A Complete Guide to the Rectum

The rectum is the second-to-last part of your digestive tract, sitting right before the anus. The rectum is responsible for storing stool (poop) and then moving it toward your anus, where it leaves the body. Your rectum plays an important role in managing the defecation process and ensuring you maintain continence, which is the ability for you to control your bowel movements.

Consequently, if there is something wrong with your rectum, it may lose its ability to function normally. In some cases, this can lead to leaking feces, known as fecal incontinence. Understanding how the organ works and learning tips on how to best care for it may help you keep your rectum functioning properly.

Anatomy of the Rectum

The rectum is a muscular tube that is about 5 inches long. It is part of the large intestine, positioned between the colon and the anal canal. Located in the pelvic area above the pelvic floor, the rectum follows the curve of the sacrum (a triangular bone at the end of your spine) and is attached to the sacrum by connective tissue.

The rectal wall is made of five layers. Starting from the interior, these five layers are the mucosa, deep mucosa, submucosa, muscularis propria, and serosa. The rectum also has three bends in its sides made of submucosal folds. These bends are called valves of Houston. Typically, you will find two folds on the left and one on the right. The three valves of Houston help you control the waste in your rectum.

The rectum ends at the anal canal, which is about 2 inches below the tip of the tailbone. This final portion of the rectum is called the ampulla and rests on the pelvic diaphragm. The ampulla is where your stool accumulates and is temporarily stored until you are ready to make a bowel movement.

Some babies might have birth defects that affect the way their rectum is shaped. These defects are known as anorectal malformations. Usually it's the anus that doesn't develop correctly. But in rare cases, the defect could cause the rectum to be blocked or narrowed. The malformation of the rectum would need to be corrected with surgery.

What Does the Rectum Do?

The main role of the rectum is to temporarily provide storage for feces. Once your rectum is storing a certain amount of feces, your defecation reflex will be triggered.

Here's how the defecation reflex is triggered: As your rectum fills with feces, stretch receptors in the wall of your anus are activated. These receptors send signals along nerves to your brain which are processed and then sent back to the lining of the anus. The return signal causes your inner sphincter to open, letting you know it's time to make a bowel movement. The stool is directed from the rectum, to the anus, and out of the body. After you go to the bathroom, this inner sphincter will close again, and you should feel like you don't have to go for a while.

The rectum also helps you stay in control of your bowel movements.

Associated Conditions

Having issues with the rectum is common. While talking about symptoms associated with rectal problems may be uncomfortable, doing so can help you get the care you need.

Hemorrhoids

When there is too much pressure on the veins around the anus, hemorrhoids can occur in the lower part of your rectum. Pressure could come from a variety of situations, including straining during a bowel movement or sitting on the toilet for too long.

There are two types of hemorrhoids: external and internal hemorrhoids. It are the internal hemorrhoids that affect your rectum, occurring in the lining of your anus and lower rectum. (External hemorrhoids occur outside the anus.) Internal hemorrhoids can cause you to have bloody stool.

Polyps

Polyps are growths that can form on the lining of your rectum. They can also grow on your colon's lining. Polyps don't usually cause any symptoms, but when they do, you might experience bloody stools or a change in bowel habits. Most times, polyps are not cancerous (benign). But because they might eventually develop into cancer, it's best to remove polyps. Polyps can be removed during a colonoscopy, a procedure where a flexible tube with a camera is put up your rectum.

Fecal Incontinence

Sometimes called bowel incontinence, this condition makes it so that you cannot control your bowel movements. For example, you might not be able to make it to the toilet in time after you feel the urge to make a bowel movement.

Although this condition can affect people of any age, is occurs most often among older adults and women. There are a number of reasons why someone might experience fecal incontinence, including pelvic floor disorders or damaged nerves in the rectum or anus. Constipation and diarrhea can also cause fecal incontinence.

Inflammatory Bowel Disease

There are two types of inflammatory bowel disease (IBD): Crohn's disease and ulcerative colitis. Both conditions are characterized by inflammation along the digestive tract. In Crohn's disease, the inflammation can be anywhere along the digestive tract—from the mouth to the anus, which would include the rectum. In ulcerative colitis, the inflammation can affect the colon or rectum.

IBD can cause symptoms like abdominal pain, bloody stools, and fatigue. If inflammation continues, the digestive tract can become destroyed.

Colorectal Cancer

This type of cancer develops in the tissues of your colon or rectum. When cancer begins in the rectum, it can be referred to as colorectal cancer, though it might also be called rectal cancer. Genetic variations sometimes lead to rectal cancer, but lifestyle and environment can play a role in its development too. Smoking and having ulcerative colitis or Crohn's disease also can increase your risk of rectal cancer.

Abscesses

Abscesses are pus-filled pockets that can form anywhere on or in the body, including in the spaces around the rectum. The majority of rectal abscesses are caused by an obstruction that becomes infected in the glandular crypts of the rectum. If you have an abscess in your rectum, you might have pus coming from your rectum or experience pain when making a bowel movement. Left untreated, infection can spread. Treatment for an abscess includes an incision and drainage as well as antibiotics for infection.

Fecal Impaction

When a mass of dry, hard stool stays stuck in the rectum, this is called fecal impaction. It often occurs after chronic constipation or the overuse of laxatives. You are more likely to experience fecal impaction if you are sedentary or have a disease that impacts your nerves around the intestines.

Prolapsed Rectum

When your rectum sags from its normal position and partially comes out the anus, your rectum is considered prolapsed. Having a prolapsed rectum can lead to fecal incontinence. If you have a prolapsed rectum, you may notice a reddish-colored lump that sticks out of the opening of your anus. Not only is this mass more prominent after a bowel movement, but it also may bleed and can be particularly uncomfortable or painful.

Diagnostic Testing

If your healthcare provider suspects an issue with your rectum, they may order tests to gain insight into how your rectum looks and how it's functioning. Here are some common tests that can be used:

• Digital rectal exam: A healthcare provider uses a lubricated, gloved finger to feel the lower part of the rectum for lumps, masses, or anything else that seems abnormal.
• Anoscopy: A healthcare provider uses a small tube called an anoscope to look at your anus and rectum. This test can help healthcare providers look for issues such as hemorrhoids, fissures, and abnormal growths.
• Colonoscopy: Using a colonoscope (a long, flexible tube with a camera on the end), healthcare providers are able to look inside the colon and rectum for polyps, inflammation, or other signs of damage or disease. Sometimes small tissue samples are taken and evaluated in a lab.
• Flexible sigmoidoscopy: For this procedure, a tubed camera is inserted into your rectum and lower colon. The lighted camera can show whether there are any abnormal areas in your rectum. The procedure is similar to a colonoscopy, but the tube does not go up as high.
• Defecating proctography: During this study, your rectum is filled with a paste containing a contrast that resembles the consistency of your stool. Then, you are asked to sit on a toilet inside an X-ray machine. As you squeeze, tense your abdomen, and evacuate the material, X-rays are taken. Afterward, the images are evaluated to look for a number of things, including rectal prolapse.
• Manometry: This test measures pressures in the rectum and is used to determine the strength or weakness of your anal muscles. It also evaluates the reflex capabilities of your rectum. Healthcare providers may use this test to look at why you may be having issues with incontinence, constipation, and pain.
• Balloon capacity and compliance: This test evaluates the function of the rectum and its ability to expand and contract. Using a thin, plastic catheter, a healthcare provider will insert an empty, soft, latex balloon through the anus into the rectum and then slowly fill it with warm water.
  

Tips for Keeping Your Rectum Healthy

Keeping your rectum healthy means keeping your bowel movements regular. You should do your best to avoid constipation or diarrhea.

One way to keep yourself regular is to eat the amount of daily fiber recommended for you. Depending on your age and sex, you might need anywhere from 20-35 grams of fiber a day. Examples of high-fiber foods include fruits, vegetables, whole grains, nuts, and beans.

Especially if you eat a lot of fiber or take a fiber supplement, you should be drinking plenty of water. Together, the fiber and water can help keep you regular.

Keeping active can also play a role in you having normal bowel movements.

All these lifestyle habits are also ways to prevent cancer in your rectum. Another way you can prevent rectal cancer is by getting regular colorectal cancer screenings.

It's recommended that everyone at average risk starts getting screened for colorectal cancer when they are 45. This screening can be done via colonoscopy. You might need a colonoscopy sooner if you are at higher risk for the cancer. You could be at higher risk if you have a personal or family history of colorectal polyps or colorectal cancer or if you have IBD.

You can also try to prevent colorectal cancer by limiting your alcohol intake and quitting smoking if you smoke.

A Quick Review

The rectum is the second-to-last part of your digestive tract, sitting right after the colon and right before the anus. Your rectum is responsible for storing stool until you feel the urge to make a bowel movement and then transporting that stool to your anal canal. There are a number of conditions that can affect your rectum, including colorectal cancer, hemorrhoids, abscesses, and fecal incontinence.

If your healthcare provider suspects you have a rectal issue, there are several tests they can perform for evaluation. Diagnosing and treating any problems can help keep your rectum working as best as possible. Even if you don't have any conditions affecting your rectum, there are still things you can do to keep your rectum healthy. This can include getting colonoscopies at the recommended times, eating a high-fiber diet, and staying active.