with a neurogenic bladder. The appendix is also used as a means to access the colon in children with paralysed bowels or major rectal sphincter problems. The appendix is brought out to the skin surface and the child / parent can then attach a catheter and easily wash out the colon ( via normal defaecation ) using an appropriate solution. History Dr. Heather F. Smith of Midwestern University and colleagues explained : Recently... improved understanding of gut immunity has merged with current thinking in biological and medical science, pointing to an apparent function of the mammalian cecal appendix as a safe - house for symbiotic gut microbes, preserving the flora during times of gastrointestinal infection in societies without modern medicine. This function is potentially a selective force for the evolution and maintenance of the appendix. Three morphotypes of cecal - appendices can be described among mammals based primarily on the shape of the cecum : a distinct appendix branching from a rounded or sac - like cecum ( as in many primate species ), an appendix located at the apex of a long and voluminous cecum ( as in the rabbit, greater glider and Cape dune mole rat ), and an appendix in the absence of a pronounced cecum ( as in the wombat ). In addition, long narrow appendix - like structures are found in mammals that either lack an apparent cecum ( as in monotremes ) or lack a distinct junction between the cecum and appendix - like structure ( as in the koala ). A cecal appendix has evolved independently at least twice, and apparently represents yet another example of convergence in morphology between Australian marsupials and placentals in the rest of the world. Although the appendix has apparently been lost by numerous species, it has also been maintained for more than 80 million years in at least one clade. In a more recent paper, the appendix was found to have evolved at least 32 times ( and perhaps as many as 38 times ) and to have been lost no more than six times. This suggests that the cecal appendix has a selective advantage in many situations and argues strongly against its vestigial nature. This complex evolutionary history of the appendix, along with a great heterogeneity in its evolutionary rate in various taxa, suggests that it is a recurrent trait. Such a function may be useful in a culture lacking modern sanitation and healthcare practice, where diarrhea may be prevalent. Current epidemiological data on the cause of death in developed countries collected by the World Health Organization in 2001 show that acute diarrhea is now the fourth leading cause of disease - related death in developing countries ( data summarized by The Bill and Melinda Gates Foundation ). Two of the other leading causes of death are expected to have exerted limited or no selection pressure. Additional images Illustration depicting the location of the appendix in a child Normal location of the appendix relative to other organs of the digestive system ( frontal view ) Vermiform appendix Ileo - cecal valve and vermiform appendix Mucinous adenocarcinoma of the appendix tip Cross section of the appendix with Enterobius with H&E stain Histology of vermiform appendix See also Meckel 's diverticulum References Jump up ^ `` Largest appendix removed ''. Guinness World Records. Retrieved 22 May 2017. ^ Jump up to : Golalipour, M.J. ; Arya, B. ; Jahanshahi, M. ; Azarhoosh, R. ( 2003 ). `` Anatomical Variations Of Vermiform Appendix In South - East Caspian Sea ( Gorgan - IRAN ) '' ( PDF ). J. Anat. Soc. India. Retrieved 1 October 2014. Jump up ^ `` Unusual Types of Twins ''. Multiples of America. Retrieved 30 April 2014. Jump up ^ Gedda L, Sciacca A, Brenci G, et al. ( 1984 ). `` Situs viscerum specularis in monozygotic twins ''. Acta Genet Med Gemellol ( Roma ). 33 ( 1 ) : 81 -- 5. PMID 6540028. Jump up ^ O Ngim ; L Adams ; A Achaka ; O Busari ; O Rahaman ; I Ukpabio ; D Eduwem. ( 2013 ). `` Left - Sided Acute Appendicitis With Situs Inversus Totalis In A Nigerian Male -- A Case Report And Review Of Literature. ''. The Internet Journal of Surgery. 30 ( 4 ). Jump up ^ Paterson - Brown, S. ( 2007 ). `` 15. The acute abdomen and intestinal obstruction ''. In Parks, Rowan W. ; Garden, O. James ; Carter, David John ; Bradbury, Andrew W. ; Forsythe, John L.R. Principles and practice of surgery ( 5th ed. ). Edinburgh : Churchill Livingstone. ISBN 0 - 443 - 10157 - 4. Jump up ^ Clegg - Lamptey JN, Armah H, Naaeder SB, Adu - Aryee NA ( 2006 ). `` Position and susceptibility to inflammation of vermiform appendix in Accra, Ghana ''. East Afr Med J. 83 ( 12 ) : 670 -- 3. PMID 17685212. Jump up ^ Bakheit MA, Warille AA ( 1999 ). `` Anomalies of the vermiform appendix and prevalence of acute appendicitis in Khartoum ''. East Afr Med J. 76 ( 6 ) : 338 -- 40. PMID 10750522. Jump up ^ Ghorbani A, Forouzesh M, Kazemifar AM ( 2014 ). `` Variation in Anatomical Position of Vermiform Appendix among Iranian Population : An Old Issue Which Has Not Lost Its Importance ''. Anat Res Int. 2014 : 313575. PMC 4176911. PMID 25295193. doi : 10.1155 / 2014 / 313575. Jump up ^ Denjalić A, Delić J, Delić - Custendil S, Muminagić S ( 2009 ). `` ( Variations in position and place of formation of appendix vermiformis found in the course of open appendectomy ) ''. Med Arh ( in Bosnian ). 63 ( 2 ) : 100 -- 1. PMID 19537667. Jump up ^ Zetina - Mejía CA, Alvarez - Cosío JE, Quillo - Olvera J ( 2009 ). `` Congenital absence of the cecal appendix. Case report ''. Cir Cir. 77 ( 5 ) : 407 -- 10. PMID 19944032. Jump up ^ Kumar, Vinay ; Robbins, Stanley L. ; Cotran, Ramzi S. ( 1989 ). Robbins ' pathologic basis of disease ( 4th ed. ). Philadelphia : Saunders. pp. 902 -- 3. ISBN 0 - 7216 - 2302 - 6. ^ Jump up to : Associated Press. `` Scientists may have found appendix 's purpose ''. MSNBC, 5 October 2007. Accessed 17 March 2009. ^ Jump up to : Bollinger, R.R. ; Barbas, A.S. ; Bush, E.L. ; Lin, S.S. ; Parker, W. ( 21 December 2007 ). `` Biofilms in the large bowel suggest an apparent function of the human vermiform appendix ''. Journal of Theoretical Biology. 249 ( 4 ) : 826 -- 831. ISSN 0022 - 5193. PMID 17936308. doi : 10.1016 / j. jtbi. 2007.08. 032. Jump up ^ Sonnenburg J.L. ; Angenent L.T. ; Gordon J.I. ( June 2004 ). `` Getting a grip on things : how do communities of bacterial symbionts become established in our intestine ? ''. Nat. Immunol. 5 ( 6 ) : 569 -- 73. PMID 15164016. doi : 10.1038 / ni1079. Jump up ^ Everett M.L. ; Palestrant D. ; Miller S.E. ; Bollinger R.R. ; Parker W. ( 2004 ). `` Immune exclusion and immune inclusion : a new model of host - bacterial interactions in the gut ''. Clinical and Applied Immunology Reviews. 5 ( 5 ) : 321 -- 32. doi : 10.1016 / j. cair. 2004.03. 001. Jump up ^ Dunn, Rob. `` Your Appendix Could Save Your Life ''. Retrieved 22 December 2016. Jump up ^ Zahid, Aliya ( 2004 - 04 - 01 ). `` The vermiform appendix : not a useless organ ''. Journal of the College of Physicians and Surgeons -- Pakistan : JCPSP. 14 ( 4 ) : 256 -- 258. ISSN 1022 - 386X. PMID 15228837. Jump up ^ Rankin, Lucille C. ; Girard - Madoux, Mathilde J.H. ; Seillet, Cyril ; Mielke, Lisa A. ; Kerdiles, Yann ; Fenis, Aurore ; Wieduwild, Elisabeth ; Putoczki, Tracy ; Mondot, Stanislas ( 2016 - 02 - 01 ). `` Complementarity and redundancy of IL - 22 - producing innate lymphoid cells ''. Nature Immunology. 17 ( 2 ) : 179 -- 186. ISSN 1529 - 2908. PMC 4720992. PMID 26595889. doi : 10.1038 / ni. 3332. Jump up ^ Research, The Walter and Eliza Hall Institute of Medical ( 2016 - 08 - 19 ). `` Lucille Rankin ''. Walter and Eliza Hall Institute of Medical Research. Retrieved 2016 - 11 - 02. ^ Jump up to : Smith H.F. ; Parker W. ; Kotzé, S.H. ; Laurin, M. ( 2013 ). `` Multiple independent appearances of the cecal appendix in mammalian evolution and an investigation of related ecological and anatomical factors ''. Comptes rendus Palevol. doi : 10.1016 / j. crpv. 2012.12. 001. Jump up ^ `` Animal Structure & Function ''. Sci.waikato.ac.nz. Retrieved 2011 - 10 - 03. ^ Jump up to : Smith H.F. ; Fisher R.E. ; Everett M.L. ; Thomas A.D. ; Bollinger, R.R. ; Parker W. ( 2009 ). `` Comparative anatomy and phylogenetic distribution of the mammalian cecal appendix ''. Journal of Evolutionary Biology. 22 ( 10 ) : 1984 -- 1999. PMID 19678866. doi : 10.1111 / j. 1420 - 9101.2009. 01809. x. Jump up ^ Darwin, Charles ( 1871 ) `` Jim 's Jesus ''. The Descent of Man, and Selection in Relation to Sex. John Murray : London. Jump up ^ `` Appendix disorders Symptoms, Diagnosis, Treatments and Causes ''. Wrongdiagnosis.com. Retrieved 2010 - 05 - 19. Jump up ^ `` Statistics about Appendix disorder ''. Wrongdiagnosis.com. Retrieved 2010 - 05 - 19. ^ Jump up to : Miller R., Kenneth ; Levine, Joseph ( 2002 ). Biology. Prentice Hall. pp. 92 -- 98. ISBN 0 - 13 - 050730 - X. Jump up ^ Mingin G.C. ; Baskin L.S. ( 2003 ). `` Surgical management of the neurogenic bladder and bowel ''. Int Braz J Urol. 29 ( 1 ) : 53 -- 61. PMID 15745470. doi : 10.1590 / S1677 - 55382003000100012. Jump up ^ `` Wellington Children 's Hospital : Caring for an ACE or Chait Tube : Healthpoint ''. Retrieved 22 December 2016. Jump up ^ Laurin M. ; Everett, M.L. ; Parker W. ( 2011 ). `` The cecal appendix : one more immune component with a function disturbed by post-industrial culture ''. Anatomical Record. 294 ( 4 ) : 567 -- 579. doi : 10.1002 / ar. 21357. Jump up ^ Needs Citation Jump up ^ Evolution of the Appendix : A Biological ' Remenant ' No More ; By Duke Medicine News and Communications ; Published : 20 August 2009 Updated : 21 August 2009, http://www.dukehealth.org/health_library/news/evolution_of_the_appendix_a_biological_remnant_no_more Further reading Wikimedia Commons has media related to Appendix ( anatomy ). Appendix May Actually Have a Purpose -- 2007 WebMD article Anatomy photo : 37 : 12 - 0102 at the SUNY Downstate Medical Center -- `` Abdominal Cavity : The Cecum and the Vermiform Appendix '' `` The vestigiality of the human vermiform appendix : A Modern Reappraisal '' -- evolutionary biology argument that the appendix is vestigial Smith, H.F. ; Fisher, R.E. ; Everett, M.L. ; Thomas, A.D. ; Bollinger, R. Randal ; Parker, W. ( October 2009 ). `` Comparative anatomy and phylogenetic distribution of the mammalian cecal appendix ''. Journal of Evolutionary Biology. 22 ( 10 ) : 1984 -- 99. ISSN 1420 - 9101. PMID 19678866. doi : 10.1111 / j. 1420 - 9101.2009. 01809. x. Cho, Jinny. `` Scientists refute Darwin 's theory on appendix ''. The Chronicle ( Duke University ), August 27, 2009. ( News article on the above journal article. ) Anatomy of the gastrointestinal tract, excluding the mouth Upper Pharynx Muscles Spaces peripharyngeal retropharyngeal parapharyngeal retrovisceral danger prevertebral Pterygomandibular raphe Pharyngeal raphe Buccopharyngeal fascia Pharyngobasilar fascia Piriform sinus Esophagus Sphincters upper lower glands Stomach Curvatures greater lesser Angular incisure Cardia Body Fundus Pylorus antrum canal sphincter Gastric mucosa Gastric folds Microanatomy Gastric pits Gastric glands Cardiac glands Fundic glands Pyloric glands Foveolar cell Parietal cell Gastric chief cell Enterochromaffin - like cell Lower Small intestine Microanatomy Intestinal villus Intestinal gland Enterocyte Enteroendocrine cell Goblet cell Paneth cell Duodenum Suspensory muscle Major duodenal papilla Minor duodenal papilla Duodenojejunal flexure Brunner 's glands Jejunum No substructures Ileum Ileocecal valve Peyer 's patches Microfold cell Large intestine Cecum Appendix Colon Ascending colon Hepatic flexure Transverse colon Splenic flexure Descending colon Sigmoid colon Continuous taenia coli haustra epiploic appendix Rectum Transverse folds Ampulla Anal canal Anus Anal columns Anal valves Anal sinuses Pectinate line Internal anal sphincter Intersphincteric groove External anal sphincter Wall Serosa / Adventitia Subserosa Muscular layer Submucosa Circular folds Mucosa Muscularis mucosa Retrieved from `` https://en.wikipedia.org/w/index.php?title=Appendix_(anatomy)&oldid=798362567 '' Categories : Digestive system Vestigial organs Hidden categories : All articles with dead external links Articles with dead external links from July 2017 Articles with permanently dead external links CS1 Bosnian - language sources ( bs ) Medicine infobox template using GraySubject or GrayPage Medicine infobox template using Dorlands parameter Talk Contents About Wikipedia Afrikaans বাংলা Български Bosanski Català Čeština Cymraeg Deutsch ދިވެހިބަސް Eesti Ελληνικά Español Esperanto Euskara فارسی Français Gaeilge Galego 客家 語 / Hak - kâ - ngî 한국어 Հայերեն Hrvatski Bahasa Indonesia Italiano עברית Basa Jawa Kapampangan Kurdî Latviešu Lietuvių Limburgs Magyar മലയാളം मराठी Bahasa Melayu Nederlands नेपाली 日本 語 Oʻzbekcha / ўзбекча Polski Português Română Русский Simple English Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Suomi Tagalog தமிழ் తెలుగు ไทย Türkçe Українська ئۇيغۇرچە / Uyghurche Tiếng Việt 粵語 中文 Edit links This page was last edited on 1 September 2017, at 13 : 22. 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Question: where is the appendix in the human body located
Answer: at the junction of the small and the large intestines