Appendix

In human physiology, the appendix is a small sac connected to the large intestine. It was once believed to be a useless and purely vestigal organ; but newer evidence suggests it most likely has a function in the lymphatic system. It is one of a number of areas of the colon where lymphatic tissue is present; but in the appendix it is present in a particularly high proportion, although it degenerates with age and comes to resemble other areas of lymphatic tissue in the colon. It is possible for matter to become logged in the appendix, leading to bacterial infection, or appendicitis. If untreated, the appendix will eventually burst, leading to scepticemia and eventually death. Appendicitis can be treated by removal of the appendix, called an appendicectomy.

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The word appendix can also refer to a small section at the end of a book, often used for supplementary information.