Peritoneum Health Dictionary

A procedure used to ?lter o? waste products from the blood and remove surplus ?uid from the body in someone who has kidney failure (see KIDNEYS, DISEASES OF). The scienti?c process involves separating crystalloid and COLLOID substances from a solution by interposing a semi-permeable membrane between the solution and pure water. The crystalloid substances pass through the membrane into the water until a state of equilibrium, so far as the crystalloid substances are concerned, is established between the two sides of the membrane. The colloid substances do not pass through the membrane.

Dialysis is available as either haemodialysis or peritoneal dialysis.

Haemodialysis Blood is removed from the circulation either through an arti?cial arteriovenous ?stula (junction) or a temporary or permanent internal catheter in the jugular vein (see CATHETERS). It then passes through an arti?cial kidney (‘dialyser’) to remove toxins (e.g. potassium and urea) by di?usion and excess salt and water by ultra?ltration from the blood into dialysis ?uid prepared in a ‘proportionator’ (often referred to as a ‘kidney machine’). Dialysers vary in design and performance but all work on the principle of a semi-permeable membrane separating blood from dialysis ?uid. Haemodialysis is undertaken two to three times a week for 4–6 hours a session.

Peritoneal dialysis uses the peritoneal lining (see PERITONEUM) as a semi-permeable membrane. Approximately 2 litres of sterile ?uid is run into the peritoneum through the permanent indwelling catheter; the ?uid is left for 3–4 hours; and the cycle is repeated 3–4 times per day. Most patients undertake continuous ambulatory peritoneal dialysis (CAPD), although a few use a machine overnight (continuous cycling peritoneal dialysis, CCPD) which allows greater clearance of toxins.

Disadvantages of haemodialysis include cardiovascular instability, HYPERTENSION, bone disease, ANAEMIA and development of periarticular AMYLOIDOSIS. Disadvantages of peritoneal dialysis include peritonitis, poor drainage of ?uid, and gradual loss of overall e?ciency as endogenous renal function declines. Haemodialysis is usually done in outpatient dialysis clinics by skilled nurses, but some patients can carry out the procedure at home. Both haemodialysis and peritoneal dialysis carry a relatively high morbidity and the ideal treatment for patients with end-stage renal failure is successful renal TRANSPLANTATION.... dialysis

In?ammation of the PERITONEUM. It may be acute or chronic, localised or generally di?used, and its severity and danger may vary according to the cause.

Acute peritonitis generally arises because bacteria enter the peritoneal cavity, from penetrating wounds, e.g. stabs, from the exterior or from the abdominal organs. Hence conditions leading to perforation of the STOMACH, INTESTINE, BILE DUCT, URINARY BLADDER, and other hollow organs such as gastric ulcer (see STOMACH, DISEASES OF), typhoid fever (see ENTERIC FEVER), gall-stones (see under GALLBLADDER, DISEASES OF), rupture of the bladder, strangulated HERNIA, and obstructions of the bowels, may lead to peritonitis. Numerous bacteria may cause the in?ammation, most common being E. coli, streptococci and the gonococcus.

The symptoms usually begin with a RIGOR together with fever, vomiting, severe abdominal pain and tenderness. Shock develops and the abdominal wall becomes rigid. If untreated the patient usually dies. Urgent hospital admission is required. X-ray examination may show gas in the peritoneal cavity. Treatment consists of intravenous ?uids, antibiotics and surgical repair of the causative condition. Such treatment, together with strong analgesics is usually successful if started soon enough.... peritonitis

Mesentery is the double layer of peritoneal membrane which supports the small INTESTINE. It is of a fan shape, and its shorter edge is attached to the back wall of the abdomen for a distance of about 15 cm (6 inches), while the small intestine lies within its longer edge, for a length of over 6 metres (20 feet). The terms mesocolon, mesorectum, etc., are applied to similar folds of PERITONEUM that support parts of the colon, rectum, etc.... mesentery

The double fold of PERITONEUM by which the large INTESTINE is suspended from the back wall of the abdomen.... mesocolon

A long fold of peritoneal membrane (see PERITONEUM), generally loaded with more or less fat, which hangs down within the cavity of the ABDOMEN in front of the bowels. It is formed by the layers of peritoneum that cover the front and back surfaces of the stomach in their passage from the lower margin of this organ to cover the back and front surfaces of the large intestine. Instead of passing straight from one organ to the other, these layers dip down and form a sort of fourfold apron. This omentum is known as the greater omentum, to distinguish it from two smaller peritoneal folds, one of which passes between the liver and stomach (the hepatogastric omentum), and the other between the liver and duodenum (the hepatoduodenal omentum). Together they are known as the lesser omentum.... omentum

The lower part of the trunk. Above, and separated from it by the diaphragm, lies the thorax or chest, and below lies the PELVIS, generally described as a separate cavity though continuous with that of the abdomen. Behind are the SPINAL COLUMN and lower ribs, which come within a few inches of the iliac bones. At the sides the contained organs are protected by the iliac bones and down-sloping ribs, but in front the whole extent is protected only by soft tissues. The latter consist of the skin, a varying amount of fat, three layers of broad, ?at muscle, another layer of fat, and ?nally the smooth, thin PERITONEUM which lines the whole cavity. These soft tissues allow the necessary distension when food is taken into the STOMACH, and the various important movements of the organs associated with digestion. The shape of the abdomen varies; in children it may protrude considerably, though if this is too marked it may indicate disease. In healthy young adults it should be either slightly prominent or slightly indrawn, and should show the outline of the muscular layer, especially of the pair of muscles running vertically (recti), which are divided into four or ?ve sections by transverse lines. In older people fat is usually deposited on and inside the abdomen. In pregnancy the abdomen enlarges from the 12th week after conception as the FETUS in the UTERUS grows (see PREGNANCY AND LABOUR; ANTENATAL CARE).

Contents The principal contents of the abdominal cavity are the digestive organs, i.e. the stomach and INTESTINE, and the associated glands, the LIVER and PANCREAS. The position

of the stomach is above and to the left when the individual is lying down, but may be much lower when standing. The liver lies above and to the right, largely under cover of the ribs, and occupying the hollow of the diaphragm. The two KIDNEYS lie against the back wall on either side, protected by the last two ribs. From the kidneys run the URETERS, or urinary ducts, down along the back wall to the URINARY BLADDER in the pelvis. The pancreas lies across the spine between the kidneys, and on the upper end of each kidney is a suprarenal gland

(see ADRENAL GLANDS). The SPLEEN is positioned high up on the left and partly behind the stomach. The great blood vessels and nerves lie on the back wall, and the remainder of the space is taken up by the intestines or bowels (see INTESTINE). The large intestine lies in the ?anks on either side in front of the kidneys, crossing below the stomach from right to left, while the small intestine hangs from the back wall in coils which ?ll up the spaces between the other organs. Hanging down from the stomach in front of the bowels is the OMENTUM, or apron, containing much fat and helping to protect the bowels. In pregnancy the UTERUS, or womb, rises up from the pelvis into the abdomen as it increases in size, lifting the coils of the small intestine above it.

The PELVIS is the part of the abdomen within the bony pelvis (see BONE), and contains the rectum or end part of the intestine, the bladder, and in the male the PROSTATE GLAND; in the female the uterus, OVARIES, and FALLOPIAN TUBES.... abdomen

The membrane lining various vessels and cavities of the body, such as the pleura (lining the lung), the pericardium (lining the heart), the peritoneum (lining the abdomen and abdominal organs), the lymphatic vessels, blood vessels, and joints. It consists of a ?brous layer covered with thin ?at cells, which render the surface perfectly smooth and secrete the ?uid for its lubrication.... endothelium

A substance formed in the BLOOD as it clots: indeed, its formation causes clotting. The substance is produced in threads; after the threads have formed a close meshwork through the blood, they contract, and produce a dense, felted mass. The substance is formed not only from shed blood but also from LYMPH which exudes from the lymph vessels. Thus ?brin is found in all in?ammatory conditions within serous cavities like the PLEURA, PERITONEUM, and PERICARDIUM, and forms a thick coat upon the surface of the in?amed membranes. It is also found in in?amed joints, and in the lung as a result of pneumonia. (See COAGULATION.)... fibrin

A sign obtained from collections of ?uid by laying the ?ngers of one hand upon one side of the swelling, and, with those of the other, tapping or pressing suddenly on a distant point of the swelling. The ‘thrill’ communicated from one hand to the other through the ?uid is one of the most important signs of the presence of an ABSCESS, or of e?usion of ?uid into joints or into the peritoneal cavity (see PERITONEUM).... fluctuation

See under STOMACH, DISEASES OF; INTESTINE, DISEASES OF; DIARRHOEA; LIVER, DISEASES OF; PANCREAS, DISEASES OF; GALL-BLADDER, DISEASES OF; KIDNEYS, DISEASES OF; URINARY BLADDER, DISEASES OF; HERNIA; PERITONITIS; APPENDICITIS; TUMOUR.

Various processes that can occur include in?ammation, ulceration, infection or tumour. Abdominal disease may be of rapid onset, described as acute, or more long-term when it is termed chronic.

An ‘acute abdomen’ is most commonly caused by peritonitis – in?ammation of the membrane that lines the abdomen. If any structure in the abdomen gets in?amed, peritonitis may result. Causes include injury, in?ammation of the Fallopian tubes (SALPINGITIS), and intestinal disorders such as APPENDICITIS, CROHN’S DISEASE, DIVERTICULITIS or a perforated PEPTIC ULCER. Disorders of the GALLBLADDER or URINARY TRACT may also result in acute abdominal pain.

General symptoms of abdominal disease include:

Pain This is usually ill-de?ned but can be very unpleasant, and is termed visceral pain. Pain is initially felt near the mid line of the abdomen. Generally, abdominal pain felt high up in the mid line originates from the stomach and duodenum. Pain that is felt around the umbilicus arises from the small intestine, appendix and ?rst part of the large bowel, and low mid-line pain comes from the rest of the large bowel. If the diseased organ secondarily in?ames or infects the lining of the abdominal wall – the PERITONEUM – peritonitis occurs and the pain becomes more de?ned and quite severe, with local tenderness over the site of the diseased organ itself. Hence the pain of appendicitis begins as a vague mid-line pain, and only later moves over to the right iliac fossa, when the in?amed appendix has caused localised peritonitis. PERFORATION of one of the hollow organs in the abdomen – for example, a ruptured appendix or a gastric or duodenal ulcer (see STOMACH, DISEASES OF) eroding the wall of the gut – usually causes peritonitis with resulting severe pain.

The character of the pain is also important. It may be constant, as occurs in in?ammatory diseases and infections, or colicky (intermittent) as in intestinal obstruction.

Swelling The commonest cause of abdominal swelling in women is pregnancy. In disease, swelling may be due to the accumulation of trapped intestinal contents within the bowel, the presence of free ?uid (ascites) within the abdomen, or enlargement of one or more of the abdominal organs due to benign causes or tumour.

Constipation is the infrequent or incomplete passage of FAECES; sometimes only ?atus can be passed and, rarely, no bowel movements occur (see main entry for CONSTIPATION). It is often associated with abdominal swelling. In intestinal obstruction, the onset of symptoms is usually rapid with complete constipation and severe, colicky pain. In chronic constipation, the symptoms occur more gradually.

Nausea and vomiting may be due to irritation of the stomach, or to intestinal obstruction when it may be particularly foul and persistent. There are also important non-abdominal causes, such as in response to severe pain or motion sickness.

Diarrhoea is most commonly due to simple and self-limiting infection, such as food poisoning, but may also indicate serious disease, especially if it is persistent or contains blood (see main entry for DIARRHOEA).

Jaundice is a yellow discoloration of the skin and eyes, and may be due to disease in the liver or bile ducts (see main entry for JAUNDICE).

Diagnosis and treatment Abdominal diseases are often di?cult to diagnose because of the multiplicity of the organs contained within the abdomen, their inconstant position and the vagueness of some of the symptoms. Correct diagnosis usually requires experience, often supplemented by specialised investigations such as ULTRASOUND. For this reason sufferers should obtain medical advice at an early stage, particularly if the symptoms are severe, persistent, recurrent, or resistant to simple remedies.... abdomen, diseases of

The condition in which the endometrium (the cells lining the interior of the UTERUS) is found in other parts of the body. The most common site of such misplaced endometrium is the muscle of the uterus. The next most common site is the ovary (see OVARIES), followed by the PERITONEUM lining the PELVIS, but it also occurs anywhere in the bowel. The cause is not known. Endometriosis never occurs before puberty and seldom after the menopause. The main symptoms it produces are MENORRHAGIA, DYSPAREUNIA, painful MENSTRUATION and pelvic pain. Treatment is usually by removal of the affected area, but in some cases satisfactory results are obtained from the administration of a PROGESTOGEN such as NORETHISTERONE, norethynodrel and DANAZOL.... endometriosis

An extrusion of the abdominal PERITONEUM, sometimes containing a loop of bowel, through natural openings in the region of either groin (see HERNIA).... inguinal hernia

A general term applied to any operation in which the abdominal cavity is opened (see ABDOMEN). A laparotomy may be exploratory to establish a diagnosis, or carried out as a preliminary to major surgery. Viewing of the peritoneal cavity (see PERITONEUM) through an ENDOSCOPE is called a LAPAROSCOPY or peritoneoscopy.... laparotomy

A rare malignant TUMOUR of adipose or fatty tissue. It occurs most frequently in the thighs, buttocks or retro-peritoneum. The four main types are: well di?erentiated; myxoid; round cell; and pleomorphic (variety of forms).... liposarcoma

A localised in?ammation of the PERITONEUM surrounding the UTERUS.... perimetritis

A collection of air in the peritoneal cavity (see PERITONEUM). Air introduced into the peritoneal cavity collects under the diaphragm which is thus raised and collapses the lungs. This procedure was sometimes carried out in the treatment of pulmonary tuberculosis in the pre-antibiotic days as an alternative to arti?cial PNEUMOTHORAX.... pneumoperitoneum

Lymph is the ?uid which circulates in the lymphatic vessels of the body. It is a colourless ?uid, like blood PLASMA in composition, only rather more watery. It contains salts similar to those of blood plasma, and the same proteins, although in smaller amount: FIBRINOGEN, serum albumin (see ALBUMINS), and serum GLOBULIN. It also contains lymphocytes (white blood cells), derived from the glands. In some lymphatic vessels, the lymph contains, after meals, a great amount of FAT in the form of a ?ne milky emulsion. These are the vessels which absorb fat from the food passing down the INTESTINE, and convey it to the thoracic duct; they are called lacteals because their contents look milky (see CHYLE).

The lymph is derived, initially, from the blood, the watery constituents of which exude through the walls of the CAPILLARIES into the tissues, conveying material for the nourishment of the tissues and absorbing waste products.

The spaces in the tissues communicate with lymph capillaries, which have a structure similar to that of the capillaries of the blood-vessel system, being composed of delicate ?at cells joined edge to edge. These unite to form ?ne vessels, resembling minute veins in structure, called lymphatics, which ramify throughout the body, passing through lymphatic glands and ultimately discharging their contents into the jugular veins in the root of the neck. Other lymph vessels commence in great numbers as minute openings on the surface of the PLEURA and PERITONEUM, and act as drains for these otherwise closed cavities. When ?uid is e?used into these cavities – as in a pleural e?usion, for example – its absorption takes place through the lymphatic vessels. The course of these vessels is described under the entry on GLAND.

Lymph circulates partly by reason of the pressure at which it is driven through the walls of the blood capillaries, but mainly in consequence of incidental forces. The lymph capillaries and vessels are copiously provided with valves, which prevent any back ?ow of lymph, and every time these vessels are squeezed (as by the contraction of a muscle, or movement of a limb) the lymph is pumped along.

The term lymph is also applied to the serous ?uid contained in the vesicles which develop as the result of vaccination, and used for the purpose of vaccinating other individuals.... lymph

These are smooth, transparent membranes that line certain large cavities of the body. The chief serous membranes are the PERITONEUM, lining the cavity of the abdomen; the pleurae (see PLEURA), one of which lines each side of the chest, surrounding the corresponding lung; the PERICARDIUM, in which the heart lies; and the tunica vaginalis on each side, enclosing a testicle. The name of these membranes is derived from the fact that the surface is moistened by thin ?uid derived from the serum of blood or LYMPH. Every serous membrane consists of a visceral portion, which closely envelops the organs concerned, and a parietal portion, which adheres to the wall of the cavity. These two portions are continuous with one another so as to form a closed sac, and the opposing surfaces are close together, separated only by a little ?uid. This arrangement enables the organs in question to move freely within the cavities containing them. For further details, see under PERITONEUM.... serous membranes

Also known as meteorism. Distension of the abdomen due to the presence of gas or air in the INTESTINE or in the peritoneal cavity (see PERITONEUM). The abdomen when struck with the ?ngers, gives under these conditions a drum-like (tympanitic) note.... tympanites

A type of epithelium covering the peritoneum, the pleura, and the pericardium.... mesothelium

a bluish bruiselike appearance around the umbilicus due to bleeding into the peritoneum. Causes include a ruptured ectopic pregnancy and acute *pancreatitis. [T. S. Cullen (1868–1953), US gynaecologist]... cullen sign

(umbilical hernia) n. a congenital defect in which the abdominal wall fails to close during fetal development and bowel, covered by peritoneum, herniates through the umbilical cord. Unlike *gastroschisis, it is associated with other structural fetal abnormalities. It can be corrected by surgery.... exomphalos

a fold of peritoneum separating the right and left lobes of the liver and attaching it to the diaphragm and the anterior abdominal wall as far as the umbilicus.... falciform ligament

A hollow, triangular organ, ?attened from front to back, the lower angle (or cervix) commincates through a narrow opening (the os uteri) with the VAGINA. The uterus or womb is where the fertilised ovum (egg) normally becomes embedded and in which the EMBRYO and FETUS develop. The normal uterus weighs 30–40 g; during pregnancy, however, enormous growth occurs together with muscular thickening (see MUSCLE – Development of muscle). The cavity is lined by a thick, soft, mucous membrane, and the wall is chie?y composed of muscle ?bres arranged in three layers. The outer surface, like that of other abdominal organs, is covered by a layer of PERITONEUM. The uterus has a copious supply of blood derived from the uterine and ovarian arteries. It has also many lymphatic vessels, and its nerves establish wide connections with other organs (see PAIN). The position of the uterus is in the centre of the PELVIS, where it is suspended by several ligaments between the URINARY BLADDER in front and the RECTUM behind. On each side of the uterus are the broad ligaments passing outwards to the side of the pelvis, the utero-sacral ligament passing back to the sacral bone, the utero-vesical ligament passing forwards to the bladder, and the round ligament uniting the uterus to the front of the abdomen.... uterus

A variety of diseases caused by inhalation of asbestos fibres. Asbestos is a fibrous mineral formerly used as a heat- and fire-resistant insulating material. There are 3 main types of asbestos fibre: white, which is widely used; blue; and brown, the most dangerous. The use of all types is now carefully controlled.

In asbestosis, widespread fine scarring occurs in the lungs. The disease causes breathlessness and a dry cough, eventually leading to severe disability and death. It develops mostly in industrial workers who have been heavily exposed to asbestos. The period from initial exposure to development of the disease is usually at least 20 years. Diagnosis is by chest X-ray. Asbestosis increases the risk of lung cancer.

Mesothelioma is a cancerous tumour of the pleura (the membrane surrounding the lungs) or the peritoneum (the membrane lining the abdominal cavity). In the pleura, mesotheliomas cause pain and breathlessness; in the peritoneum they cause enlargement of the abdomen and intestinal obstruction. The condition cannot be treated and usually leads to death within 1 or 2 years. The average interval between initial exposure to asbestos and death is 20–30 years. Mesothelioma affects people who have worked with blue or brown asbestos.

In diffuse pleural thickening, the outer and inner layers of the pleura become thickened, and excess fluid may accumulate in the cavity between them.

This combination restricts the ability of the lungs to expand, resulting in shortness of breath.

The condition may develop even after short exposure to asbestos.... asbestos-related diseases

Excess fluid in the peritoneal cavity, the space between the 2- layered membrane that lines the inside of the abdominal wall and which covers the abdominal organs.

Ascites may occur in any condition that causes generalized oedema, such as congestive heart failure, nephrotic syndrome, and cirrhosis of the liver. Ascites may occur in cancer if metastases (secondary growths) from a cancer elsewhere in the body develop in the peritoneum. The condition also occurs if tuberculosis affects the abdomen.

Ascites causes abdominal swelling and discomfort. It may cause breathing difficulty due to pressure on the diaphragm. The underlying cause is treated if possible. Diuretic drugs, particularly spironolactone, are often used to treat ascites associated with cirrhosis.... ascites

a technique used in laparoscopic surgery in which the skin, muscle, fascia, and peritoneum are incised under direct vision to allow the insertion of a blunt *trocar, through which the laparoscope is introduced. [H. M. Hasson (21st century), US gynaecologist]... hasson technique

n. the protrusion of an organ or tissue out of the body cavity in which it normally lies. An inguinal hernia (or rupture) occurs in the lower abdomen; a sac of peritoneum, containing fat or part of the bowel, bulges through a weak part (inguinal canal) of the abdominal wall. It may result from physical straining or coughing. A scrotal hernia is an inguinal hernia so large that it passes into the scrotum; a femoral hernia is similar to an inguinal hernia but protrudes at the top of the thigh, through the point at which the femoral artery passes from the abdomen to the thigh. Other hernias of the abdominal wall include periumbilical, epigastric, and postsurgical hernias. A diaphragmatic hernia is the protrusion of an abdominal organ through the diaphragm into the chest cavity; the most common type is the hiatus hernia, in which the stomach passes partly or completely into the chest cavity through the opening (hiatus) for the oesophagus. This may be associated with *gastro-oesophageal reflux, although most patients have no symptoms.

Hernias may be complicated by becoming impossible to return to their normal site (irreducible); swollen and fixed within their sac (incarcerated); or cut off from their blood supply, becoming painful and eventually gangrenous (strangulated). The best treatment for hernias, especially if they are painful, is surgical repair (see hernioplasty).... hernia

n. a glucose polymer solution produced by the hydrolysis of cornstarch and containing a spectrum of polymer molecules with an average molecular weight of 16,200 Da. It is used in the dialysate treatment of renal failure by *peritoneal dialysis. It exerts a strong osmotic effect, allowing removal of fluid without exposing the peritoneum to high levels of glucose. It is of most use when the dialysate is required to remain within the body for a long period, for instance overnight during chronic ambulatory peritoneal dialysis or during the day with automated peritoneal dialysis.... icodextrin

combining form denoting inflammation of an organ, tissue, etc. Examples: arthritis (of a joint); peritonitis (of the peritoneum).... itis

n. 1. a tough band of white fibrous connective tissue that links two bones together at a joint. Ligaments are inelastic but flexible; they both strengthen the joint and limit its movements to certain directions. 2. a sheet of peritoneum that supports or links together abdominal organs.... ligament

(peritoneoscopy) n. examination of the abdominal structures (which are contained within the peritoneum) by means of a *laparoscope. This is passed through a small incision in the wall of the abdomen after insufflating carbon dioxide into the abdominal cavity (creating a *pneumoperitoneum). Laparoscopy enables visual assessment of abdominal organs, harvesting of biopsies, and cancer staging. Therapeutic uses include aspiration of cysts, division of adhesions, and surgery that would previously have required *laparotomy. Examples include *hysterectomy, *cholecystectomy, *fundoplication, *prostatectomy, *colectomy, *nephrectomy, *oophorectomy, Fallopian tube ligation, and ova collection for *in vitro fertilization. See also minimally invasive surgery. —laparoscopic adj.... laparoscopy

the lower portion of uterus, lying below the loose fold of peritoneum that lies between the uterus and bladder. This does not form until later in pregnancy and is less contractile than the rest of the uterus. A *Caesarean section is performed through the lower segment.... lower uterine segment

n. a fold of peritoneum that surrounds the Fallopian tubes. It is the upper part of the broad ligament that surrounds the uterus.... mesosalpinx

n. a tumour of the pleura, peritoneum, or pericardium. The occurrence of pleural mesothelioma is often due to exposure to asbestos dust (see asbestosis), and workers in the asbestos industry who develop such tumours are entitled to industrial compensation. In other cases there is no history of direct exposure to asbestos at work but the patients had been exposed to asbestos via the clothes of relatives who had had direct contact with asbestos, or they themselves had lived very close to an asbestos factory. There is no curative treatment for the disease, but moderately good results have occasionally been obtained from radical surgery for limited disease, from radiotherapy, and more recently from chemotherapy.... mesothelioma

n. the spread of a malignant tumour from its site of origin. This occurs by three main routes: (1) through the bloodstream (haematogenous); (2) through the lymphatic system; (3) across body cavities, e.g. through the peritoneum (see transcoelomic spread). Highly malignant tumours have a greater potential for metastasis. Individual tumours may spread by one or all of the above routes, although *carcinoma is said classically to metastasize via the lymphatics and *sarcoma via the bloodstream. —metastatic adj.... metastasis

n. the surgical removal of all or part of the omentum (the fold of peritoneum between the stomach and other abdominal organs). In infracolic omentectomy the lower section of the greater omentum is excised as part of the management of ovarian or bowel cancer. It enables accurate staging and optimal reduction of the cancer.... omentectomy

adj. 1. of or relating to the inner walls of a body cavity, as opposed to the contents: applied particularly to the membranes lining a cavity (see peritoneum; pleura). 2. of or relating to the parietal bone.... parietal

n. the *peritoneum of the uterus.... perimetrium

(PD) a form of renal replacement therapy (see dialysis) that utilizes the peritoneum as the semipermeable membrane separating blood and *dialysate. Peritoneal dialysis can be given as a temporary and emergency treatment using a rigid percutaneous cannula to deliver fluid into the peritoneal cavity; this cannula usually needs removal and/or replacement within a few days. Alternatively, PD can be used as a chronic treatment, either in the form of chronic ambulatory peritoneal dialysis (see CAPD) or automated peritoneal dialysis (APD), in which case fluid delivery is through a soft silastic catheter that is tunnelled subcutaneously out of the peritoneal cavity and is designed to stay in place for years. In all cases, the dialysis fluid is left within the peritoneal cavity for a period of time during which substances in the bloodstream diffuse into the fluid according to their concentration gradient and the permeability of the peritoneal membrane.... peritoneal dialysis

n. 1. (in anatomy) a small sac-like structure, especially occurring as an outgrowth of a larger structure. The pouch of Douglas is a pouch of peritoneum occupying the space between the rectum and uterus. 2. (in surgery) a sac created from a loop of intestine and used to replace a section of rectum that has been surgically removed, for example in the treatment of ulcerative colitis (see ileal pouch), or to replace the bladder after *cystectomy.... pouch

n. a mucoid tumour of the peritoneum, often seen in association with *myxomas of the ovary. In pseudomyxoma peritonei there are recurrent deposits of mucin-producing cells in the abdomen, which can be difficult to clear by surgery and may prove fatal.... pseudomyxoma

prefix denoting at the back or behind. Examples: retrobulbar (at the back of the eyeball); retroperitoneal (behind the peritoneum).... retro

(RPF) a condition in which a dense plaque of fibrous tissue develops behind the peritoneum adjacent to the abdominal aorta. It may be secondary to malignancy, medication (methysergide, beta blockers), aortic aneurysm, or certain infections. The ureters become encased and hence obstructed, causing acute *anuria and renal failure. The obstruction can be relieved by *nephrostomy or the insertion of double J *stents. In the acute phase steroid administration may help, but in established RPF *ureterolysis is required.... retroperitoneal fibrosis

the region between the posterior parietal *peritoneum and the front of the *lumbar vertebrae. It contains important structures, including the kidneys, adrenal glands, pancreas, lumbar spinal nerve roots, sympathetic ganglia and nerves, and the abdominal *aorta and its major branches.... retroperitoneal space

(serosa) a smooth transparent membrane, consisting of *mesothelium and underlying elastic fibrous connective tissue, lining certain large cavities of the body. The *peritoneum of the abdomen, *pleura of the chest, and *pericardium of the heart are all serous membranes. Each consists of two portions: the parietal portion lines the walls of the cavity, and the visceral portion covers the organs concerned. The two are continuous, forming a closed sac with the organs essentially outside the sac. The inner surface of the sac is moistened by a thin fluid derived from blood serum, which allows frictionless movement of organs within their cavities. Compare mucous membrane.... serous membrane

n. a passage connecting two anatomical channels or sites, thus diverting blood or other fluid (e.g. cerebrospinal fluid) from one to the other. It may occur as a congenital abnormality (as in *septal defects of the heart) or be surgically created; for example, a ventriculoperitoneal shunt is created to transfer excess cerebrospinal fluid in hydrocephalus from the ventricles to the peritoneum. See also anastomosis.... shunt

a one-way valve used to drain cerebrospinal fluid in order to control *hydrocephalus. The device is inserted into the ventricles of the brain and passes via a subcutaneous tunnel to drain into either the right atrium or the peritoneum.... spitz–holter valve