1. Appendicitis and Appendectomy Slideshow Pictures
2. Medical Illustrations of Appendix Image Collection
3. Take the Appendicitis Quiz

Medical Author:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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In this Article

• Appendicitis facts
• What is the appendix?
• What is appendicitis and what causes appendicitis?
• What are the complications of appendicitis?
• What are the symptoms of appendicitis?
• How is appendicitis diagnosed?
• Why can it be difficult to diagnose appendicitis?
• What other conditions mimic appendicitis?
• How is appendicitis treated?
• How is an appendectomy done?
• What are the complications of appendectomy?
• Are there long-term consequences of removing the appendix?
• What is new about appendicitis?
• Pictures of Appendicitis & Appendectomy - Slideshow
• Medical Illustrations of Appendix Image Collection
• Take the Appendicitis Quiz
• Appendicitis FAQs
• Patient Comments: Appendicitis - Complications
• Patient Comments: Appendicitis - Causes
• Patient Comments: Appendicitis - Symptoms
• Patient Comments: Appendicitis - Treatments
• Find a local Doctor in your town
• Appendicitis Index

The appendix is a closed-ended, narrow tube up to several inches in length that attaches to the cecum (the first part of the colon) like a worm. (The anatomical name for the appendix, vermiform appendix, means worm-like appendage.) The open central core of the appendix drains into the cecum. The inner lining of the appendix produces a small amount of mucus that flows through the open central core of the appendix and into the cecum. The wall of the appendix contains lymphatic tissue that is part of the immune system for making antibodies. Like the rest of the colon, the wall of the appendix also contains a layer of muscle, but the layer of muscle is poorly developed.

Appendicitis means inflammation of the appendix. It is thought that appendicitis begins when the opening from the appendix into the cecum becomes blocked. The blockage may be due to a build-up of thick mucus within the appendix or to stool that enters the appendix from the cecum. The mucus or stool hardens, becomes rock-like, and blocks the opening. This rock is called a fecalith (literally, a rock of stool). At other times, it might be that the lymphatic tissue in the appendix swells and blocks the opening. After the blockage occurs, bacteria which normally are found within the appendix begin to invade (infect) the wall of the appendix. The body responds to the invasion by mounting an attack on the bacteria, an attack called inflammation. An alternative theory for the cause of appendicitis is an initial rupture of the appendix followed by spread of bacteria outside of the appendix. The cause of such a rupture is unclear, but it may relate to changes that occur in the lymphatic tissue that lines the wall of the appendix, for example, inflammation.

If the inflammation and infection spread through the wall of the appendix, the appendix can rupture. After rupture, infection can spread throughout the abdomen; however, it usually is confined to a small area surrounding the appendix (forming a peri-appendiceal abscess).

Sometimes, the body is successful in containing ("healing") the appendicitis without surgical treatment if the infection and accompanying inflammation do not spread throughout the abdomen. The inflammation, pain and symptoms may disappear. This is particularly true in elderly patients and when antibiotics are used. Patients then may come to the doctor long after the episode of appendicitis with a lump or a mass in the right lower abdomen that is due to the scarring that occurs during healing. This lump might raise the suspicion of cancer.