The abdomen (commonly called the belly) is the body space between the thorax (chest) and pelvis. The diaphragm forms the upper surface of the abdomen. At the level of the pelvic bones, the abdomen ends and the pelvis begins.
The abdomen contains all the digestive organs, including the stomach, small and large intestines, pancreas, liver, and gallbladder. These organs are held together loosely by connecting tissues (mesentery) that allow them to expand and to slide against each other. The abdomen also contains the kidneys and spleen.
Many important blood vessels travel through the abdomen, including the aorta, inferior vena cava, and dozens of their smaller branches. In the front, the abdomen is protected by a thin, tough layer of tissue called fascia. In front of the fascia are the abdominal muscles and skin. In the rear of the abdomen are the back muscles and spine.
- Peritonitis: Inflammation of the covering of the abdominal structures, causing abdominal wall rigidity and severe pain. Usually, this is due to a ruptured or infected abdominal organ.
- Acute abdomen: A medical phrase doctors use to suggest that peritonitis or some other emergency is present and surgery is likely needed.
- Appendicitis: Inflammation of the appendix, in the lower right colon. Usually, an inflamed appendix must be removed by surgery.
- Cholecystitis: Inflammation of the gallbladder, causing severe right-sided abdominal pain. A gallstone blocking the duct exiting the gallbladder is usually responsible.
- Dyspepsia: The feeling of an upset stomach or indigestion. Dyspepsia can result from benign or more serious conditions.
- Constipation: Having fewer than three bowel movements per week. Diet and exercise may help but many people will need to see their health care providers.
- Gastritis: Inflammation of the stomach, often causing nausea and/or pain. Gastritis can be caused by alcohol, NSAIDs, H. pylori infection, or other factors.
- Peptic ulcer disease: Ulcers are erosions and peptic refers to acid. Peptic ulcers are ulcers in the stomach and duodenum (the first part of the small intestine). The usual cause is either an infection with H. pylori or taking anti-inflammatory medications like ibuprofen.
- Intestinal obstruction: A single area of the small or large intestine can become blocked or the entire intestine may stop working. Vomiting and abdominal distension are symptoms.
- Gastroparesis: The stomach empties slowly due to nerve damage from diabetes or other conditions. Nausea and vomiting are symptoms.
- Pancreatitis: Inflammation of the pancreas. Alcohol and gallstones are the most common causes of pancreatitis. Other causes include drugs and trauma; about 10% to 15% of cases are from unknown causes.
- Hepatitis: Inflammation of the liver, usually due to viral infection. Drugs, alcohol, or immune system problems can also cause hepatitis.
- Cirrhosis: Scarring of the liver caused by chronic inflammation. Heavy drinking or chronic hepatitis are the most common causes.
- Ascites: Abdominal fluid buildup often caused by cirrhosis. Ascites may cause the abdomen to protrude impressively.
- Abdominal hernia: A weakening or gap in the abdominal fascia allows a section of the intestine to protrude.
- Abdominal distension: Swelling of the abdomen, usually due to an increased amount of intestinal gas.
- Abdominal aortic aneurysm: A weakening of the aorta's wall creates a balloon-like expansion of the vessel that grows over years. If abdominal aortic aneurysms grow large enough, they may burst.
- Physical examination: By listening with a stethoscope, pressing, and tapping on the abdomen, a doctor gathers information that helps diagnose abdominal problems.
- Upper endoscopy (esophagogastroduodenoscopy or EGD): A flexible tube with a camera on its end (endoscope) is inserted through the mouth. The endoscope allows examination of the stomach and duodenum (small intestine).
- Lower endoscopy (colonoscopy): An endoscope is advanced through the anus into the rectum and colon. Colonoscopy can help identify problems in these areas, such as cancer or bleeding.
- Abdominal X-ray: A plain X-ray of the abdomen can help see the organs and conditions in the belly including intestinal obstruction or perforation.
- Computed tomography (CT scan): A CT scanner uses X-rays and a computer to create images of the abdomen. CT scanning can help identify some abdominal conditions, such as appendicitis and cancer.
- Magnetic resonance imaging (MRI scan): Using radio waves in a magnetic field, a scanner creates highly detailed images of the abdomen. In the abdomen, MRI is usually used to check the liver, pancreas, and gallbladder, but a CT scan may also be used.
- Abdominal ultrasound: A probe on the abdomen reflects high-frequency sound waves off the abdominal organs, creating images on a screen. Ultrasound can detect problems in most abdominal organs, such as the gallbladder, liver, and kidneys.
- Endoscopic retrograde cholangiopancreatography (ERCP): Using an endoscope advanced to the intestine, a tube is placed into the duct from the pancreas and a fluid that blocks X-rays is squirted into the tubes that serve the gall bladder, liver, and pancreas. Then an X-ray picture is taken to find problems with those organs.
- pH testing: Using a tube through the nose or a capsule in the esophagus, acid levels in the esophagus can be monitored. This can help diagnose GERD or evaluate a treatment's effectiveness.
- Upper GI series (with small bowel follow-through): After swallowing a barium solution, X-ray films of the esophagus and stomach are taken. This can sometimes diagnose ulcers or other problems. In some cases they continue taking pictures as the barium courses through the small intestine.
- Gastric emptying study: A test of how rapidly food passes through the stomach. The food is labeled with a radioactive substance and its movement viewed on a scanner.
- Biopsy: A small piece of tissue is taken to help diagnose cancer, liver or other problems.
- Abdominal surgery: Surgery is often necessary for serious abdominal conditions like cholecystitis, appendicitis, colon or stomach cancer, or an aneurysm. Surgery may be laparoscopic (several small incisions and using a camera and small tools) or open (one large incision, what most people think of as a typical surgery).
- Histamine (H2) blockers: Histamine increases stomach acid secretion; blocking histamine can reduce acid production and GERD symptoms.
- Proton pump inhibitors: These medicines directly inhibit the acid pumps in the stomach. They must be taken daily to be effective. There is, though, some concern about taking them for more than a few months.
- Endoscopy: During upper or lower endoscopy, tools on the endoscope can sometimes treat problems (like bleeding or cancer) that are discovered.
- Motility agents: Medicines can increase contraction of the stomach and intestines, improving symptoms of gastroparesis or constipation.
- Antibiotics: H. pylori infection can be cured with antibiotics, which are taken with other medicines to help heal the stomach.
- Laxatives: Various over-the-counter and prescription medicines can help relieve constipation.