What is an appendix?

A man holding his stomach in pain.

The human appendix is a vestigial organ, which means that it has lost most, if not all, of its function due to evolution. In humans the appendix is a small remainder of the cecum, which our ancestors used to possess. In animals the cecum is still used to break down tough cellulose that is found in plants. The appendix is located at the join between the large and small intestines and is a small tube with a closed end. If the open end of the tube becomes blocked the appendix will swell and must be removed to prevent it from rupturing

Answered by Claire Butler.