appendix

1. 1. An appendage.
   2. A collection of supplementary material, usually at the end of a book.
2. The vermiform appendix.
3. Anatomy. A supplementary or accessory part of a bodily organ or structure.

[Latin, from appendere, to hang upon. See append.]

For more information on appendix, visit Britannica.com.

A narrow, elongated tube closed at one end, extending from the cecum, a blind pocket off the first part of the large intestine. It is found in only a few mammals. The size and detailed structure of the appendix vary markedly, depending on the species and the age of the individual. Most reptiles, birds, and mammals have a single or a paired cecum at the anterior end of the large intestine, but it is quite rare that this cecum has a thinner projection or true appendix.

In humans the appendix is about 3 in. (7.5 cm) long, but it varies greatly in both size and its specific location in the lower right quarter of the abdomen. The exact function of the human appendix is unknown, and it is considered to be a remnant of a portion of the digestive tract which was once more functional and is now in the process of evolutionary regression. The appendixes presumably function in digestion in forms with larger ones.

The appendix is more correctly known as the ‘vermiform appendix’, meaning worm-like. It is present only in man, certain anthropoid apes, and the wombat (a nocturnal, burrowing Australian marsupial). Many herbivores are provided with a comparable, but larger structure, in which bacterial breakdown of cellulose, the main constituent of cell walls in plant fibre, takes place. In man the appendix is thought to represent a vestigial organ — one that remains in diminished form after it has ceased, in evolutionary terms, to have any significant function.

The appendix is a short, blind-ended tube arising from the caecum, the first part of the large intestine, within the lower right part of the abdominal cavity. In about half the population, the appendix is ‘retrocaecal’ — behind the caecum; in most cases, it is mobile within the abdominal cavity, suspended from the rest of the bowel by a sling-like fold of tissue (a mesentery), which has the artery to the appendix running in its free edge. The appendix first appears in the fetus at about 6 weeks of development, being initially high up in the abdomen but later descending to its final position. Approximately 1 in 100 000 people are born without an appendix — and very rarely there are two. The appendix is typically 6-9 cm long, but the length varies considerably, from 2 to 30 cm; on average it is 0.5 cm longer in the male than in the female. It is longer in the child than in the adult and shrinks further after mid life. The internal diameter of the appendix is described as wide enough to admit a matchstick, but this lumen may be partially or completely obliterated after middle age. The structure of the tube is basically the same as that of the large intestine: it has an outer muscular coat lined by a much-folded lining (mucosa). It also has aggregates of lymphoid tissue within its walls, which may replace the muscle coat in places.

The appendix in man is medically important because of its propensity to become inflamed in the condition known as acute appendicitis. In this condition, the appendix becomes swollen and the wall fills with inflammatory cells. The process may be initiated by blockage with material from the bowel. If this inflammatory process is allowed to continue, the appendix will become gangrenous and perforate, leading to peritonitis. Acute appendicitis is the most common cause of intra-abdominal infection in developed countries and appendicectomy is the most commonly performed emergency surgical operation. It is less common in developing countries where the diet contains significantly more fibre than our own. In the UK, 1.9 females and 1.5 males per thousand of the population each year get acute appendicitis and have their appendix removed. At the current rate, one in every 6 or 7 people will eventually undergo appendicectomy, even though the incidence of acute appendicitis in the UK has decreased by 50% since the 1970s. The mortality from acute appendicitis has also fallen dramatically, due to a number of factors including better general nutrition, earlier presentation to hospital, and improved anaesthetics. Post- operative problems, such as wound infection, have also become rarer due to the widespread use of antibiotics before surgery. Although appendicitis can occur at any age, it is commonest between 8 and 14 years. It is rare in the elderly and in infants below the age of 2. The cardinal sign of appendicitis is abdominal pain, which is often rather vague and poorly localized initially. As the inflammatory process proceeds, however, the pain usually localizes to the right side of the lower abdomen over the site of the appendix. There is tenderness over the appendix, often accompanied by a slight fever, a facial flush, and a rapid pulse. Despite this apparently typical picture the diagnosis is often difficult to make, particularly in females in whom gynaecological problems are also common and may closely mimic appendicitis. A percentage of appendices removed prove to be normal when examined under the microscope.

The first record of what may have been appendicitis was made by Aretaios around the third century ad. Though the appendix appeared in the anatomical drawings of Leonardo da Vinci from 1492, it was not until 1521 that it was described by an Italian anatomist, Berengario da Carpi. While there is some debate as to who first removed an appendix in England, the first deliberate appendicectomy for acute appendicitis was undertaken by a gynaecologist, Robert Lawson Tait, in May 1880 in Birmingham. The patient recovered. Prior to this Claudius Amyand, physician to Queen Anne, in 1736 successfully removed an acutely inflamed appendix from inside the hernial sac of a young boy.

— A. Winter, P. J. O'Dwyer

Bibliography

• Knut, H., (ed.) (1989). The illustrated history of surgery. Harold Starke, London

See also alimentary system.

A residual part of the intestinal tract, a small sac-like process extending from the caecum, some 4-8 cm long. Acute inflammation, caused by an obstruction (appendicitis) can lead to perforation and peritonitis if surgery is not performed in time. See also gastro-intestinal tract.

The appendix is a worm-shaped extension of the large intestine. It forms the blind end of the caecum, a pouch at the junction between the small and large intestine.

The appendix is believed to have had an important function in mammalian ancestors of humans, harbouring beneficial bacteria that enabled their hosts to break down the cellulose of plants. The human appendix has lost this function and has diminished in size during its evolution. It is therefore regarded as a vestigial, non-essential organ. One in 100 000 people has no appendix and its absence appears to do no harm.

Despite its lack of function, the appendix is relatively easily infected with bacteria. The infection may cause appendicitis, an acute inflammation causing persistent pain in the lower right abdomen, made worse by pressure, coughing, sneezing, or even slight movements. Nausea is another common symptom. Appendicitis is the commonest reason for emergency abdominal surgery. In Britain, more than 80 000 people who experience these symptoms have their appendix removed surgically. Appendicitis develops suddenly and is potentially very dangerous because the appendix may burst, spreading the infection into the surrounding membranes and causing peritonitis which can be fatal if not treated. Unfortunately, diagnosis is difficult and many of the appendices removed (up to 30 per cent in a recent Swedish study) are found to be healthy. Diagnosis becomes easier as the inflammation develops, but delay in removal increases the danger of an appendix bursting.

Fit people who have undergone surgery for uncomplicated appendicitis can usually return to training within a few weeks of the operation, but should not indulge in very vigorous exercise until a few weeks after that.

An accessory part of a main structure; in human anatomy, generally refers to the vermiform appendix, which is located at the junction of the small and large intestines.

A small saclike organ located at the upper end of the large intestine. The appendix has no known function in present-day humans, but it may have played a role in the digestive system in humans of earlier times. The appendix is also called the vermiform appendix because of its wormlike (“vermiform”) shape.

Pl. appendices [L.]
1. a slender outgrowth or appendage.
2. the vermiform appendix, a slender diverticulum present in only a few mammals such as the rabbit, humans and the great apes. A structure of doubtful function, rich in lymphoid tissue.

• a. epididymis — a small, piriform body attached to the head of the epididymis that is a remnant of the blind cranial segment of the mesonephric duct.
• a. testis — a small cyst adjacent to the head of the epididymis that is a remnant of the paramesonephric (müllerian) duct. Called also Morgagni's hydatid.

(DOD) A document appended to an annex of an operation order, operation plan, or other document to clarify or to give further details.

Look up appendix in Wiktionary, the free dictionary.

Contents 1 See also

Appendix may refer to:

In documents:

• Addendum, any addition to a document, such as a book or legal contract
• Bibliography, a systematic list of books and other works
• Index (publishing), a list of words or phrases with pointers to where related material can be found in a document

In anatomy:

• A section at the end of an organ, in particular:
  • Vermiform appendix (often referred to as simply the "appendix"), a part of the human digestive system
  • Left auricular appendix, a conical pouch on the left atrium of the heart
  • Right auricular appendix, a conical pouch on the right atrium of the heart
  • Appendix of the epididymis, a detached efferent duct of the epididymis
  • Appendix testis, a vestigial remnant of the Müllerian duct
  • Epiploic appendix, one of several small pouches of fat on the peritoneum along the colon and rectum
  • Fibrous appendix of the liver, a band on the left of the liver
  • Appendix of the laryngeal ventricle, a sac that extends from the laryngeal ventricle
  • Mesoappendix, the portion of the mesentery that connects the ileum to the vermiform appendix

See also

• Irregular English plurals—the word "appendix" has irregular plural forms appendixes and appendices

This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - appendiks, tillæg

idioms:

• vermiform appendix    appendiks, blindtarm

Nederlands (Dutch)
appendix, aanhangsel

Français (French)
n. - appendice, (Anat) appendice, annexe

idioms:

• vermiform appendix    appendice vermiforme

Deutsch (German)
n. - Anhang, Blinddarm

idioms:

• vermiform appendix    Wurmfortsatz

Ελληνική (Greek)
n. - παράρτημα, προσθήκη, εξάρτημα, (ανατ.) σκωληκοειδής απόφυση

idioms:

• vermiform appendix    (ανατ.) σκωλικοειδής απόφυση

Italiano (Italian)
appendice

idioms:

• vermiform appendix    appendice vermiforme

Português (Portuguese)
n. - apêndice (m) (Anat.) (Bot.)

idioms:

• vermiform appendix    apêndice (m) vermiforme (Anat.)

Русский (Russian)
приложение, прибавление, отросток, аппендикс

idioms:

• vermiform appendix    аппендикс

Español (Spanish)
n. - anexo, apéndice

idioms:

• vermiform appendix    apéndice vermicular

Svenska (Swedish)
n. - bilaga, tillägg

中文（简体）(Chinese (Simplified))
附录, 附件, 阑尾, 盲肠, 附加物

idioms:

• vermiform appendix    阑尾, 蚓突

中文（繁體）(Chinese (Traditional))
n. - 附錄, 附件, 闌尾, 盲腸, 附加物

idioms:

• vermiform appendix    闌尾, 蚓突

한국어 (Korean)
n. - 부가물, 충수, 가스 조절용 튜브

日本語 (Japanese)
n. - 付録, 追加, 付属物, 虫垂

idioms:

• vermiform appendix    虫垂

العربيه (Arabic)
‏(الاسم) ملحق, الزائده, الزائده الدوديه‏

עברית (Hebrew)
n. - ‮נספח, תוספתן‬

If you are unable to view some languages clearly, click here.

To select your translation preferences click here.