9 Regions of the Abdomen: Anatomical Guide & Clinical Relevance

The abdomen is divided into nine regions by four imaginary planes: two vertical (midclavicular lines) and two horizontal (transpyloric/ subcostal and transtubercular/ intertubercular). This grid localizes organs, pain, and pathology.

Region	Location	Key Organs/Structures	Clinical Notes
Right Hypochondriac (RUQ)	Under right ribs	Liver, gallbladder, right kidney, hepatic flexure of colon	Gallstones, hepatitis, liver abscess
Epigastric	Upper midline	Stomach, liver (left lobe), pancreas, duodenum, adrenal glands	Gastritis, pancreatitis, peptic ulcer, MI referral
Left Hypochondriac (LUQ)	Under left ribs	Spleen, stomach (fundus), left kidney, splenic flexure of colon	Splenomegaly, gastritis, kidney stones
Right Lumbar (RLQ)	Right flank	Right kidney, ascending colon	Pyelonephritis, kidney stones, colon pathology
Umbilical	Around navel	Small intestine (jejunum/ileum), transverse colon, aorta	Early appendicitis, SBO, aortic aneurysm
Left Lumbar (LLQ)	Left flank	Left kidney, descending colon	Diverticulitis, kidney stones, colon cancer
Right Iliac (Inguinal) (RLQ)	Right lower quadrant	Appendix, cecum, right ovary/fallopian tube, ureter	Appendicitis, ovarian cyst, ectopic pregnancy
Hypogastric (Suprapubic)	Lower midline	Bladder, uterus/prostate, rectum	UTI, cystitis, pregnancy, prostatitis
Left Iliac (Inguinal) (LLQ)	Left lower quadrant	Sigmoid colon, left ovary/fallopian tube, ureter	Diverticulitis, ovarian cyst, ectopic pregnancy

Four-Quadrant Alternative

Clinically, the four-quadrant system (RUQ, LUQ, RLQ, LLQ) divided by median and transumbilical planes is often used for rapid assessment. The nine-region system offers greater precision for anatomical study and surgical planning.

Tip: "Hypochondriac" = below cartilage (ribs); "Lumbar" = loin/flank; "Iliac/Inguinal" = groin; "Epigastric" = upon stomach; "Hypogastric" = below stomach.