Appendix (anatomy)

The appendix (or vermiform appendix; also cecal [or caecal] appendix; vermix; or vermiform process) is a finger-like, blind-ended tube connected to the cecum, from which it develops in the embryo.

It is typically located on the right side of the body (the same side of the body as the appendix, to which it is joined).

The appendix has been called a vestigial organ, but that interpretation may be changing.

These included the muscles of the ear; wisdom teeth; the appendix; the tail bone; body hair; and the semilunar fold, in the corner of the eye.

The appendix is usually located in the lower right quadrant of the abdomen, near the right hip bone.

The abdominal cavity contains most organs of the digestive system, including the stomach, the small intestine, and the colon with its attached appendix.

The term "vermiform" comes from Latin and means "worm-shaped."

A well known example is the vermiform appendix, a small, blind section of the gut in humans and a number of other mammals.

Its position within the abdomen corresponds to a point on the surface known as McBurney's point.

This point roughly corresponds to the most common location of the base of the appendix where it is attached to the cecum.

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.

The mesoappendix is the portion of the mesocolon connecting the ileum to the appendix.

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.

An appendectomy, also spelled appendicectomy, is a surgical operation in which the vermiform appendix (a portion of the intestine) is removed.

The appendix is usually located in the lower right quadrant of the abdomen, near the right hip bone.

Therefore, the notion that the appendix is only vestigial became widely held.

Examples of vestigial structures are the loss of functional wings in island-dwelling birds; the human appendix and vomeronasal organ; and the hindlimbs of the snake and whale.

The base of the appendix is located 2 cm beneath the ileocecal valve that separates the large intestine from the small intestine. While the base of the appendix is typically located 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.

During colonoscopy, the ileocecal valve is used, along with the appendiceal orifice, in the identification of the cecum.

The most common diseases of the appendix (in humans) are appendicitis and carcinoid tumors (appendiceal carcinoid).

Appendicitis is inflammation of the appendix.

Appendix cancer accounts for about 1 in 200 of all gastrointestinal malignancies.

Appendix cancer are very rare cancers of the vermiform appendix.

The most common diseases of the appendix (in humans) are appendicitis and carcinoid tumors (appendiceal carcinoid).

Carcinoid tumors of the midgut (jejunum, ileum, appendix, and cecum) are associated with carcinoid syndrome.

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.

The GALT also includes the Peyer's patches of the small intestine, isolated lymphoid follicles present throughout the intestine and the appendix in humans.

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 Mitrofanoff procedure also known as the Mitrofanoff appendicovesicostomy, is a surgical procedure in which the appendix is used to create a conduit between the skin surface and the urinary bladder.

This reservoir of bacteria could then serve to repopulate the gut flora in the digestive system following a bout of dysentery or cholera or to boost it following a milder gastrointestinal illness.

It is also the site of the appendix attachment.

This valve of the vermiform appendix is also called Gerlach's valve.

This anatomical structure is a fold of membrane sometimes found at the opening of the vermiform appendix.

Pain often begins in the center of the abdomen, corresponding to the appendix's development as part of the embryonic midgut.

The cecum is a pouchlike structure of the colon, located at the junction of the small and the large intestines.

The cecum is the first section of the colon and involved in the digestion, while the appendix which develops embryologically from it, is a structure of the colon, not involved in digestion and considered to be part of the gut-associated lymphoid tissue.

Research performed at Winthrop–University Hospital showed that individuals without an appendix were four times as likely to have a recurrence of Clostridium difficile colitis.

While the base of the appendix is typically located 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.

These include most of the stomach, first part of the duodenum, all of the small intestine, caecum and appendix, transverse colon, sigmoid colon and rectum.

The appendicular vein is the vein which drains blood from the vermiform appendix.

This peritoneal inflammation, or peritonitis, results in rebound tenderness (pain upon removal of pressure rather than application of pressure).

The stage magician Harry Houdini died this way, having contracted streptococcus peritonitis after his appendix ruptured and was removed too late to prevent spread of the infection.

It descends behind the termination of the ileum and enters the mesoappendix of the vermiform appendix.