The human

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

is divided into quadrants and regions by anatomists and physicians for the purposes of study, diagnosis, and treatment. The division into four quadrants allows the localisation of pain and tenderness, scars, lumps, and other items of interest, narrowing in on which

organs In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a ...

and tissues may be involved. The quadrants are referred to as the left lower quadrant, left upper quadrant, right upper quadrant and right lower quadrant. These terms are not used in

comparative anatomy Comparative anatomy is the study of similarities and differences in the anatomy of different species. It is closely related to evolutionary biology and phylogeny (the evolution of species). The science began in the classical era, continuing in ...

, since most other animals do not stand erect. The left lower quadrant includes the left iliac fossa and half of the flank. The equivalent in other animals is ''left posterior quadrant''. The left upper quadrant extends from the

umbilical plane The transumbilical plane or umbilical plane, one of the transverse planes in human anatomy, is a horizontal line that passes through the abdomen at the level of the navel (or umbilicus). In physical examination, clinicians use the transumbilical p ...

to the left ribcage. This is the ''left anterior quadrant'' in other animals. The right upper quadrant extends from umbilical plane to the right ribcage. The equivalent in other animals is ''right anterior quadrant''. The right lower quadrant extends from the umbilical plane to the right

inguinal ligament The inguinal ligament (), also known as Poupart's ligament or groin ligament, is a band running from the pubic tubercle to the anterior superior iliac spine. It forms the base of the inguinal canal through which an indirect inguinal hernia may de ...

. This in other animals is the ''right posterior quadrant''. The nine regions offer more detailed anatomy and are delineated by two vertical and two horizontal lines.

Quadrants

The left lower quadrant (LLQ) of the human abdomen is the area left of the midline and below the umbilicus. The LLQ includes the left iliac fossa and half of the left flank region. The equivalent term for animals is ''left posterior quadrant''. Important organs here are: *the descending colon and sigmoid colon *the left

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

and fallopian tube *the left

ureter The ureters are tubes made of smooth muscle that propel urine from the kidneys to the urinary bladder. In a human adult, the ureters are usually long and around in diameter. The ureter is lined by urothelial cells, a type of transitional ep ...

The left upper quadrant (LUQ) extends from the median plane to the left of the patient, and from the

to the left ribcage. The equivalent term for animals is ''left anterior quadrant''. Important organs here are: *

Stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...

* Spleen * Left lobe of liver *

Body of 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 endoc ...

*Left kidney 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 which ...

Splenic flexure In the anatomy of the human digestive tract, there are two colic flexures, or curvatures in the transverse colon. The right colic flexure is also known as the hepatic flexure, and the left colic flexure is also known as the splenic flexure. Note ...

of colon * Parts of transverse and descending colon The right upper quadrant (RUQ) extends from the median plane to the right of the patient, and from the umbilical plane to the right ribcage. The equivalent term for animals is ''right anterior quadrant''. Important organs here are: * Liver * Gall bladder with

biliary tree The biliary tract, (biliary tree or biliary system) refers to the liver, gallbladder and bile ducts, and how they work together to make, store and secrete bile. Bile consists of water, electrolytes, bile acids, cholesterol, phospholipids and co ...

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 ...

*Head of

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 ...

*Right kidney and

Hepatic flexure In the anatomy of the human digestive tract, there are two colic flexures, or curvatures in the transverse colon. The right colic flexure is also known as the hepatic flexure, and the left colic flexure is also known as the splenic flexure. Note ...

of colon The right lower quadrant (RLQ) extends from the median plane to the right of the patient, and from the umbilical plane to the right

. The equivalent term for animals is ''right posterior quadrant''. Important organs here are: *

Cecum The cecum or caecum is a pouch within the peritoneum that is considered to be the beginning of the large intestine. It is typically located on the right side of the body (the same side of the body as the appendix, to which it is joined). The w ...

Appendix Appendix, or its plural form appendices, may refer to: __NOTOC__ In documents * Addendum, an addition made to a document by its author after its initial printing or publication * Bibliography, a systematic list of books and other works * Index (pu ...

Ascending colon ''Ascending'' is a science fiction novel by the Canadian writer James Alan Gardner, published in 2001 by HarperCollins Publishers under its various imprints.HarperCollins, Avon, HarperCollins Canada, SFBC/Avon; paperback edition 2001, Eos Books. ...

*Right

and Fallopian tube *Right

Regions

Nine regions of the abdomen can be marked using two horizontal and two vertical dividing lines. The vertical lines are the mid-clavicular lines taken from the mid-point of each

clavicle The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the right ...

. The upper horizontal line is the subcostal line taken from the inferior parts of the lowest costal cartilages. The lower horizontal line is the

intertubercular line A lower transverse plane midway between the upper transverse and the upper border of the pubic symphysis; this is termed the intertubercular plane (or transtubercular), since it practically corresponds to that passing through the iliac tubercles; ...

connecting the tubercles of the pelvis. The three main centrally positioned regions are the

epigastric region In anatomy, the epigastrium (or epigastric region) is the upper central region of the abdomen. It is located between the costal margins and the subcostal plane. Pain may be referred to the epigastrium from damage to structures derived from the f ...

, the

umbilical region The umbilical region, is one of the nine regions of the abdomen. It is the region that surrounds the area around the umbilicus and is placed approximately half way between the xiphoid process and the pubic symphysis. This region of the abdomen c ...

, and the hypogastric region also known as the

pubic In vertebrates, the pubic region ( la, pubis) is the most forward-facing (ventral and anterior) of the three main regions making up the coxal bone. The left and right pubic regions are each made up of three sections, a superior ramus, inferior ...

region. On the sides of the abdomen the other six regions are the left and right hypochondriac regions, on either side of the epigastrium; the left and right lumbar flank regions, on either side of the umbilical region, and the left and right iliac or inguinal regions on either side of the hypogastrium. ("Hypo-" means below; "epi-" means above; "chondron" means cartilage (in this case, the cartilage of the rib) and "gaster" means stomach. The reversal of "left" and "right" is intentional, because the anatomical designations reflect the patient's own right and left.)

Clinical significance

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Common causes of pain in the abdomen include gastroenteritis and irritable bowel syndrome. About 15% of people have a more ...

or signs of peritonitis are localised in the LLQ,

colitis Colitis is swelling or inflammation of the large intestine ( colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases. In a medical context, the label ''colitis'' (without qualification ...

diverticulitis Diverticulitis, specifically colonic diverticulitis, is a gastrointestinal disease characterized by inflammation of abnormal pouches—diverticula—which can develop in the wall of the large intestine. Symptoms typically include lower abdomina ...

ureteral colic Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine ...

or pain due to

ovarian cyst An ovarian cyst is a fluid-filled sac within the ovary. Often they cause no symptoms. Occasionally they may produce bloating, lower abdominal pain, or lower back pain. The majority of cysts are harmless. If the cyst either breaks open or causes ...

s or

pelvic inflammatory disease Pelvic inflammatory disease, also known as pelvic inflammatory disorder (PID), is an infection of the upper part of the female reproductive system, namely the uterus, fallopian tubes, and ovaries, and inside of the pelvis. Often, there may be n ...

may be suspected. Examples of tumors in the left lower quadrant include

colon cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel m ...

and

ovarian tumor Ovarian tumors, or ovarian neoplasms, are tumors arising from the ovary. They can be benign or malignant (ovarian cancer). They consist of mainly solid tissue, while ovarian cysts contain fluid. Histopathologic classification Ovarian tumors are ...

. The LUQ may be painful or tender in the case of intestinal malrotation. The RUQ may be painful or tender in hepatitis,

cholecystitis Cholecystitis is inflammation of the gallbladder. Symptoms include right upper abdominal pain, pain in the right shoulder, nausea, vomiting, and occasionally fever. Often gallbladder attacks (biliary colic) precede acute cholecystitis. The pain l ...

, and peptic ulcer. The RLQ, in particular the right inguinal region or

right iliac fossa The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

may be painful and tender in conditions such as

appendicitis Appendicitis is inflammation of the appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, and decreased appetite. However, approximately 40% of people do not have these typical symptoms. Severe complications of a ru ...

Differential diagnosis

Children * gastroenteritis, mesenteric adenitis, Meckel's diverticulitis, intussusception,

Henoch–Schönlein purpura Henoch–Schönlein purpura (HSP), also known as IgA vasculitis, is a disease of the skin, mucous membranes, and sometimes other organs that most commonly affects children. In the skin, the disease causes palpable purpura (small, raised areas of b ...

lobar pneumonia Lobar pneumonia is a form of pneumonia characterized by inflammatory exudate within the intra-alveolar space resulting in consolidation that affects a large and continuous area of the lobe of a lung. It is one of three anatomic classifications ...

Adults *regional enteritis,

renal colic Renal colic is a type of abdominal pain commonly caused by obstruction of ureter from dislodged kidney stones. The most frequent site of obstruction is the vesico-ureteric junction (VUJ), the narrowest point of the upper urinary tract. Acute ob ...

, perforated peptic ulcer, testicular torsion,

rectus sheath hematoma A rectus sheath hematoma is an accumulation of blood in the sheath of the rectus abdominis muscle. It causes abdominal pain with or without a mass. The hematoma may be caused by either rupture of the epigastric artery or by a muscular tear. Caus ...

ectopic pregnancy Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these symptoms. ...

endometriosis Endometriosis is a disease of the female reproductive system in which cells similar to those in the endometrium, the layer of tissue that normally covers the inside of the uterus, grow outside the uterus. Most often this is on the ovaries, fall ...

, torsion/rupture of

, appendicitis Elderly *

, intestinal obstruction,

colonic carcinoma Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel m ...

, mesenteric ischemia, leaking

aortic aneurysm An aortic aneurysm is an enlargement (dilatation) of the aorta to greater than 1.5 times normal size. They usually cause no symptoms except when ruptured. Occasionally, there may be abdominal, back, or leg pain. The prevalence of abdominal aortic ...

References

{{Superficial abdominopelvic anatomy Abdomen

Quadrants

Regions

Clinical significance

Differential diagnosis

See also

References