Function of the Douglas space

In healthy people, the Douglas cavity is a free cavity within the abdominal cavity and therefore has no function of its own. In women, it separates the rectum from the uterus. Its walls are lined with peritoneum.

This consists of a thin layer of cells, a so-called epithelium. The peritoneum continuously secretes a thin film of fluid which, like a lubricant, makes it easier for the organs to slide past each other during various movements. In addition, a network of blood and lymph vessels and nerves runs through it. They are important for the defence against disease and sensitivity to pain. In so-called peritoneal dialysis, a procedure in which the peritoneum acts as a filter for the kidneys, the Douglas space is used as a fluid reservoir.

How can you feel the Douglas space?

Normally, the examiner palpates the Douglas space via the rectum or the rearmost section of the intestine. The patient lies on his side with his legs bent. The use of gloves and lubricant makes the examination as painless as possible.

The Douglas space is located in front of the rectum. Therefore, the examiner can now examine it from the inside by palpating the front wall of the rectum. Alternatively, in women the Douglas cavity can also be palpated via the back wall of the vagina as part of a gynecological examination.

Pain in the Douglas space

Pain in the Douglas cavity can have various causes. Due to the location of the Douglas cavity, they are usually perceived as abdominal pain. Initially, pain affecting the Douglas cavity is mainly perceived by women during sexual intercourse.

In this case, the back wall of the vagina is irritated, which may be directly adjacent to the Douglas cavity in the upper third. Frequent causes are pain due to diseases of the surrounding organs. These are usually the rectum, uterus, ovaries and vagina.

Pain in these organs can radiate into the Douglas cavity. The wall of the Douglas cavity consists of peritoneum, which can become inflamed. This inflammation is called peritonitis.

An inflammation within the peritoneal cavity, such as appendicitis, can lead to the formation of a so-called Douglas abscess.In this process, purulent substance from the actual inflammation reaches the Douglas cavity and encapsulates itself there. The neighboring organs, especially the uterus and rectum, can collapse into the Douglas cavity. This so-called hernia is also called a Douglas cell in the Douglas cavity.

If it pushes forward, it can usually be felt on the back wall of the vagina. Another possible cause of pain in the Douglas cavity is so-called endometriosis. This disease is widespread and occurs when the lining of the uterus grows outside the uterine cavity.

This is possible throughout the entire body. However, the Douglas cavity is particularly frequently affected due to its close proximity. Endometriosis is basically benign, but it is fully functional uterine tissue.

Therefore, it participates in hormone action and the menstrual cycle. Complaints often occur in connection with menstruation. Symptoms are increased menstrual bleeding and pain, as well as menstrual disorders.

Infertility can also occur. The symptoms subside when the menopause is reached. More dangerous is the so-called ectopic pregnancy. In this case, the fertilized egg does not migrate into the uterus, but leaves the fallopian tubes and falls into the abdominal cavity, where it can grow firmly and trigger a pregnancy within the abdominal cavity. Again, the Douglas cavity, as the deepest point of the abdominal cavity, is particularly at risk.