How Your Appendix Works

Location of the appendix.
This diagram shows the location of the appendix at the cecum. Unfortunately, that's also a likely place for infection to occur. See more bodily organ pictures.

Location, location, location. You've likely heard this phrase thrown around in the real estate world, but the truth is it can be used to describe the appendix, too. Except here's the problem: The appendix is in a bad neighborhood. The location of the appendix is at the cecum -- the beginning of the colon where the small and large intestines join -- which places it in a prime spot for infection. The appendix resembles a closed end tube with an opening in the middle that can allow fecal matter to enter, so it's easy to see how an infection in the appendix can quickly develop and become a health emergency. The appendix is only about 3 or 4 inches long, so why all the trouble from such a small organ?

Here's another head-scratcher -- the appendix doesn't appear to have any function in the human body. Scientists theorize that the appendix is a remnant of an ancient digestive tract. They believe that it might have been used by early man to digest tough leaves and bark.


­Because doctors don't really know the purpose of the appendix, they're unable to determine what system it belongs in. It's a simple structure that's made up of two types of tissue. The outside of the appendix is muscle tissue, but given the lack of activity, the muscle is considerably weaker than the muscle tissues that make up other organs. The lining of the appendix is filled with lymphatic tissue, which produces antibodies, leading many to believe that the appen­dix may be part of the immune system. Another odd characteristic of the appendix: It manufactures and secretes a small amount of mucus. No doubt about it, the appendix is confusing.

Of course, it's understood that the human body functions perfectly well without the appendix, but some scientists are still unwilling to declare the appendix useless.

So what is appendicitis, anyway? And what's really happening when an appendix bursts? Find out on the next page.




A microscopic view of an inflamed appendix.
Duncan Smith/Getty Images

Appendicitis -- the most common condition of the appendix -- develops when a blockage forms within the organ. Since the appendix is closed on both ends with an opening along the middle section, any blockage quickly prevents blood flow and causes death of the tissue. A blockage can result from impacted fecal matter or a condition called lymphoid hyperplasia. Lymphoid hyperplasia can be the result of Crohn's disease, irritable bowel syndrome, mononucleosis, measles or gastrointestinal infections. In lymphoid hyperplasia, the appendix produces an overabundance of normal cells. These cells create a blockage in the appendix, causing it to become inflamed, which then compromises blood flow to the area. The loss of blood flow causes the tissue in the appendix to die and eventually leads to the appendix bursting.

How long does it take before an appendix actually bursts? The time it takes between the formation of a blockage and the point where the appendix actually perforates -- or bursts -- is usually around 72 hours. During that time there are several symptoms that indicate something's not right. The first sign is normally a vague pain around the navel. As the inflammation develops, the pain moves toward the right side of the body -- typically in the direction of the hip. Other symptoms that develop over the next 24 hours may include nausea, vomiting, fever and something called "rebound tenderness." In some cases the patient may also experience a swollen abdomen, back pain or even constipation.


If you believe that you have appendicitis, get to the emergency room immediately. Time is critical when dealing with the appendix. You'll most likely be required to have a computed tomography (CT scan) or an ultrasound so they can look at your appendix. This method of diagnosing appendicitis has greatly reduced the number of appendectomies performed on those who are suffering from ailments other than appendicitis. In fact, around 20 percent of appendectomies involve the removal of a healthy appendix.

Appendicitis recovery.
A woman recovering from laparoscopic appendicitis surgery.
Javier Pierini/Getty Images

What happens if the appendix bursts while it's still inside? Clearly, the most effective treatment for appendicitis is to get it out before it bursts. Once the appendix ruptures, it spills inflammatory fluids and bacteria into the abdominal cavity. If the patient has a ruptured appendix prior to surgery, the risk of complications increases 10 times. The appendectomy is usually conducted as a laparoscopic surgery, but in some cases a more invasive, conventional appendix surgery may be necessary.­

The elderly and the very young are most likely to experience complications from appendicitis. Both groups are likely to have nontraditional symptoms, making it even more difficult to diagnose. Young patients often experience diarrhea and vomiting, while elderly patients typically experience less pain. Difficulty in diagnosing appendicitis can lead to peritonitis -- or abscessing -- within the abdomen, which may cause organ failure and death.

Appendectomies are the most common surgical emergency involving the abdomen [source: National Digestive Diseases Information Clearinghouse], and around 20 percent of patients don't even realize that they have appendicitis until their appendix ruptures [source: University of Michigan Health System]. Because of the symptoms, patients may be misdiagnosed with gastroenteritis. The symptoms of each are similar; however, physicians treat gastroenteritis by replacing fluids lost to vomiting and diarrhea -- a treatment which has no effect on the appendix.

While appendicitis is the most common condition of the appendix, it's not the only one. Read the next page to find out what else can go wrong with your appendix.


Other Appendix Conditions

Adenomas grow and compress the appendix causing it to become inflamed (appendicitis). An inflamed appendix is in danger of rupturing.

Appendicitis may be the most common condition of the appendix, but there are a variety of other conditions that can affect this organ:

Carcinoid tumors: Similar to other organs in the body, the appendix can develop tumors. Carcinoid tumors are slow growing tumors that can develop anywhere in the gastrointestinal tract. These tumors are described as either benign or malignant. Benign carcinoid tumors often go undiagnosed, while malignant carcinoid tumors may spread to other parts of the body through the blood stream or lymphatic system. Carcinoid tumors can also cause carcinoid syndrome, which is a debilitating but rare condition.


Appendiceal Carcinoma: Appendiceal carcinoma is a rare form of colorectal cancer that strikes the appendix. The growth of cancer in the appendix can lead to a blockage resulting in appendicitis. Appendiceal carcinoma can also spread to the stomach. The initial diagnosis of appendiceal carcinoma is often delayed because the symptoms are similar to appendicitis.

Adenomas: Adenomas are benign tumors that may develop in and around the appendix. The tumors are the result of an overgrowth of epithelial cells. While they occasionally turn malignant, the main concern with adenomas is that their growth will compress the appendix and lead to appendicitis. Adenomas can develop in other areas of the body, such as on the pituitary or thyroid gland. Because they develop on glandular areas of the body, they secrete hormones.

Diverticular Disease: Diverticular disease is an uncommon condition that has similar symptoms as appendicitis. While appendicitis is most common in those under the age of 30, diverticular disease develops in older patients. The pain from diverticular disease is intermittent, which may result in patients postponing treatment. Because perforation of the appendix can occur from diverticular disease, removal of the appendix is the treatment for this condition.

People are often amazed at the variety of health conditions that can develop in the appendix. Because the organ is often seen as useless, many people wonder if we would be better off without one. Learn what some medical professionals say about the appendix on the next page.


Does the appendix have a function?

Before and after surgery.

The appendix -- an organ barely 4 inches long -- causes much debate among medical professionals. In fact, doctors have trouble deciding if the appendix has any use to the body at all. While everyone agrees that the appendix can be removed without causing any adverse health consequences to the patient, some physicians and researchers believe that the appendix does serve a function as part of the immune system. Others feel that the appendix is a vestigial organ, a remainder from the time when humans regularly dined on tree bark and needed an additional organ to break down the roughage. Along with the disagreement over the true function of the appendix, there is no consensus if humans will always have this organ. Some doctors feel that the evolution of the human body will lead to the demise of the appendix, while others believe that the appendix will remain in the body, continuing to do whatever it does.

Prophylactic appendectomies for astronauts? How about for international travelers?


If the appendix has no purpose, yet is potentially subject to all of these dangerous -- even life threatening -- conditions, then why can't we simply have a doctor remove our appendix as a preventative procedure?

With no clear determination of what the appendix does, there's no agreement on whether prophylactic appendectomies -- appendectomies performed to avoid possible future medical emergencies -- are medically appropriate. For years rumors have circulated that astronauts had their appendixes removed before space travel to avoid a potential medical emergency while in orbit. For similar (yet more earthbound) reasons, many people wonder whether they should have theirs removed before boarding an international flight. There's no truth to the rumor about astronauts, and most physicians do not recommend preventative appendectomies for world travelers either. Seven percent of the general population will have their appendix removed at some point in their lives. Given these low odds, and the fact that most insurance plans will not pay for a prophylactic appendectomy, they are generally not considered for the healthy traveler.

Prophylactic appendectomies are occasionally performed if the patient is undergoing other abdominal surgery. For instance, if the patient has an ovarian cyst removed or a hysterectomy, the doctor may perform an appendectomy at the same time. The reason for this is twofold. If the patient has a history of abdominal pain, such as with endometriosis, that pain can mask the symptoms of appendicitis. Additionally, recovering from abdominal surgery isn't pleasant, and by removing the appendix at the same time as conducting other surgery, you minimize the likelihood of additional surgery.

If you found this article interesting, you may want to read some of the related HowStuffWorks articles listed on the next page. You'll also find a few links that can provide you with more information about the appendix.


Lots More Information

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More Great Links



  • Burney, Richard E. MD. "Acute Appendicitis." University of Michigan Health System. October 2005.
  • Cunha, John P. DO. Durham, Britt A. MD. "Appendicitis Causes, Symptoms, Diagnosis, and Treatment Information." 07/03/2007
  • Katz, Joshua MD. "Appendicitis." National Digestive Diseases Information Clearing House. June 2004.
  • Katz, Michael S. MD. Tucker, Jeffrey R. MD. Glick, Philip MD, MBA. "Appendicitis." September 15, 2006.
  • Lee, Dennis MD. Marks, Jay W. MD. "Appendicitis information (symptoms, diagnosis, treatment)." MedicineNet. 12/07/2007.
  • Van Voorhees, Benjamin W. MD, MPH. "Point Tenderness - Abdomen." MedlinePlus Medical Encyclopedia. 05/17/2007.