The word originates from Latin to "hang on" and the appendix is a wormlike appendage to the bowel. It hangs off the junction between the small and large intestine in the right lower abdomen. It usually varies from 3 to 6 inches in length and about inch in diameter. However it may be much longer curling up under the liver or dangling down into the pelvis. The significance of this is that it may can cause confusion in diagnosis if it becomes inflamed.

The purpose of the human appendix is not really understood. We do know that some animals have a similar organ, which is used to process vegetable fibre. These animals have larger well-developed appendices. It is thought that maybe our appendix is a remnant of a time when evolution had us digesting fibre, a function our bowel can no longer perform. The human appendix contains lymphoid tissue – the cells that can produce antibodies to fight infection. It isnt really clear why the appendix contains this tissue.

The significance of the appendix really lies in its unfortunate ability to get infected and cause potentially serious even life threatening disease. There are lots of theories about why appendicitis occurs – some believe that bits of partially digested food get caught in the pouch and rot. No matter why it gets inflammed the result is severe pain and if the appendix bursts it can be fatal.

Appendicitis can be one of the hardest or easiest medical conditions to diagnose. I know this sounds contradictory but when a patient presents with classical symptoms even a medical student can make the diagnosis. The trouble is Appendicitis can present in different ways and other conditions can mimic it.

The interesting thing about Appendicitis is how the pain develops. The appendix has nerve fibres that can carry messages back to the brain. This nerve is shared by the area of skin over the umbilicus ( belly button).Strangely the brain doesn’t seem to be able to recognise that the appendix feels pain. So if the organ becomes inflammed a message is sent to the brain – but the brain interprets it as coming from that area of skin over the umbilicus. Consequently initially when someone has appendicitis they "feel" pain in the region of their umbilicus. However as the condition worsens and the appendix becomes more inflammed it causes surrounding tissue to become inflammed as well. As a result the pain becomes localised to the spot where the appendix lies, usually the right lower corner of the abdomen.

The treatment for Appendicitis is appendicectomy (note in Australia we say "append-i-cect-omy" as compared with the American pronunciation of "append-ectomy" – let’s not argue which is right or wrong now ! J ). These days the operation can be doe through a very small incision but never the less it requires a stay in hospital. We seem to see less appendicitis – whether this is due to better diet or better diagnosis I am not sure. But it is not as common an operation as it used to be.

A condition which mimics Appendicitis is Mesenteric Adenitis – Simply put, this is inflammation of the lymph glands that lie beside the bowel. It is often a response to a viral infection and usually settles by itself. People will often be observed in hospital if the diagnosis of appendicitis is not entirely clear, with an surgeon on call ready to go if the patient’s condition changes. Occasionally ovulation pain can mimic appendicitis – however I have seen people who’s "ovulation pain " has ended up being not that but real Appendicitis ! Appendicitis is not a condition for self diagnosis a doctor’s opinion should always be sought!