To promote clear communication, for instance, about the location of a patient's abdominal pain or a suspicious mass, anatomists and clinicians typically use imaginary lines to categorize the abdominopelvic cavity into either four quadrants or nine regions to identify organs in the cavity.
The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersects at the patient's umbilicus (navel). The four quadrants are the right upper (RUQ), right lower (RLQ), left upper (LUQ), and left lower quadrants (LLQ). The LUQ houses the stomach, the spleen, the pancreas, and the left parts of the left kidney, liver, colon, and small intestine, whereas the RUQ contains the gallbladder and the right parts of the liver, kidney, stomach, small intestine, and colon. The LLQ has the small intestine, the ureter, and the female reproductive organs. However, the appendix, the cecum, some parts of the ureter, and female reproductive organs are present in the RLQ.
A more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs, one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle (collarbone). This method uses two transverse and two parasagittal planes intersecting like a tic-tac-toe grid on the abdomen. It subdivides nine smaller regions with the centermost umbilical region, with the superiorly located epigastric and inferior hypogastric or pubic region. The umbilicus region is composed of the navel, small intestine, transverse colon, and the bottom of both kidneys. The epigastric region contains the stomach, portions of the liver, the pancreas, the spleen, the duodenum, and the adrenal glands. Lateral to the umbilical, the right lumbar region holds the gallbladder and the ascending colon, whereas the left lumbar region holds the descending colon and the left kidney.
The right hypochondriac region is lateral to the epigastric region and contains the right part of the liver, the right kidney, and gallbladder. The spleen, the left kidney, part of the stomach, the pancreas, and the colon occupy the left hypochondriac region. The hypogastric region includes the bladder, the sigmoid colon, the anus, the uterus, and ovaries in females and the prostate in males. The right and left inguinal or iliac regions are lateral to the hypogastric region. The right iliac region contains the appendix, the right iliac fossa, and the cecum. The left iliac region has the descending and sigmoid colon and the left iliac fossa.
Clinical significance:
The quadrants and regions are used to locate the source of pain and help determine the appropriate treatment. For example, pain in the LUQ is indicative of kidney stones, inflammatory or irritable bowel disease, and ovarian cysts. Pain in the RLQ suggests Crohn's disease, endometriosis, and inguinal hernia, whereas LLQ pain is a symptom of pelvic inflammatory diseases. Pain in the RUQ is common in gastric reflux or pancreatitis, while right iliac pain is generally associated with appendicitis.
This text is adapted from Openstax, Anatomy and Physiology 2e, Section 1.6:Anatomical terminology
