What Are the Four Abdominal Quadrants and What Organs Are in Each?

The four abdominal quadrants are defined by two imaginary lines that intersect at the umbilicus: a vertical midline (median plane) and a horizontal transumbilical plane. These lines divide the abdomen into the right upper quadrant (RUQ), left upper quadrant (LUQ), right lower quadrant (RLQ), and left lower quadrant (LLQ). Clinicians use this system to quickly communicate where a patient is experiencing pain, tenderness, or masses, and to narrow down the differential diagnosis based on which organs occupy that region. For anatomy students, knowing which organs sit in each quadrant is a high-yield skill tested on both written exams and practicals.

The RUQ contains the liver (right lobe), gallbladder, pylorus of the stomach, duodenum (first three parts), head of the pancreas, right adrenal gland, right kidney (upper pole), hepatic flexure of the colon, and portions of the ascending and transverse colon. The most clinically tested association is RUQ pain with gallbladder pathology — cholecystitis produces tenderness in the RUQ, and Murphy's sign (inspiratory arrest during RUQ palpation) helps confirm the diagnosis. Liver pathology and hepatitis can also produce RUQ discomfort, often with associated jaundice.

The LUQ contains the stomach (body and fundus), spleen, tail of the pancreas, left adrenal gland, left kidney (upper pole), splenic flexure of the colon, and portions of the transverse and descending colon. The spleen is the most commonly injured abdominal organ in blunt trauma, and LUQ pain radiating to the left shoulder (Kehr's sign) can indicate splenic rupture with diaphragmatic irritation. The stomach's position in the LUQ means gastric ulcers often present with epigastric or LUQ pain.

The RLQ contains the appendix and cecum, terminal ileum, right ureter, right ovary and fallopian tube (in females), and right spermatic cord (in males). The appendix is the most clinically significant structure here — appendicitis classically presents with periumbilical pain that migrates to McBurney's point in the RLQ. This is one of the most commonly tested clinical correlations in anatomy. The RLQ is also relevant for ectopic pregnancies and ovarian pathology in female patients.

The LLQ contains the sigmoid colon, descending colon, left ureter, left ovary and fallopian tube (in females), and left spermatic cord (in males). Diverticulitis is the classic LLQ pathology — inflammation of diverticula in the sigmoid colon produces LLQ pain, sometimes called left-sided appendicitis. The sigmoid colon's position makes it the most common site for diverticular disease in Western populations. As with the RLQ, ovarian and ureteral pathology should be considered for LLQ pain.

Draw the four quadrants on a blank page and fill in the organs from memory — this active recall method is far more effective than rereading a list. Pay special attention to the clinical pain patterns: RUQ equals gallbladder and liver, LUQ equals spleen and stomach, RLQ equals appendix, LLQ equals sigmoid colon. These associations show up repeatedly on anatomy exams and clinical vignettes. If you are studying from cadaver images or anatomical models, snap a photo with AnatomyIQ to get instant identification of visible structures and their quadrant locations. This reinforces spatial memory and gives you immediate feedback on structures you might have mislabeled.