What are the 9 abdominopelvic regions and where are they located?

When a patient presents with abdominal pain, determining the location of the pain provides a useful starting point that guides further work for the clinician. Let’s take a closer look at the abdominal divisions which form a vital part of the physical exam.

The abdominopelvic cavity can be subdivided into four quadrants and nine regions. The quadrants represent locations; they are formed by a vertical imaginary line drawn through the linea alba from the xiphoid process of the sternum to the pubic symphysis and a horizontal line passing through the umbilicus. This divides the abdomen into four quadrants:

• Right upper
• Right lower
• Left upper
• Left lower

The nine regions are smaller than the four abdominopelvic quadrants: The dividing planes are based on horizontal and vertical lines, drawn between palpable bony points.

The horizontal planes include the subcostal plane, which joins the most inferior parts of the rib cage – usually the 10th costal cartilage – and the transtubercular plane, which joins the two tubercles of the iliac crests.

The two vertical planes are similar on each side and follow a line joining the mid-clavicular point to the mid-inguinal point.

These planes divide the abdomen into nine regions:

• Right hypochondriac
• Right lumbar (or flank)
• Right illiac
• Epigastric
• Umbilical
• Hypogastric (or pubic)
• Left hypochondriac
• Left lumbar (or flank)
• Left illiac

The abdominal divisions should be used in conjunction with other diagnostic approaches in order to accurately diagnose a patient’s condition. For instance, a right lower quadrant pain suggests acute appendicitis. However, an optimal approach to diagnose the basis for abdominal pain should rely on the likelihood of disease, complaints, and other features of patient history, findings on physical examination, laboratory tests, and imaging studies.

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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 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, 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 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. 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[edit]

Diagram showing which organs (or parts of organs) are in each quadrant of the abdomen

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 left upper quadrant (LUQ) extends from the median plane to the left of the patient, and from the umbilical plane to the left ribcage. The equivalent term for animals is left anterior quadrant. Important organs here are:

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:

The right lower quadrant (RLQ) extends from the median plane to the right of the patient, and from the umbilical plane to the right inguinal ligament. The equivalent term for animals is right posterior quadrant. Important organs here are:

Regions[edit]

Regions shown on left in side-by-side comparison with quadrants.

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 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 connecting the tubercles of the pelvis.[3][4]

The three main centrally positioned regions are the epigastric region, the umbilical region, and the hypogastric region also known as the pubic 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.[3][4]

("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[edit]

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. Examples of tumors in the left lower quadrant include colon cancer and ovarian tumor.

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

Where is the Abdominopelvic region located?