The abdomen is the anatomical area between the chest and the pelvis. In non-medical speak, it is often called the "tummy" or "stomach".

As far as medicine is concerned, the abdomen has a front and two sides. Posteriorly, the area on the outside is called the back and so the back of the abdomen cannot be seen in a normal person.

Inside the body, there is a roof to the abdomen. This is a muscle called the diaphragm which separates the chest from the abdomen. The heart and lungs sit on the top of the diaphragm, the abdominal contents below. Through this muscle, the oesophagus ("gullet") and the major blood vessels, the aorta and inferior vena cava, pass. The diaphragm is used mainly in breathing.

There is no floor to the abdomen. The abdominal cavity goes straight into the pelvic cavity, with the intestines moving freely between the two.

Within the abdomen, the gastrointestinal tract and associated organs are held. The gastrointestinal tract start in the abdomen with the end of the oesophagus, stomach which then goes into the duodenum. The small intestine comes next, namely the jejunum first and then the ileum. In the right lower abdomen, at the end of the small intestine inserts into the large intestine (colon) at a point called the caecum. This then is the start of the large intestine (colon). The colon runs at the back of the abdomen at first called the ascending colon, then comes forward in the upper abdomen to go to the other side at the transverse colon, before descending once again at the back of the abdomen on the left side called the descending colon. At this point it once again comes forward and is called the sigmoid: which joins the rectum at the junction between pelvis and abdomen.

Apart from the gastrointestinal tract, the abdominal cavity has the liver on the upper right side with the associated gallbladder underneath it and the pancreas just below it behind the gastrointestinal tract. On the left-hand side, under the ribs in a mirror image of the liver, is the spleen. The spleen is a lot smaller than the liver.

In the male, the abdominal cavity is a closed cavity with no openings into it.

In the female, there is the potential route into the abdomen through the vagina, cervix, uterus and then out through the fallopian tubes. It is this reason that women who get gynaecological infections are much more likely to get infections in the pelvis or abdomen which spread way beyond the gynaecological organs and can become quite serious.

On a social side, the abdomen is quite an important area of the body. Young people quite often like to show their abdomen if slim - women are often exposing it between tops and bottoms and men like you to show off a "six pack".

Both sexes put on weight on the abdomen if they become overweight - in a male this often been called a "beer belly".

As the abdomen contains a lot of organs that may need surgery, and the abdomen itself is often part of how we view people, any procedures to the abdomen, the plan will be to try to minimise scars.

Keyhole surgery (laparoscopic surgery) is now often used for abdominal operations as the scars can be hidden away successfully. Also aesthetic medicine often involves the abdomen with either laser liposuction or liposuction to reduce the amount of fat, or procedures such as Thermage to reduce wrinkly abdominal skin after pregnancy.