The rectum connects the colon to the anus at the end of the large intestine. It’s the place where a person keeps their stool before excreting it.
The rectum, also known as the intestinum rectum, is a component of the digestive system that sits at the end of the large intestine. It is a connection between the GI tract and the anus. It sits after the sigmoid colon, the last portion of the colon, and is where the body stores excrement before expulsion.
The function and architecture of the rectum, as well as common disorders that may affect it, will be discussed in this article.
What is it?
The rectum is the last section of the large intestine closest to the anus, according to the National Cancer Institute. The large intestine is around 5 feet long in total, with the rectum accounting for about 12–15 centimeters of that length.
The intestines employ the muscular walls of the sigmoid colon to push excrement into the rectum when the digestive process is completed. The rectum is where the body stores excrement until it is time to defecate. When the rectum is full, stretch receptors in the wall sense it and stimulate the need to pass stool through the anus.
When to consult a doctor
If a person is having rectal discomfort or any other symptoms that could signal a problem around the anal area, they should see a doctor. Any rectal condition can have a negative impact on a person’s quality of life, so it’s preferable to address the issue as soon as possible to minimize problems. If a person is over the age of 50, they should talk to their doctor about having frequent rectal cancer screenings.
Rectal anatomy
The large intestine is divided into four sections:
- Cecum: Also known as the ileocecal junction, this section joins the small and large intestines. The cecum helps absorb water and any remaining salts during the digestion process.
- Colon: The colon is the longest portion of the large intestine. It also absorbs water and electrolytes.
- Rectum: The rectum stores feces until a person is ready to have a bowel movement.
- Anal canal: The anus is the final portion of the large intestine. It helps a person have bowel movements.
Between the sigmoid part of the colon and the anal canal is where the rectum is located. The sacral and anorectal flexures are two primary flexures, or bends, in the rectum. There are also three lateral flexures, referred to as the Houston valves. These bends help sustain the weight of excrement while also preventing a strong and sudden urge to defecate.
The rectal ampulla, which connects the rectum to the anal canal, is located at the end of the rectum. The ampulla’s function is to act as a brief holding area for feces before it is released through the anal canal. When the ampulla fills up, the intrarectal pressure forces the walls of the anal canal to swell and expand, allowing excrement to enter.
Common rectal conditions
The following are some of the conditions that might affect the rectum:
Hemorrhoids
Hemorrhoids are enlarged veins in the rectum and anus that protrude. They don’t always create symptoms, but when they do, patients may have the following symptoms:
- discomfort, irritation, or itching in the anal area
- pain in the anal area
- sensitive lumps
- bleeding during defecation
- protrusion of skin during bowel movements
Infections
A variety of infections can affect the rectum, causing itching, discomfort, and proctitis, among other unpleasant symptoms.
An individual may contract a sexually transmitted infection (STI) after indulging in anal sex, for example. This can include things like:
Antibiotics can sometimes cause a bacterial infection of the rectum. This is due to the fact that antibiotics can kill the good bacteria that keep pathogens like Clostridioides difficile , away. The germs can then grow out of control and invade the rectum.
Infections of the rectum and rectal tissues can also be caused by the fungus. The following are some examples of fungal diseases:
- histoplasmosis
- mucormycosis
- cryptococcosis
- candidiasis
Parasites can enter the body and cause disease, especially when cleanliness is poor. Protozoa, which are single-celled organisms, and helminths, which are worms, are the two most common parasitic infections in the bowel. Parasites can cause a variety of issues affecting various parts of the gut, including the rectum.
Anal abscess
A collection of pus in the tissue surrounding the anus or rectum is known as an anal abscess. One usually happens after an illness or an obstruction. A perirectal abscess is a type of rectal abscess that affects roughly 68,000–96,000 persons in the United States each year, according to data. A doctor would usually cut and drain the pus-filled cavity as part of the treatment.
Prolapse
Rectal prolapse occurs when a portion or all of the rectal wall passes through the anal sphincter, the seal that keeps the rectal contents contained. The weakening of the muscles that support the rectum is the most common cause of this illness.
Rectal prolapse can be classified into three categories:
- External: The entire rectum wall protrudes out of the anus, also known as full-thickness or complete prolapse.
- Mucosal: Only the mucosa, or anus lining, protrudes through the anus.
- Internal: Also known as an incomplete prolapse, the rectum folds in on itself but does not protrude out through the anus.
Incontinence
The rectum is vital for managing defecation and maintaining continence because it retains excrement. If a person’s rectum suffers from muscle injury, nerve damage, prolapse, or scarring, it’s possible that the rectum is unable to function properly, causing stool to seep from the anus.
Rectal cancer
Rectal cancer is a disease in which cancer cells grow in the rectum’s tissues. Rectal cancer can cause the following symptoms, which are not always present:
- bright red blood in stool
- leaks of diarrhea
- constipation
- pain
- changes in bowel habits
Colon and rectal cancers are the second leading cause of cancer death in the United States. Surgery, radiation therapy, chemotherapy, targeted therapy, and immunotherapy are all possible treatment options.
Rectal health advice
People can try to practice proper anal hygiene to assist preserve rectal health and prevent rectal disorders. This can involve things like having regular bowel movements and using safer sex. Furthermore, lifestyle adjustments can aid in improving rectal health and lowering the risk of rectal cancer. These can include the following:
- avoiding alcohol
- reaching or maintaining a moderate body weight
- maintaining a nutritious, balanced diet
- avoiding smoking
- exercising regularly
Conclusion
The rectum connects the colon to the anus and is the last segment of the large intestine. It’s the place in the body where stool is kept until a person is ready to poop.
The rectal area can be affected by a variety of disorders. By producing pain, discomfort, and incontinence, any of these can lower quality of life. If a person is having problems with their bowels, they should see a doctor for a diagnosis.
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