abdomen

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abdomen,

in humans and other vertebrates, portion of the trunk between the diaphragm and lower pelvis. In humans the wall of the abdomen is a muscular structure covered by fascia, fat, and skin. The abdominal cavity is lined with a thin membrane, the peritoneum, which encloses the stomach, intestines, liver, and gall bladder; the pancreas, kidneys, and urinary bladder are located behind the peritoneum. The abdomen of the female also contains the ovaries, fallopian tubes, and uterus. The navel, or umbilicus, an exterior scar on the front of the abdomen, marks the point of attachment of the fetus to the maternal organism before birth. In insects, crustacea, and some other arthropods, the term abdomen refers to the entire rear portion of the body.

Abdomen

 

the part of the body of arthropods behind the thorax. The abdomen is clearly articulated in most arthropods; in spiders and ticks the abdominal rings coalesce. The exoskeleton of each distinct segment of the abdomen usually consists of two half-rings: the dorsal plate (tergite) and abdominal half-ring (sternite). The abdomen is connected to the thorax by either the wide (sessile abdomen) or narrow (pedicellate abdomen) anterior part. Only in higher crustaceans does the abdomen have normally developed extremities. In lower crustaceans, arachnids, and some insects, the abdomen completely lacks extremities. In lower insects (bristle-tails), the extremities of the abdomen are either rudimentary or modified into sexual appendages (at the eighth and ninth segments) or cerci (tail fila; at the 11th segment). Higher insects have only sexual appendages and cerci.


Abdomen

 

the portion of the trunk in man that contains the abdominal cavity and its walls.

The walls of the abdomen are formed by skin, muscles, aponeuroses, and fasciae. The posterior wall includes the spinal column (from the 12th thoracic vertebra to the fifth lumbar vertebra); anteriorly and from the sides at the upper portions of the abdomen, the walls are reinforced by the ribs (from the seventh to the 12th) and, in part, by the sternum.

The linea alba abdominis projects along the middle of the anterior wall. The linea alba, a band 2–3 mm wide (sometimes wider), extending from the xiphoid process of the sternum to the pubic symphysis, is formed by the union of the aponeuroses of the abdominal muscles. The line is broadest in the umbilical region. Above, on the anterior wall, the substernal angle, where the costal arches converge, can be distinguished; below, the iliac crests and inguinal ligaments, which separate the abdomen from the hips, stand out in relief. Two transverse lines, the upper connecting the lower points of the tenth ribs and the lower connecting the anterosuperior spines of the pelvic bones (the most prominent bony processes), are considered to divide the anterior wall of the abdomen into the epigastric, celiac, and hypogastric regions. Two longitudinal lines, coinciding with the outer margins of the rectus abdominis muscles, divide the epigastrium into the right and left subcostal regions and the epigastric region proper, the celiac region into the right and left lateral and umbilical regions, and the hypogastrium into the right and left inguinal and pubic regions. In the inguinal region, the inguinal canals (through which pass the spermatic cords of males and the round ligaments of the uterus in females) extend parallel to the inguinal ligaments on the right and left. The internal and external openings of the inguinal canal, the umbilical region, and lumbar triangle are the weakest places in the abdominal wall. Under unfavorable conditions these regions become the sites of abdominal hernias. The shape of the abdomen varies with physique, age, fat deposits, size of the viscera, and the degree of development and condition of the muscles.

V. V. KUPRIANOV

abdomen

[ab′dōm·ən or ′ab·də‚mən]
(anatomy)
The portion of the vertebrate body between the thorax and the pelvis.
The cavity of this part of the body.
(invertebrate zoology)
The elongate region posterior to the thorax in arthropods.

abdomen

1. the region of the body of a vertebrate that contains the viscera other than the heart and lungs. In mammals it is separated from the thorax by the diaphragm
2. (in arthropods) the posterior part of the body behind the thorax, consisting of up to ten similar segments

Abdomen

(dreams)
Dreaming about any body part is a way to bring the dreamer’s conscious attention to it. When, in your dream, you are feeling pain or discomfort in this area or any other area of the body, consider how well that part of your body is functioning in real life. Being health-conscious is a positive thing and both psychological and physical factors need to be considered. At times our unconscious knows that something is wrong even before we have any symptoms.“Old wives’ tales” tell us that this is a dream of the contrary and that you will have lots of vigor and good health.
References in periodicals archive ?
KEY WORDS: sexual maturity, abdomen looseness, mud crabs, Scylla
This is because unlike their female counterparts that show significant morphological changes in their abdomen shape and size (i.
In present paper, red swamp crayfish, with efficient burrowing activities and coupling propel pattern of abdomen with tail, was selected to study the feasible methods in the visual reconstruction and feature analysis of the surface morphology of living things.
The Hawaiian Ariamnes are generally elongate, though there is some variability in the relative elongation of the abdomen which can be almost triangular in side view (A.
The study showed that when a baby who is not used to sleeping in the prone position is suddenly placed on his or her abdomen, the risk of SIDS skyrockets to 20 times greater than if the baby was placed on his or her back.
The first gene affected the mouth, the second the face, the third the top of the head, the fourth the neck, the fifth the thorax, the sixth the front half of the abdomen, the seventh the rear half of the abdomen, and the eighth various other parts of the abdomen.
Orb weavers are the most noticeable garden spiders because of their large size, enormous webs and the bright, symmetrical patterns on their abdomens.
This temporary abdominal closure (TAC) system enables surgeons to take control early in the management of challenging open abdomens, helping to achieve primary fascial closure.
Brushing flowers with substances from female abdomens tricked moths into reacting as if the bloom had already been visited, report Chad J.
However, the animals lost more fat from their abdomens than from other parts of their bodies.
Researchers believe the same process occurs in humans, but confirmation of this hypothesis remains difficult because people carry, in their trunks and abdomens, only small amounts of brown fat.