Gotta Go: Anatomy and Physiology of the Poop Chute

In Low-Tone Pelvic Floor Dysfunction by Kim Buonomo2 Comments

By: Kim Buonomo

Everyone’s had that moment…You don’t have to go to the bathroom AT ALL and then suddenly you’re running to the toilet like there’s no tomorrow. How do things change so quickly? I’m going to teach you about the Rectoanal Inhibitory Reflex (RAIR) and what that means for fecal urgency and incontinence.

In order to have a bowel movement, the pressure of the stool in your rectum should be greater than the pressure in your pelvic floor. This is why your pelvic floor has the ability to contract and relax, so that you can contract and maintain continence when you want to, and relax to allow passage of stool when you want to. At the Pelvic Health and Rehabilitation Center, we often see patients who have trouble relaxing their pelvic floor muscles. This results in things like straining, incomplete emptying, and holding your breath when you have a bowel movement, which all reinforce those bad habits. Pushing against a contracted muscle is like pushing against a closed door. Nothing will get through!

Let’s focus on the pelvic floor for a moment. The whole pelvic floor works together with your abdomen and diaphragm, so a thorough examination of all of these areas by an experienced pelvic floor PT is crucial. There are three pelvic floor muscles that I think about a lot in a patient with fecal urgency. The internal anal sphincter is primarily made of smooth muscle. This is the same kind of muscle that makes up your heart and internal organs and acts without you having to think about it. When the internal anal sphincter senses pressure from stool in the rectum, it stimulates an involuntary reflex that relaxes the sphincter to allow a small amount of stool to move into the lower part of the rectum where it encounters puborectalis.

The way that puborectalis is positioned allows it to act like a sling. When you stand, the sling “chokes” the rectum and maintains continence. When you squat, it eases up on that sling and allows for a bowel movement. If that sling never relaxes to allow a BM, then you won’t be able to poop! This is why we always talk about squatting as the preferred pooping position and why the squatty potty became so popular. Nicole talked about squatting and fecal incontinence in this blog post. There are special mucosal receptors in the lower rectum that give you information about the consistency of whatever you are passing. Your body then can choose the appropriate course of action. So if it’s air or gas, go ahead and cut the cheese! If it’s solid, you contract puborectalis to maintain continence and find your way to a bathroom so you can go in peace. If it’s liquid, you strongly engage puborectalis and the external anal sphincter, squeeze those cheeks and run to the bathroom!

Makes sense, right? So what can make this system go haywire and how can pelvic floor physical therapy help?

First, let me say that there are countless possibilities, and I will only be able to discuss a few of them here. An examination by a skilled pelvic floor physical therapist is important in determining and addressing the cause of your specific dysfunction.

In order to maintain fecal continence, you need three things.

  1. The ability of the rectum to fill with stool.
  2. Awareness of rectal filling (urge).
  3. Ability to propel the stool and relax the pelvic floor muscles in a coordinated fashion.

Pelvic floor PTs can help with all of these in various ways!

  1. The ability of the rectum to fill with stool.

If the motility of the colon is slow,  the stool can take too long to get to the rectum, so it doesn’t fill and stimulate an urge until the stool is too hard to pass without straining. A pelvic floor PT can teach colon massage and educate about other factors in life that affect colon transit time (stress, sleep schedule, diet) to help speed things up naturally. There are a lot of over the counter (OTC) medications that can affect stool consistency and transit time. Physical therapists take pharmacology as part of their training, and while you should defer to a pharmacist for the final word, a PT can help point you in the right direction of OTCs and make sure you aren’t taking medications that counteract each other.

  1. Awareness of rectal filling (urge).

Depending on your specific circumstances, up training (strengthening) the internal anal sphincter or using a bowel schedule AKA bowel retraining can improve your body’s awareness of filling and stimulate an urge. There are also tools that a PT can use to mimic the feeling of the rectum filling with stool, so you can get used to that feeling and associate it with an urge, making you start moving to the bathroom at the appropriate time.

  1. Ability to propel the stool and relax the pelvic floor muscles in an organized fashion.

This is where we shine. Pelvic floor PTs are great at assessing muscle function and motor control/coordination. We can examine tight abdominal muscles, breathing patterns, pelvic floor tone, motor control (the ability to make the muscles do what you want them to do) and can provide feedback and homework to help this system work more effectively as a unit and get you pooping like a champ! Biofeedback training has been proven to be effective for management of dyssynergic defecation (lack of coordination when you have a bowel movement).

If you have fecal urgency, constipation, or incontinence, I recommend you contact one of our offices to see how we can help you!

 

References:

American Society of Colon and Rectal Surgeons. (2018). Pelvic Floor Dysfunction Expanded Version.  [online] Available at: https://www.fascrs.org/patients/disease-condition/pelvic-floor-dysfunction-expanded-version

Rao SSC, Go JT. Treating Pelvic Floor Disorders of Defecation: Management or Cure? Current gastroenterology reports. 2009;11(4):278-287. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3883497/

GI Society. Canadian Society of Intestinal Research. (2018). Pelvic Floor Dysfunction. [online]. Available at: https://www.badgut.org/information-centre/a-z-digestive-topics/pelvic-floor-dysfunction/

Center for Colon & Rectal Care. (2018) Pelvic Floor and Functional Colon Disorders. [online] Available at: https://www.ccrcfw.com/service/pelvic-floor-and-functional-colon-disorders

Herman and Wallace inc. Pelvic Rehabilitation Institute. Bowel Function, Dysfunction and Pathology. www.hermanwallace.com

Comments

  1. Thank you so much for your article. I have been a PT x 30 yrs. and have taken H&W 1a, 2a and am trying to put it all together. Your article was a wonderful synopsis of this. I appreciate your contribution for our patients out there and fellow colleagues.

  2. Thank you for this article. It’s on a subject no one wants to talk about, yet affects many. Thank you!

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