rectum

Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.

More about the experts All content is checked by medical journalists.

The rectum, also called the rectum or rectum, is the last section of the large intestine. It opens out via the anus (anus). Despite its name, the rectum (Latin rectus = straight) is by no means straight, but runs in two curves. It serves as a store for feces and, together with the internal sphincter, ensures continence. Read everything you need to know about the rectum!

What is the rectum?

The rectum (rectum or rectum) is the last section of the colon. It is about 12 to 15 centimeters long and begins approximately at the level of the 3rd sacral vertebra in the small pelvis - this is the narrowest part of the large intestine.

The rectum has two curves: one points back towards the spine, the other towards the front. In addition, there are constrictions on both sides of the rectum with bulges in between.

Inside the rectum has three crescent-shaped transverse folds. The middle fold is the largest and is called the Kohlrausch fold. It is about six to eight centimeters above the anus and, in men, at the level of the prostate. A medical examination of the rectum with the finger (digital examination) is possible up to this transverse fold.

The upper part of the rectum is called the ampulla (ampulla recti). This particularly expandable section of the intestine serves as a store for the feces. It leads outward through the three to four centimeters long anal canal (the lower section of the rectum) and the anus.

The longitudinal muscle layer, which is bundled into taenia in the wall of the other sections of the large intestine (cecum, colon), forms an even, closed muscle jacket in the rectum - similar to the small intestine.

What is the function of the rectum?

The rectum function is to store the stool in the ampoule. The intestinal contents can be stored here for 16 to 20 hours. The lower part of the ampoule remains closed until the stool is evacuated (defecation), which can be controlled deliberately and over time. If the ampoule is filled with feces, an urge to defecate occurs. This can be suppressed at will.

The sphincter muscles in the anal canal (sphincter apparatus) ensure continence. There are two important ring muscles:

• the internal sphincter: consists of smooth muscles and works involuntarily
• the external sphincter: consists of striated muscles and works voluntarily

Other muscles are also important for continence, for example the muscles of the pelvic floor.

Where is the rectum located?

The rectum lies in the small pelvis. In the upper section it is firmly fused with the rear wall of the trunk. To the rear, the rectum borders on the sacrum, the coccyx and the posterior sections of the muscle that close the pelvic outlet. The male rectum borders the prostate, the vesicle glands, the vas deferens and the area of ​​the urinary bladder in between. In women, the uterus rests on the rectum and bundles of muscles radiate from the back of the cervix to the rectum. The vagina lies at the back and below the rectum.

What problems can the rectum cause?

Cancer of the rectum (rectum carcinoma) often only becomes noticeable in the advanced stages through symptoms. For example, it can lead to abdominal pain, blood in the stool and a change between constipation and diarrhea.

Inflammation of the rectum is called proctitis. There is also chronic bowel inflammation that can extend to the rectum - Crohn's disease.

Constipation (constipation) can be caused by a disturbed evacuation reflex.

A weakness of the pelvic floor (insufficiency) can lead to a prolapse of the rectum, whereby the rectum protrudes out of the anal opening after defecation.

Tags:  pregnancy healthy workplace first aid