Why do humans have an appendix?

The appendix is a small, worm-shaped tube, about 3-inches long and one quarter-inch to one-inch thick. It's located on right side of the lower abdominal cavity, coming out of the large intestine. The wall of the appendix is made up of muscle and lymphoid tissue that helps neutralize waste materials generated in the body. However, its function as a waste neutralizer is, well, a waste. The human body can function without an appendix. As a matter of fact, it is considered a remnant of some previous organ that once upon a time helped our ancestors digest things we know longer eat today.

So if the appendix is mostly useless why does it cause so much trouble by getting inflamed and sometimes bursting?

Appendicitis occurs when waste or foreign matter blocks the opening between the large intestine and the appendix. This blockage causes the appendix to produce mucus, which causes swelling. If not removed, the appendix could burst and cause infection -- and possibly death.

Appendectomies are one of the most common emergency surgical procedures. It is estimated that 7% of the U.S. population will have an appendectomy during their lifetime. Appendicitis is most common in people ages 10 to 30. Symptoms include pain around the belly button, nausea, vomiting, constipation, diarrhea, low fever and abdominal swelling.

Resources

Read a fact sheet on appendicitis from the National Institutes of Health.