The human abdomen is divided into quadrants and regions by anatomists and physicians for the purposes of study, diagnosis, and treatment.

[1][2] The division into four quadrants allows the localisation of pain and tenderness, scars, lumps, and other items of interest, narrowing in on which organs and tissues may be involved.

The nine regions offer more detailed anatomy and are delineated by two vertical and two horizontal lines.

Important organs here are: Nine regions of the abdomen can be marked using two horizontal and two vertical dividing lines.

If abdominal pain or signs of peritonitis are localised in the LLQ, colitis, diverticulitis, ureteral colic or pain due to ovarian cysts or pelvic inflammatory disease may be suspected.

The RUQ may be painful or tender in hepatitis, cholecystitis, and peptic ulcer.

The RLQ, in particular the right inguinal region or right iliac fossa may be painful and tender in conditions such as appendicitis.