The human abdomen is divided into regions by anatomists and physicians for purposes of study, diagnosis, and therapy.  In the four-region scheme, four quadrants allow localisation of pain and tenderness, scars, lumps, and other items of interest, narrowing in on which organs 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, as follows.
The term is not used in comparative anatomy, since most other animals do not stand erect. The equivalent term for animals is left posterior quadrant.
The equivalent term for animals is 'left anterior quadrant'.
The equivalent term for animals is 'right anterior quadrant'.
The equivalent term for animals is 'right posterior quadrant'.
- Left lobe of liver
- Body of pancreas
- Left kidney and adrenal gland
- Splenic flexure of colon
- Parts of transverse and descending colon
- Gall bladder with biliary tree
- Head of pancreas
- Right kidney and adrenal gland
- Hepatic flexure of colon
In the LLQ if abdominal pain or signs of peritonitis are localised, colitis, diverticulitis, ureteral colic or pain due to ovarian cysts or pelvic inflammatory disease, may be suspected. Examples of tumours in the left lower quadrant include colon cancer or ovarian tumour.
The RLQ may be painful and/or tender in such conditions as appendicitis.
- Gastroenteritis, mesenteric adenitis, Meckel's diverticulitis, intussusception, Henoch-Schönlein purpura, lobar pneumonia
- regional enteritis, renal colic, perforated peptic ulcer, testicular torsion, rectus sheath hematoma, pelvic inflammatory disease, ectopic pregnancy, endometriosis, torsion/rupture of ovarian cyst, appendicitis
- diverticulitis, intestinal obstruction, colonic carcinoma, mesenteric ischemia, leaking aortic aneurysm.