Appendix: Definition, Side, Role, Pain, What Is It?

The appendix is a short extension of the caecum in the abdomen. Its role is still quite unknown. It is the organ which is affected by appendicitis.

Appendix: Definition, Side, Role, Pain, What Is It?
Appendix: Definition, Side, Role, Pain, What Is It?

What is an appendix?

The appendix, also known as the vermiform appendix or ileocecal appendix, is a short extension in the shape of a tube of the caecum, at the start of the large intestine. It varies in size, from 4 to 12 cm long and 4 to 8 mm in diameter. The appendix is found on the right side of the abdomen. According to some, the appendix can be found in different places in the abdominal cavity. It can also be found in the right iliac fossa, in the pelvis or the right side. In very rare cases, it has been said that a second appendix has been found.

Role of the appendix

The function of the appendix is unknown. It is considered to be a relic of evolution, playing no role within the body. However, researchers have put forward the theory that it could serve as a storage tank for healthy bacteria in the body.


Appendicitis is the acute inflammation of the appendix. It is characterised by a sharp, sudden pain just below the naval on the right.

It is the most common abdominal medical emergency. In fact, surgery is vital in order to avoid rupturing the appendix which can provoke the perforation of the peritoneum membrane. It involves immediately removing the appendix with a small incision. We call this an appendectomy.