The abdominal cavity is a large

body cavity A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid. The two largest human body cavities are the ventral body cavity, and ...

in humans and many other

animal Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage ...

s that contains many organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

-shaped roof is the

thoracic diaphragm The thoracic diaphragm, or simply the diaphragm ( grc, διάφραγμα, diáphragma, partition), is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the m ...

, a thin sheet of muscle under the lungs, and its floor is the

pelvic inlet The pelvic inlet or superior aperture of the pelvis is a planar surface which defines the boundary between the pelvic cavity and the abdominal cavity (or, according to some authors, between two parts of the pelvic cavity, called lesser pelvis an ...

, opening into the

pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

Structure

Organs

Organs of the abdominal cavity include the stomach,

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it i ...

, gallbladder,

spleen The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .

pancreas The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an ...

small intestine The small intestine or small bowel is an organ (anatomy), organ in the human gastrointestinal tract, gastrointestinal tract where most of the #Absorption, absorption of nutrients from food takes place. It lies between the stomach and large intes ...

, kidneys, large intestine, and

adrenal gland The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex ...

Peritoneum

The abdominal cavity is lined with a protective membrane termed the

peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mes ...

. The inside wall is covered by the parietal peritoneum. The

kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blo ...

s are located behind the peritoneum, in the retroperitoneum, outside the abdominal cavity. The viscera are also covered by visceral peritoneum. Between the visceral and parietal peritoneum is the peritoneal cavity, which is a potential space. It contains a serous fluid called

peritoneal fluid Peritoneal fluid is a serous fluid made by the peritoneum in the abdominal cavity which lubricates the surface of tissue that lines the abdominal wall and pelvic cavity. It covers most of the organs in the abdomen. An increased volume of peritone ...

that allows motion. This motion is apparent of the gastrointestinal tract. The peritoneum, by virtue of its connection to the two (parietal and visceral) portions, gives support to the abdominal organs. The peritoneum divides the cavity into numerous compartments. One of these the

lesser sac The lesser sac, also known as the omental bursa, is a part of the peritoneal cavity that is formed by the lesser and greater omentum. Usually found in mammals, it is connected with the greater sac via the omental foramen or ''Foramen of Wins ...

is located behind the stomach and joins into the

greater sac In human anatomy, the greater sac, also known as the general cavity (of the abdomen) or peritoneum of the peritoneal cavity proper, is the cavity in the abdomen that is inside the peritoneum but outside the lesser sac. It is connected with the l ...

via the

foramen of Winslow In human anatomy, the omental foramen (epiploic foramen, foramen of Winslow after the anatomist Jacob B. Winslow, or uncommonly aditus; la, Foramen epiploicum), is the passage of communication, or foramen, between the greater sac (general cavity ...

. Some of the organs are attached to the walls of the abdomen via folds of peritoneum and

ligament A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the: * Peritoneal l ...

s, such as the

and others use broad areas of the peritoneum, such as the

. The peritoneal ligaments are actually dense folds of the peritoneum that are used to connect viscera to viscera or viscera to the walls of the abdomen. They are named in such a way as to show what they connect typically. For example, the gastrocolic ligament connects the stomach and colon and the

splenocolic ligament The splenocolic ligament is a peritoneal ligament connecting the splenic capsule to the transverse colon.Wood et al. 2010, p. 611 Made of visceral peritoneum, it lies between the greater omentum and the transverse mesocolon. It has three attach ...

connects the

spleen The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .

and the colon, or sometimes by their shape as the round ligament or triangular ligament.

Mesentery

Mesenteries are folds of peritoneum that are attached to the walls of the abdomen and enclose viscera completely. They are supplied with plentiful amounts of

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

. The three most important mesenteries are mesentery for the

, the transverse mesocolon, which attaches the back portion of the colon to the abdominal wall, and the sigmoid mesocolon which enfolds the

sigmoid colon The sigmoid colon (or pelvic colon) is the part of the large intestine that is closest to the rectum and anus. It forms a loop that averages about in length. The loop is typically shaped like a Greek letter sigma (ς) or Latin letter S (thus ' ...

Omenta

The omentum are specialized folds of peritoneum that enclose nerves,

blood vessel The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide awa ...

lymph channel The lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels (tubes), structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph ves ...

s, fatty tissue, and connective tissue. There are two omenta. First, is the greater omentum that hangs off of the transverse colon and greater curvature of the stomach. The other is the lesser omentum that extends between the stomach and the

Clinical significance

Ascites

When fluid collects in the abdominal cavity, this condition is called ascites. This is usually not noticeable until enough fluid has collected to distend the abdomen. The collection of fluid will cause pressure on the viscera,

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated ...

s, and thoracic cavity. Treatment is directed at the cause of the fluid accumulation. One method is to decrease the

portal vein The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approx ...

pressure, especially useful in treating

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue rep ...

Chylous ascites Ascites is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdominal size, increased weight, ab ...

heals best if the lymphatic vessel involved is closed.

Heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

can cause recurring ascites.

Inflammation

Another disorder is called peritonitis which usually accompanies inflammatory processes elsewhere. It can be caused by damage to an organ, or from a contusion to the abdominal wall from the outside or by surgery. It may be brought in by the bloodstream or the lymphatic system. The most common origin is the gastrointestinal tract. Peritonitis can be

acute Acute may refer to: Science and technology * Acute angle ** Acute triangle ** Acute, a leaf shape in the glossary of leaf morphology * Acute (medicine), a disease that it is of short duration and of recent onset. ** Acute toxicity, the adverse ef ...

or chronic, generalized or localized, and may have one origin or multiple origins. The omenta can help control the spread of infection; however without treatment, the infection will spread throughout the cavity. An

abscess An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends ...

may also form as a secondary reaction to an infection.

Antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

s have become an important tool in fighting abscesses; however, external drainage is usually required also.

References

External links

{{Authority control Abdomen