is most common in obese people. The
affected skin is red and moist and may
have an odour, often with a fungal infec-
tion such as candidiasis; there may also
be scales or blisters. The condition wors-
ens with sweating. Treatment consists of
weight reduction and keeping the affected
areas clean and dry. A cream containing
a corticosteroid and/or antifungal drugis
used if candidiasis is present.
intervertebral discSee disc, interver-
tebral.
intestinal imagingSee barium X-ray
examinations.
intestinal lipodystrophySee Whip-
ple’s disease.
intestineThe major part of the digestive
tract (see digestive system), extending
from the exit of the stomach to the anus.
It forms a long tube divided into 2 main
sections: the small and large intestines.
The small intestine is about 6.5 m in
length and has 3 sections: the duode-
num, the jejunumand the ileum. Partially
digested food from the stomach is
forced along the intestine by peristalsis.
The small intestine is concerned with
the digestion and absorption of food.
Digestive enzymes and bile are added to
the partly digested food in the duodenum
via the bile and pancreatic ducts (see
biliary system). Glands within the walls of
each section of the small intestine pro-
duce mucus and other enzymes, which
help to break down the food. Blood
vessels in the intestinal walls absorb
nutrients and carry them to the liver for
distribution to the rest of the body.
The large intestine is about 1.5 m long.
The main section, the colon, is divided
into an ascending, a transverse, a
descending, and a pelvic portion (the
sigmoid colon). The appendixhangs from
a pouch (the caecum) between the small
intestine and the colon. The final sec-
tion before the anus is the rectum.
Unabsorbed material leaves the small
intestine as liquid and fibre. As this
material passes through the large intes-
tine, water, vitamins, and mineral salts are
absorbed into the bloodstream, leaving
faeces made up of undigested food resi-
due, fat, various secretions, and bacteria.
The faeces are compressed and pass
into the rectum for evacuation.intestine, cancer ofA malignant tumour
in the intestine. Both the small and large
intestine may develop carcinoid tumours
(leading to carcinoid syndrome) and
lymphomas. Cancer of the small intestine
is rare, but cancer of the large intestine is
one of the most common of all cancers
(see colon, cancer of; rectum, cancer of).
intestine, disorders ofThe intestine is
subject to various structural abnormali-
ties and to the effects of many infective
organisms and parasites; it may also be
affected by tumours and other disorders.
Structural abnormalities may be pre-
sent from birth (congenital) or may
develop later. They cause blockage of the
intestine (see intestine, blockage of) and
include atresia, stenosis, and volvulus. In
newborns, meconium (fetal intestinal
contents) may block the intestine.
Generalized inflammation of the intes-
tine may result from viral or bacterial
infections or from noninfectious causes,
as in ulcerative colitisand Crohn’s disease.
Gastroenteritisis the term commonly ap-
plied to inflammation of the stomach and
intestines. Infection encompasses food
poisoning, traveller’s diarrhoea, typhoid
fever, cholera, amoebiasis, and giardiasis.
Intestinal worm infestations include
roundworms and tapeworms. Some-
times inflammation is localized, such as
in appendicitisand diverticular disease.
Tumours of the small intestine are rare,
but noncancerous growths, lymphomas,
and carcinoid tumours (causing carcinoid
syndrome) occur. Tumours of the large
intestine are common (see colon, cancer
of; rectum, cancer of). Some forms of
familial polyposismay progress to cancer.
Impaired blood supply (ischaemia) to
the intestine may occur as a result of
partial or complete obstruction of the
arteries in the abdominal wall (from dis-
eases such as atherosclerosis) or from
the blood vessels being compressed or
trapped, as in intussusceptionor hernias.
Loss of blood supply may cause gangrene.
Other disorders that affect the intestine
includepeptic ulcers, diverticulosis, mal-
absorption, coeliac disease, and irritable
bowel syndrome.
intestine, obstruction ofA partial or
complete blockage of the small or large
intestine. Causes include a strangulatedINTERVERTEBRAL DISC INTESTINE, OBSTRUCTION OFI