Since there are so many organs in the abdominal cavity, it is probably easiest to think of your differential in terms of abdominal quadrants/areas. Below is a list and figure showing some common abdominal diagnoses relative to the abdominal regions.
However, keep in mind that these diagnoses are not confined to just these regions. For example, diverticulitis most commonly presents as left lower quadrant pain, but sometimes can cause pain on the right lower quadrant.
This list and figure are just starting points for you to understand the most common abdominal pathologies and where they usually present.
- Abdominal Pain:
- Right upper quadrant: cholelithiasis, hepatitis, evaluation for free fluid, kidney stones (also flank pain)
- Right lower quadrant: appendicitis, intussusception, psoas abscess, inguinal hernia
- Left upper quadrant: splenomegaly, evaluation for free fluid, kidney stones (also flank pain)
- Left lower quadrant: diverticulitis, small bowel obstruction, inguinal hernia
- Epigastric: AAA, pancreatitis, SBO (can also be generalized)
- Pelvic: urinary retention, pregnancy, ectopic pregnancy, pelvic mass, evaluation for free fluid
- Testicular: torsion, epididymitis, hydrocele.
- Abdominal Trauma: Evaluation for abdominal free fluid (hemoperitoneum)

In this post, we will cover the most common Point of Care Ultrasound (POCUS) applications of abdominal ultrasound including: Hepatobiliary, Spleen, Appendix, Free Fluid Detection, Bowel Emergencies (small bowel obstruction/pneumoperitoneum), and Pediatric specific abdominal applications (pyloric stenosis, intussusception)