What is the part below the chest called?: Understanding the Abdomen

October 2, 2025 •

3 min read

Did you know that the abdomen, the part below the chest, houses most of your body's digestive organs? Separated from the chest by the diaphragm, this vital region contains a complex network of systems critical for digestion, waste filtration, and overall health.

Quick Summary

The part below the chest is the abdomen, containing vital organs like the stomach, liver, and intestines, enclosed by protective abdominal muscles. It is separated from the chest by the diaphragm, and its health is fundamental to bodily functions.

Key Points

The Abdomen is Below the Chest: The abdomen is the anatomical region of the torso situated between the diaphragm and the pelvis.
Diaphragm is the Separator: A dome-shaped muscle called the diaphragm creates the border between the thoracic (chest) and abdominal cavities.
Home to Vital Organs: The abdomen houses most of the digestive organs (stomach, intestines, liver, etc.), as well as the kidneys, spleen, and adrenal glands.
Protected by Strong Muscles: The abdominal wall is composed of layered muscles, including the rectus abdominis and obliques, which protect organs and assist with movement and posture.
Divisions for Diagnosis: For clinical purposes, the abdomen is divided into four quadrants or nine regions to help pinpoint the location of organs and the source of pain.
Pain Can Be a Warning Sign: Abdominal pain can result from many different conditions affecting the organs, muscles, or structural components within this complex region.

The Abdominal Cavity: An Overview

The abdomen is the large, central body cavity situated between the thoracic cavity (chest) and the pelvic cavity. Its superior boundary is the diaphragm, a large dome-shaped muscle essential for breathing that separates the chest and abdominal contents. Inferiorly, the abdomen opens into the pelvis. This region is enclosed by a wall of muscles that provide protection and support. Within the abdomen are numerous organs responsible for digestion and metabolism.

Vital Organs Within the Abdomen

The abdominal cavity contains a variety of vital organs, including those from the digestive, urinary, and immune systems.

Digestive System Organs

Key digestive organs in the abdomen include the stomach, small intestine, large intestine (colon), liver, gallbladder, and pancreas. These organs are responsible for processing food, absorbing nutrients, and eliminating waste.

Urinary and Immune System Organs

Within the abdomen, you'll find the kidneys and ureters (part of the urinary system), the spleen (part of the immune system), and the adrenal glands. These organs play crucial roles in filtering waste, fighting infection, and hormone production.

Reproductive Organs

In females, reproductive organs like the uterus, ovaries, and fallopian tubes are located in the lower abdomen.

Muscles of the Abdominal Wall

The abdominal wall is comprised of several muscle layers that protect internal organs, support the body's core, and aid in movement. These muscles include:

Rectus Abdominis: The vertical muscles often called the "six-pack".
External Oblique Muscles: Located on the sides, assisting in twisting motions.
Internal Oblique Muscles: Situated beneath the external obliques, also involved in trunk rotation.
Transversus Abdominis: The deepest layer, important for core stability.

Clinical Divisions of the Abdomen

Medical professionals divide the abdomen into regions to help pinpoint organ locations and diagnose issues.

Four Quadrants System

The abdomen is often divided into four quadrants using lines intersecting at the navel. These are the Right Upper Quadrant (RUQ), Left Upper Quadrant (LUQ), Right Lower Quadrant (RLQ), and Left Lower Quadrant (LLQ). Each quadrant contains specific organs.

Nine Regions System

A more detailed division uses nine regions for greater precision in locating structures.

Comparison of Abdominal Quadrants


Quadrant	Key Organs	Associated Pain (Examples)
Right Upper Quadrant	Liver, Gallbladder, Duodenum, Right Kidney	Gallstones, Liver inflammation, Duodenal ulcers
Left Upper Quadrant	Stomach, Spleen, Pancreas, Left Kidney	Gastritis, Spleen issues, Pancreatitis
Right Lower Quadrant	Appendix, Cecum, Right Ovary (females)	Appendicitis, Kidney stones, Ovarian issues
Left Lower Quadrant	Descending & Sigmoid Colon, Left Ovary (females)	Diverticulitis, Constipation, Ovarian issues

Common Abdominal Health Concerns

The abdomen can be affected by various health issues, leading to symptoms like pain, bloating, or swelling.

Digestive Issues

Conditions like gastritis (stomach inflammation), appendicitis (appendix inflammation), pancreatitis (pancreas inflammation), and GERD (acid reflux) are common causes of abdominal discomfort.

Structural and Muscular Problems

Hernias, where tissue bulges through a weak spot in the abdominal wall, and muscle strains are also frequent issues.

Other Conditions

Kidney stones and an enlarged spleen are other potential sources of abdominal pain or discomfort.

Conclusion

The abdomen is a vital and complex area below the chest, housing crucial organs for digestion, filtration, and other bodily functions. Its muscular wall provides protection and support. Understanding its anatomy and recognizing symptoms of common issues are important for maintaining health. If you experience persistent or severe abdominal pain, it is essential to seek medical advice for proper diagnosis and treatment.

For more detailed information on abdominal anatomy, Kenhub provides in-depth resources on the abdomen and pelvis.

Frequently Asked Questions

The diaphragm, a large, thin, dome-shaped muscle, serves as the physical separator between the chest (thoracic cavity) and the abdomen (abdominal cavity).

The abdomen contains numerous vital organs, including the stomach, liver, gallbladder, pancreas, small and large intestines, kidneys, spleen, and adrenal glands.

The "six-pack" muscles are the rectus abdominis, which are a pair of vertical muscles that run down the front of the abdomen.

The abdomen is divided into quadrants (Right Upper, Left Upper, Right Lower, and Left Lower) for clinical assessment and localization, helping medical professionals to describe organ locations and the source of a patient's symptoms.

Yes, while minor issues like gas or muscle strain are common, persistent or severe abdominal pain can be a sign of a more serious underlying condition and may require medical attention.

A hernia occurs when a part of an organ or tissue bulges through a weak area in the muscle wall surrounding it. Many types occur in the abdomen, such as an inguinal hernia or a hiatal hernia, where the stomach bulges through the diaphragm.

Abdominal muscles provide protection for internal organs, offer postural support, and assist with a variety of movements including bending the trunk, forced exhalation, and increasing intra-abdominal pressure during activities like coughing or urination.