abdomen

Source

1. The part of the body that lies between the thorax and the pelvis and encloses the stomach, intestines, liver, spleen, and pancreas. Also called belly.
2. The corresponding region in vertebrates other than mammals.
3. The posterior segment of the body in arthropods.

[Latin abdōmen, belly.]

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A major body division of the vertebrate trunk lying posterior to the thorax; and in mammals, bounded anteriorly by the diaphragm and extending to the pelvis. The diaphragm separates the abdominal or peritoneal cavity from the pleural and pericardial cavities of the thorax. In all pulmonate vertebrates (possessing lungs or lunglike organs) other than mammals, the lungs lie in the same cavity with the abdominal viscera, and this cavity is known as the pleuroperitoneal cavity.

The large coelomic cavity that occupies the abdomen contains the viscera within the peritoneal sac. Connecting sheets of peritoneum from the body wall to the various organs form the mesenteries. Other folds of the peritoneum form the omenta.

The term abdomen is also applied to a similar major body division of arthropods and other animals.

The proper anatomical term for what is known colloquially as the belly, or as the ‘stomach’, especially when localizing an ache or pain. The abdomen is roofed by the diaphragm, which separates it from the thorax (chest). At the front and sides is the abdominal wall, of skin, fat and muscle, and at the back, the spine (vertebral column) ; this whole compartment is the abdominal cavity. ‘Cavity’ suggests an empty space, which it is not. It is completely filled with the abdominal organs: the stomach and intestines; the liver, gall bladder, pancreas, spleen, and kidneys. These are all covered by a thin membrane, continuous with that which also lines the inside of the abdominal wall (peritoneum). This encloses the peritoneal ‘cavity’ that normally contains only a film of fluid. The abdominal cavity and its peritoneal lining are continuous below with those of the pelvis.

— Stuart Judge

See alimentary system; peritoneum; alimentary system.

The portion of the body between the thorax and the pelvis.

Lower part of the trunk between the diaphragm and the pelvis containing soft body tissues, including the stomach, kidneys, liver, and intestines. The shape of a healthy abdomen varies. In children it often protrudes, but if this is too marked it may indicate a disease such as kwashiorkor. In young adults, the abdomen should be slightly in-drawn or only slightly prominent, with the outline of the abdominal muscles visible.

The part of the body between the thorax (chest) and pelvis that encloses the organs of the abdominal cavity; the belly.

The portion of the body between the thorax and the pelvis containing the abdominal cavity. See also abdominal.

• acute a. — an acute intra-abdominal condition of abrupt onset, usually associated with pain due to inflammation, perforation, obstruction, infarction or rupture of abdominal organs, and usually requiring emergency intervention. Called also surgical abdomen.
• gaunt a. — decreased abdominal size.
• surgical a. — see acute abdomen (above).

n.

The temple of the god Stomach, in whose worship, with sacrificial rights, all true men engage. From women this ancient faith commands but a stammering assent. They sometimes minister at the altar in a half-hearted and ineffective way, but true reverence for the one deity that men really adore they know not. If woman had a free hand in the world's marketing the race would become graminivorous.

For the human abdomen, see human abdomen.

"Abdominal" redirects here. For the rapper from Canada, see Abdominal (rapper).

The abdomen in a human and in an ant.

In vertebrates such as mammals the abdomen (belly) constitutes the part of the body between the thorax (chest) and pelvis. The region enclosed by the abdomen is termed the abdominal cavity. In arthropods it is the most distal section of the body which lies behind the thorax or cephalothorax^[1][2].

Contents 1 Vertebrates 1.1 Abdominal organs 2 Invertebrates 3 See also 4 References

Vertebrates

In vertebrates, the abdomen is a large cavity enclosed by the abdominal muscles, ventraly and lateraly, and by the vertebral column dorsally. Lower ribs can also enclose ventral and lateral walls. The abdominal cavity is continuous with the pelvic cavity. It is separated from the thoracic cavity by the diaphragm. Structures such as the aorta, inferior vena cava and esophagus pass through the diaphragm. Both the abdominal and pelvic cavities are lined by a serous membrane known as the parietal peritoneum. This membrane is continuous with the visceral peritoneum lining the organs^[3]. The abdomen in vertebrates contains a number of organs belonging, for instance, to the digestive tract and urinary system.

Abdominal organs

• Digestive tract: Stomach, small intestine, large intestine with cecum and appendix
• Accessory organs of the digestive tract: Liver, gallbladder and pancreas
• Urinary system: Kidneys and ureters
• Other organs: Spleen

Abdominal organs can be highly specialized in some animals. For example the stomach of ruminants (a suborder of mammals) is divided into four chambers - rumen, reticulum, omasum and abomasum.^[4]

Invertebrates

In the worker ant, the abdomen consists of the propodeum fused to the thorax and the metasoma, itself divided into the narrow petiole and bulbous gaster.

The invertebrate abdomen is built up of a series of concave upper plates known as tergites and convex lower plates known as sternites, the whole being held together by a tough yet stretchable membrane.

The abdomen contains the insect's digestive tract and reproductive organs, it consists of eleven segments in most orders of insects though the eleventh segment is absent in the adult of most higher orders. The number of these segments does vary from species to species with the number of segments visible reduced to only seven in the common honeybee. In the Collembola (Springtails) the abdomen has only six segments.

The abdomen is sometimes highly modified. In ants, the first segment of the abdomen is fused to the thorax and called the propodeum. The second segment forms the narrow petiole. Some ants have an additional postpetiole segment, and the remaining segments form the bulbous gaster.[1] The petiole and gaster (abdominal segments 2 and onward) are collectively called the metasoma.

Unlike other Arthropods, insects possess no legs on the abdomen in adult form, though the Protura do have rudimentary leg-like appendages on the first three abdominal segments, and Archaeognatha possess small, articulated "styli" which are sometimes considered to be rudimentary appendages. Many larval insects including the Lepidoptera and the Symphyta (Sawflies) have fleshy appendages called prolegs on their abdominal segments (as well as their more familiar thoracic legs), which allow them to grip onto the edges of plant leaves as they walk around.

See also

• Human abdomen
• Opisthosoma
• Metasoma
• Abdominal trauma
• Abdominal fat

References

1. ^ Abdomen. (n.d.). Dictionary.com Unabridged (v 1.1). URL: http://dictionary.reference.com/browse/abdomen [Accessed: 22 Oct 2007]
2. ^ Abdomen. Dictionary.com. The American Heritage Dictionary of the English Language, 4th Edition. URL: http://dictionary.reference.com/browse/abdomen [Accessed: 22 October 2007].
3. ^ Peritoneum. The Veterinary Dictionary. Elsevier, 2007. http://www.answers.com/topic/peritoneum [Accessed: 22 Oct 2007)
4. ^ "Ruminant." The Veterinary Dictionary. Elsevier, 2007. http://www.answers.com/topic/ruminant [Accessed: 22 Oct 2007].

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Dansk (Danish)
n. - underliv, bug, mave

Nederlands (Dutch)
(onder)buik, achterlijf (van insect), ,

Français (French)
n. - (Méd) abdomen, bas-ventre

Deutsch (German)
n. - Unterleib, Bauch

Ελληνική (Greek)
n. - κοιλιά

Italiano (Italian)
basso ventre, addome

Português (Portuguese)
n. - abdome (m) (Anat.)

Русский (Russian)
живот, брюшная полость, брюшко

Español (Spanish)
n. - abdomen, vientre

Svenska (Swedish)
n. - buk

中文（简体）(Chinese (Simplified))
下腹, 腹部

中文（繁體）(Chinese (Traditional))
n. - 下腹, 腹部

한국어 (Korean)
n. - 복부

日本語 (Japanese)
n. - 腹部

العربيه (Arabic)
‏(الاسم) بطن : قسم من جسم الإنسان أسفل الصدر ويحتوي على المعده والأمعاء‏

עברית (Hebrew)
n. - ‮בטן‬

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