Human abdomen

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Human abdomen

The human abdomen (from the Latin

Latin

Latin is an Italic language, historically spoken in Latium and Ancient Rome. Through the Military history of the Roman Empire, Latin spread throughout the Mediterranean and a large part of Europe....
word meaning "belly") is the part of the body between the pelvis

Pelvis

The pelvis or pelvic girdle is the irregular bone structure located at the base of the spine . In the adult human, it is formed by the sacrum and the coccyx, the caudal part of the axial skeleton, and a pair of hip bones, part of the appendicular skeleton or human leg....
and the thorax

Chest

The chest is a part of the anatomy of humans and various other animals sometimes referred to as the thorax....
. Anatomically, the abdomen stretches from the thorax at the thoracic diaphragm

Thoracic diaphragm

In the anatomy of mammals, the thoracic diaphragm is a sheet of muscle extending across the bottom of the ribcage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in Respiration ....
to the pelvis at the pelvic brim

Pelvic brim

The pelvis is divided by an oblique plane passing through the prominence of the sacrum, the Arcuate line and pectineal line s, and the upper margin of the symphysis pubis, into the greater pelvis and the lesser pelvis....
. The pelvic brim stretches from the lumbosacral angle (the intervertebral disk between L5 and S1) to the pubic symphysis

Pubic symphysis

The pubic symphysis is the midline cartilage joint uniting the superior pubic ramus of the left and right pubis . It is located anterior to the urinary bladder and superior to the external genitalia; for females it is above the vulva and for males it is above the penis....
and is the edge of the pelvic inlet

Pelvic inlet

The superior circumference of the lesser pelvis forms the brim of the pelvis, the included space being called the superior aperture or pelvic inlet....
. The space above this inlet and under the thoracic diaphragm is termed the abdominal cavity

Abdominal cavity

The abdominal cavity is the body cavity of the human body that holds the bulk of the viscus and which is located below the thoracic cavity, and above the pelvic cavity....
.

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The human abdomen (from the Latin

Latin

Pelvis

Chest

The chest is a part of the anatomy of humans and various other animals sometimes referred to as the thorax....
. Anatomically, the abdomen stretches from the thorax at the thoracic diaphragm

Thoracic diaphragm

Pelvic brim

Pubic symphysis

Pelvic inlet

Abdominal cavity

The abdominal cavity is the body cavity of the human body that holds the bulk of the viscus and which is located below the thoracic cavity, and above the pelvic cavity....
. The boundary of the abdominal cavity is the abdominal wall in the front and the peritoneal surface at the rear.

Functionally, the human abdomen is where most of the alimentary tract is placed and so most of the absorption and digestion of food occurs here. The alimentary tract in the abdomen consists of the lower esophagus

Esophagus

The esophagus or oesophagus , sometimes known as the gullet, is an Organ in vertebrates which consists of a Muscle tube through which food passes from the pharynx to the stomach....
, the stomach

Stomach

In most mammals, the stomach is a hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication....
, the duodenum

Duodenum

The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum....
, the jejunum

Jejunum

The jejunum is the middle section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms middle intestine or mid-gut may be used instead of jejunum....
, ileum

Ileum

The ileum is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum....
, the cecum

Cecum

The cecum or caecum is a pouch connected to the ascending colon of the large intestine and the ileum. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine....
and the appendix

Vermiform appendix

In human anatomy, the appendix is a blind ended tube connected to the cecum , from which it develops embryologically. The cecum is a pouch-like structure of the Colon ....
, the ascending

Ascending colon

The ascending colon is smaller in caliber than the cecum, with which it is continuous.It passes upward, from its commencement at the cecum, opposite the colic valve, to the under surface of the right lobe of the liver, on the right of the gall-bladderyeo, where it is lodged in a shallow depression, the colic impression; here it bends abrupt...
, transverse

Transverse colon

The transverse colon the longest and most movable part of the Colon , passes with a downward convexity from the right hypochondrium region across the abdomen, opposite the confines of the epigastric and umbilical zones, into the left hypochondrium region, where it curves sharply on itself beneath the lower end of the spleen, forming the splen...
and descending colon

Descending colon

The descending colon of humans passes downward through the left hypochondrium and lumbar regions, along the lateral border of the left kidney....
s, the sigmoid colon

Sigmoid colon

The sigmoid colon forms a loop which averages about 40 cm. in length, and normally lies within the pelvis, but on account of its freedom of movement it is liable to be displaced into the abdominal cavity....
and the rectum

Rectum

The rectum is the final straight portion of the large intestine in some mammals, and the Gastrointestinal tract in others, terminating in the anus....
. Other vital organs inside the abdomen include the liver

Liver

The liver is a vital organ present in vertebrates and some other animals; it has a wide range of functions, a few of which are detoxification, protein synthesis, and production of biochemicals necessary for digestion....
, the kidneys, the pancreas

Pancreas

The pancreas is a gland Organ in the digestive system and endocrine system of vertebrates. It is both an endocrine gland , as well as an exocrine gland, secreting pancreatic juice containing Digestion enzymes that pass to the small intestine....
and the spleen

Spleen

The spleen is an organ found in all vertebrate animals. In humans, the spleen is located in the abdomen of the body, where it functions in the destruction of redundant red blood cells, and holds a reservoir of blood....
.

The abdominal wall is split into the posterior (back), lateral (sides) and anterior (front) walls.

Muscles of the abdominal wall

Muscle	Origin and insertion >- \| The obliquus externus (external oblique) muscle MUSCLE MUSCLE is public domain, multiple sequence alignment software for protein and nucleotide sequences.MUSCLE is integrated into UGENE bioinformatics tool as a plugin.... is the outermost muscle covering the side of the abdomen. It is broad, flat, and irregularly quadrilateral.	It originates on the lower eight rib Rib In vertebrate anatomy, ribs are the long curved bones which form the ribcage. In most vertebrates, ribs surround the chest and protect the lungs, heart, and other internal Organ s of the thorax.... s, and then curves down and forward towards its insertion on the outer anterior crest of the ilium Ilium (bone) The ilium is the uppermost and largest bone of the pelvis, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium.... and (via the sheath of the rectus abdominis muscle) the midline linea alba Linea alba The linea alba is a fibrous structure that runs down the midline of the abdomen in humans and other vertebrates. The name means white line and the linea alba is indeed white, being composed mostly of collagen connective tissue.... . \|- \| The obliquus internus (internal oblique) muscle is triangularly shaped and is smaller and thinner than the external oblique muscle that overlies it.	It originates from Poupart's ligament/inguinal ligament Inguinal ligament The inguinal ligament is a band running from the pubic tubercle to the anterior superior iliac spine. Its anatomy is very important for operating on hernia patients.... and the inner anterior crest of the ilium. The lower two-thirds of it insert, in common with fibers of the external oblique and the underlying transversus abdominis, into the linea alba Linea alba The linea alba is a fibrous structure that runs down the midline of the abdomen in humans and other vertebrates. The name means white line and the linea alba is indeed white, being composed mostly of collagen connective tissue.... . The upper third inserts into the lower six ribs. \|- \| The transversus abdominis muscle is flat and triangular, with its fibers running horizontally. It lies between the internal oblique and the underlying transversalis fascia.	It originates from Poupart's ligament, the inner lip of the ilium, the lumbar fascia and the inner surface of the cartilage Cartilage Cartilage is a type of dense connective tissue. It is composed of specialized cells called chondrocyte that produce a large amount of extracellular matrix composed of collagen fibers, abundant ground substance rich in proteoglycan, and elastin fibers.... s of the six lower ribs. It inserts into the linea alba behind the rectus abdominis. \|- \| The rectus abdominis muscle Rectus abdominis muscle The rectus abdominis muscle is a paired muscle running vertically on each side of the anterior wall of the human abdomen . There are two parallel muscles, separated by a midline band of connective tissue called the Linea_alba_%28abdomen%29 .... s are long and flat. The muscle is crossed by three tendinous Tendon A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension . Tendons are similar to ligaments except that ligaments join one bone to another.... intersections called the linae transversae. The rectus abdominis is enclosed in a thick sheath formed, as described above, by fibers from each of the three muscles of the lateral abdominal wall.	They originate at the pubic bone, run up the abdomen on either side of the linea alba, and insert into the cartilages of the fifth, sixth, and seventh ribs. \|- \| The pyramidalis muscle Pyramidalis muscle The pyramidalis is a small and triangular muscle, anterior to the Rectus abdominis, and contained in the rectus sheath.... is small and triangular. It is located in the lower abdomen in front of the rectus abdominis.	It originates at the pubic bone and is inserted into the linea alba half way up to the umbilicus Umbilicus Umbilicus may refer to:*Umbilicus , a feature of gastropod, Nautilus and Ammonite shell anatomy*Navel, a synonym for the navel or belly button.... .

Abdominal organs

The abdomen contains most of the tubelike organs of the digestive tract, as well as several solid organs. Hollow abdominal organs include the stomach

Stomach

In most mammals, the stomach is a hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication....
, the small intestine

Small intestine

In vertebrates, including mammals, reptiles, birds, and bony fish, the small intestine is the part of the gastrointestinal tract following the stomach, and is where the vast majority of digestion takes place....
, and the colon

Colon (anatomy)

The colon is the last portion of the digestive system in most vertebrates; it extracts water and salt from feces before they are defecation from the body....
with its attached appendix

Vermiform appendix

In human anatomy, the appendix is a blind ended tube connected to the cecum , from which it develops embryologically. The cecum is a pouch-like structure of the Colon ....
. Organs such as the liver

Liver

Gallbladder

The gallbladder is a small non-vital Organ which aids in the digestive process and concentrates bile produced in the liver....
, and the pancreas

Pancreas

Spleen

Kidney

The kidneys are Organ that have numerous biological roles. Their primary role is to maintain the homeostasis balance of bodily fluids by filtering and secreting Metabolomics#Metabolitess and minerals from the blood and excreting them, along with water , as urine....
s, and adrenal gland

Adrenal gland

In mammals, the adrenal glands are the star-shaped endocrine glands that sit on top of the kidneys; their name indicates that position . They are chiefly responsible for regulating the stress response through the biosynthesis of corticosteroids and catecholamines, including cortisol and adrenaline, respectively....
s also lie within the abdomen, along with many blood vessels including the aorta

Aorta

The aorta is the largest artery in the human body, originating from the left ventricle of the heart and bringing oxygenated blood to all parts of the body in the systemic circulation....
and inferior vena cava

Venae cavae

The superior and inferior vena cava are collectively called the venae cavae. They are the veins that return deoxygenated blood from the body into the heart....
. Anatomists may consider the urinary bladder

Urinary bladder

In anatomy, the urinary bladder is a solid, muscle, and distensible organ that sits on the pelvic floor in mammals. It is the organ that collects urine excreted by the kidneys prior to disposal by urination....
, uterus

Uterus

The uterus is a major female hormone-responsive reproductive sex organ of most mammals, including humans. It is within the uterus that the fetus develops during gestation....
, fallopian tube

Fallopian tube

The Fallopian tubes, named after Gabriel Fallopius , also known as oviducts, uterine tubes, and salpinges are two very fine tubes lined with cilia epithelia, leading from the ovaries of female mammals into the uterus....
s, and ovaries

Ovary

The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in females are homology to testicle in males, in that they are both gonads and endocrine glands....
as either abdominal organs or as pelvic organs. Finally, the abdomen contains an extensive membrane called the peritoneum

Peritoneum

In higher vertebrates, the peritoneum is the serous membrane that forms the lining of the abdomen — it covers most of the intra-abdominal organs....
. A fold of peritoneum may completely cover certain organs, whereas it may cover only one side of organs that usually lie closer to the abdominal wall. Anatomists call the latter type of organs retroperitoneal.

Surface landmarks of the anterior abdomen

In the mid-line a slight furrow extends from the ensiform cartilage/xiphoid process

Xiphoid process

The xiphoid Process , also known as the xiphisternum is a small Cartilage extension to the lower part of the sternum which is usually Ossification in the adult human....
above to the symphysis pubis below, representing the linea alba

Linea alba

The linea alba is a fibrous structure that runs down the midline of the abdomen in humans and other vertebrates. The name means white line and the linea alba is indeed white, being composed mostly of collagen connective tissue....
in the abdominal wall. At about its midpoint sits the umbilicus or navel. On each side of it the broad recti muscles stand out in muscular people. The outline of these muscles is interrupted by three or more transverse depressions indicating the lineae transversae. There is usually one about the ensiform cartilage, one at the umbilicus

Umbilicus

Umbilicus may refer to:*Umbilicus , a feature of gastropod, Nautilus and Ammonite shell anatomy*Navel, a synonym for the navel or belly button....
, and one between. It is the combination of the linea alba and the linea transversae which form the abdominal "six-pack" sought after by many people.

The upper lateral limit of the abdomen is the subcostal margin formed by the cartilages of the false ribs (8, 9, 10) joining one another. The lower lateral limit is the anterior crest of the ilium

Ilium (bone)

The ilium is the uppermost and largest bone of the pelvis, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium....
and Poupart's ligament, which runs from the anterior superior spine of the ilium to the spine of the pubis

Pubis (bone)

The android pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis....
. These lower limits are marked by visible grooves. Just above the pubic spines on either side are the external abdominal rings, which are openings in the muscular wall of the abdomen through which the spermatic cord

Spermatic cord

The spermatic cord is the name given to the cord-like structure in males formed by the vas deferens and surrounding tissue that run from the abdomen down to each testicle....
emerges in the male, and through which an inguinal hernia

Inguinal hernia

Inguinal hernias are protrusions of abdominal cavity contents through the inguinal canal. They are very common and their repair is one of the most frequently performed surgery operations....
may rupture.

One method by which the location of the abdominal contents can be appreciated is to draw three horizontal and two vertical lines.

Horizontal lines

The highest of the former is the transpyloric line of C. Addison, which is situated half-way between the suprasternal notch
Suprasternal notch

The suprasternal notch , also known as the jugular notch, is part of human anatomy. It is a large, visible dip....
and the top of the symphysis pubis, and often cuts the pyloric opening of the stomach an inch to the right of the mid-line. The hilum
Hilum

A hilum is a depression or pit where structures are attached.* In human anatomy, the hilum is part of an Organ where structures such as blood vessels and nerves enter....
of each kidney
Kidney

The kidneys are Organ that have numerous biological roles. Their primary role is to maintain the homeostasis balance of bodily fluids by filtering and secreting Metabolomics#Metabolitess and minerals from the blood and excreting them, along with water , as urine....
is a little below it, while its left end approximately touches the lower limit of the spleen
Spleen

The spleen is an organ found in all vertebrate animals. In humans, the spleen is located in the abdomen of the body, where it functions in the destruction of redundant red blood cells, and holds a reservoir of blood....
. It corresponds to the first lumbar vertebra behind.

The second line is the subcostal line, drawn from the lowest point of the subcostal arch (tenth rib
Tenth rib

The tenth rib has only a single articular facet on its Head of rib.See also* False ribsAdditional imagesExternal links...
). It corresponds to the upper part of the third lumbar vertebra, and it is an inch or so above the umbilicus. It indicates roughly the transverse colon
Transverse colon

The transverse colon the longest and most movable part of the Colon , passes with a downward convexity from the right hypochondrium region across the abdomen, opposite the confines of the epigastric and umbilical zones, into the left hypochondrium region, where it curves sharply on itself beneath the lower end of the spleen, forming the splen...
, the lower ends of the kidneys, and the upper limit of the transverse (3rd) part of the duodenum
Duodenum

The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum....
.

The third line is called the intertubercular line, and runs across between the two rough tubercles, which can be felt on the outer lip of the crest of the ilium about two and a half inches (60 mm) from the anterior superior spine. This line corresponds to the body of the fifth lumbar vertebra, and passes through or just above the ileo-caecal valve, where the small intestine
Small intestine

In vertebrates, including mammals, reptiles, birds, and bony fish, the small intestine is the part of the gastrointestinal tract following the stomach, and is where the vast majority of digestion takes place....
joins the large
Large intestine

The large intestine is the last part of the digestive system?the final stage of the alimentary canal?in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass this useless feces from the body....
.

Vertical lines

The two vertical or mid-Poupart lines are drawn from the point midway between the anterior superior spine and the pubic symphysis on each side, vertically upward to the costal margin.

The right one is the most valuable, as the ileo-caecal valve is situated where it cuts the intertubercular line. The orifice of the vermiform appendix
Vermiform appendix

In human anatomy, the appendix is a blind ended tube connected to the cecum , from which it develops embryologically. The cecum is a pouch-like structure of the Colon ....
lies an inch lower, at McBurney's point
McBurney's point

McBurney's point is the name given to the point over the right side of the abdomen that is one-third of the distance from the ASIS to the Navel ....
. In its upper part, the vertical line meets the transpyloric line at the lower margin of the ribs, usually the ninth, and here the gallbladder
Gallbladder

The gallbladder is a small non-vital Organ which aids in the digestive process and concentrates bile produced in the liver....
is situated.

The left mid-Poupart line corresponds in its upper three-quarters to the inner edge of the descending colon
Descending colon

The descending colon of humans passes downward through the left hypochondrium and lumbar regions, along the lateral border of the left kidney....
.

The right subcostal margin corresponds to the lower limit of the liver

Liver

Viscus

In anatomy, a viscus is an internal organ of an animal , in particular an internal organ of the thorax or abdomen. The viscera, when removed from a butchered animal, are known collectively as offal....
.

Regions of the abdomen

9-region scheme

These three horizontal and two vertical lines divide the abdomen into nine "regions." (Note that "hypo" means "below" and "epi" means "above", while "chond" means "cartilage" (in this case, the cartilage of the rib) and "gast" means stomach. The reversal of "left" and "right" is intentional, because the anatomical designations reflect the position on the patient. )

right hypochondriac/hypochondrium Hypochondrium The hypochondrium is the upper part of the abdomen caudal to the lowest ribs of the thorax. The word derives from the Greek term hupokhondros, meaning abdomen, or literally under cartilage....	epigastric/epigastrium Epigastrium The epigastrium is the upper central region of the abdomen. It is located between the costal margins and the subcostal plane.The epigastrium is one of the nine anatomical regions of the abdomen, along with the right and left hypochondrium, right and left lateral regions , right and left inguinal regions , and the umbilical and pubic region...	- \| right lumbar Lumbar In anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm and the sacrum .... /flank Flank Flank may refer to:* Flank, the side of either a horse or a military unit* Flanking maneuver in military tactics* Digital signal#Waveforms in digital systems, when a signal goes high or low it forms an waveform "edge".... /latus Latus (anatomy) The latus is a region of the abdomen between the hypochondrium and inguinal region.In some contexts, it is sometimes called the flank or lumbar region.... /lateral	umbilical Umbilical region The Umbilical Region, in the anatomists' abdominal pelvic 9 region scheme, is the area surrounding the umbilicus . The upper 3 regions from left to right are the left hypochondriac, epigastric, and right hypochondriac regions....	- \| right inguinal/iliac Iliac Iliac can refer to one of the following:* Iliac artery* Ilium * Iliac veinExcess long comment to prevent listing on...	hypogastric Hypogastrium The hypogastrium is an area of the human abdomen residing below the umbilicus.External links... /pubic	left inguinal/iliac

4-region scheme

Another way of dividing the abdomen is by using 4 quadrants:

right upper quadrant (RUQ)	left upper quadrant Left upper quadrant (abdomen) The Left upper quadrant of the human abdomen, often Abbreviation as LUQ, is used to refer to a portion of the abdomen that allows physicians to localise pain and tenderness, scars, lumps and other items of interest.... (LUQ) \|- \| right lower quadrant Right lower quadrant (abdomen) The Right lower quadrant of the human abdomen, often Abbreviation as RLQ, is used to refer to a portion of the abdomen that allows physicians to localise pain and tenderness, scars, lumps and other items of interest.... (RLQ)	left lower quadrant Left lower quadrant (abdomen) The Left lower quadrant of the human abdomen is the area left of the midline and below the umbilicus. The abdomen is divided into quadrants by physicians to localise pain and tenderness, scars, lumps and other items of interest.... (LLQ)

Human abdomen

Muscles of the abdominal wall

Abdominal organs

Surface landmarks of the anterior abdomen

Horizontal lines

Vertical lines

Regions of the abdomen

9-region scheme

4-region scheme

See also