What Nerve Controls Bowel Movements?

The connection between the bowel and the brain allows us to control when and how we go to the bathroom. This is easy to take for granted when the body functions as it’s supposed to, but when the connection between the bowel and the brain is disrupted due to injury or illness, the resulting complications when it comes to the passing stool can have a profound impact on a person’s quality of life and independence.

Nerve Controls

How the Sacral Nerves Work

The sacral nerves are responsible for overall bowel control. They are located in the pelvic area above the tailbone. The two key sacral nerves for bowel and bladder control are the pudendal nerve and the pelvic splanchnic nerve.

These nerves communicate with the brain through electrical impulses and reflexes that travel along the spinal cord to signal a feeling of fullness in the bowel that allows the anal sphincter to relax and pass stool.

Conversely, the brain also signals the sacral nerves to keep the anal sphincter closed when the rectum is not full to prevent stool leakage and bowel accidents.

About Neurogenic Bowel

What happens with bowel movements when the signal from the sacral nerves to the brain is disrupted due to spinal cord injury or illness?

Damage to the spinal cord disrupts the signals between the sacral nerves and the brain, resulting in the inability of the brain to ‘know’ when the rectum is full and/or when to keep the anal sphincter closed. This condition is known as neurogenic bowel.

How the bowel functions post-injury depends on where the signals are disrupted in the spinal cord.

There are two primary types of neurogenic bowel:

  • Flaccid bowel causes the anal sphincter to be looser than normal and can lead to constipation and/or stool leakage. This typically occurs with a lower spinal cord injury (below T-12).
  • Reflex bowel occurs with damage to the spinal cord above T-12 and doesn’t allow for a voluntary relaxation of the anal sphincter to allow for defecation. The reflex that triggers the urge to have a bowel movement works, but the individual cannot feel when the rectum is full, leading to constipation and bowel accidents.

The Importance of an Effective Bowel Management Program

People with neurogenic bowel need a regular program to manage how and when they pass stool, known as a bowel management program. This allows for optimum quality of life and independence. An effective bowel management program includes lifestyle elements and a routine for passing stool on a predictable schedule.

Incorporating wellness habits to support a bowel management program that includes a balanced, nutritious diet, adequate daily fiber intake, hydration, and a fitness regimen is essential.

Fiber: Eating fiber-rich foods is one of the most important aspects of managing bowel health. There are nutritional bars high in fiber, and some give you as much as 20% of your daily fiber intake. Other high fiber foods include chickpeas, raspberries, broccoli, kidney beans, split peas, pears, avocado, and dark chocolate!

Fitness: Physical movement also helps stimulate the bowel. For people with limited mobility, stretching and range of motion exercises help keep a regular bowel routine.

Hydration: Fluid intake is essential to an effective bowel management program. Adequate non-diuretic fluid intake helps keep stool moving through the gastrointestinal tract and reduces the risk of constipation. Avoid or moderate beverages that can dehydrate the body, like alcohol and caffeine.

Routine: With neurogenic bowel, it’s important to follow a regular schedule to “teach” the bowel when to have a movement. Establish times of day that fit with your lifestyle, and stick to it as much as possible.

Bowel programs typically require 30-60 minutes to complete. It’s preferable to complete the bowel care program on the commode. However, those at risk for skin breakdown should evaluate whether a seated position versus a side-lying position in bed is best. Gravity can assist with bowel movements, so if a seated position on padded or inflatable seats) is possible, this can be helpful.

Laxatives: Laxatives often play an important role in evacuating stool for people with neurogenic bowel, but not all laxatives are the same. It’s important to consult with a physician to understand which type of laxative works best for your particular situation. Studies show that people on a regimented bowel care program that includes oral and/or rectal laxatives to achieve complete rectal emptying had 35% fewer episodes of fecal incontinence and 42% fewer incidents of soiled laundry.

Joshua K. Lopez

I do take care of my health so I do love writing many articles over health and care. Developed several new methods for merchandising tar in West Palm Beach, FL. Crossed the country analyzing human brains in Los Angeles, CA. Managed a small team creating marketing channels for carnival rides in Atlantic City, NJ. Developed several new methods for testing the market for mosquito repellent for fun and profit. Enthusiastic about supervising the production of cabbage with no outside help. Had some great experience consulting about weed whackers in Ocean City, NJ.