Dyssynergic Defecation Causes and Symptoms

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Dyssynergic defecation is a health condition with difficulty passing stool due to problems with the muscles and nerves of the pelvic floor. It can result in chronic constipation. Dyssynergic defecation is considered to be the result of pelvic floor dysfunction, in that the muscles and nerves within the pelvic floor are not functioning as they should. A common name for it in the past was anismus.

About half of the patients seeking treatment for chronic constipation are found to have dyssynergic defecation when diagnosed by specialists. This condition often has a negative impact on the quality of life, affecting the work and social lives of those diagnosed with the disorder.

Dyssynergic Defacation
Illustration by Nusha Ashjaee, Verywell 


The symptoms of dyssynergic defecation parallel those of chronic constipation.

  • Abdominal bloating
  • Excessive straining
  • Feeling of incomplete evacuation
  • Hard stools
  • Less than three bowel movements per week
  • Digital evacuation (using fingers to assist in a bowel movement)


It helps to better understand the problem of dyssynergic defecation if you can visualize what the lower end of your digestive system looks like. Your rectum lies at the bottom of your long intestine. The rectum stores stool and is the passageway for stool to make its way out through your anal canal, where it ultimately exits through your anus.

Muscles within the pelvic floor, including those of your abdomen, rectum, and anus, must all work together for the coordinated passage of stool. The muscles of your anal canal include the levator ani muscles and the puborectalis muscle. The anal canal also has two sphincters, an internal sphincter, and an external sphincter, which helps you maintain continence.

In dyssynergic defecation, it appears that the coordination between the muscles that make up the pelvic floor is impaired. In attempting to understand what is going wrong in dyssynergic ​defecation, specific attention is given to the puborectalis muscle and the internal and external sphincters of the anus. Improper contraction and/or relaxation of these muscles during bowel movements appear to be major contributors to the problem.

To complicate things further, there is some evidence that some individuals who suffer from dyssynergic defecation have an impairment in their perception of stool within the rectum. This may lead to missing cues about the need to initiate a bowel movement, thus exacerbating the constipation problem.

To sum it up, dyssynergic defecation is the result of the following problems:

  • Impaired awareness of the need to defecate
  • Impaired pushing
  • Rectal contraction is inadequate
  • Contraction of the puborectalis muscle when it should be relaxing
  • Contraction of the internal and external sphincters when they should be relaxing
  • A combination of any of the above factors

In many cases, no specific factor can be identified as causing dyssynergic defecation. For some people, the problem begins in childhood. Other causes have been noted:

  • Childbirth
  • Pregnancy
  • Rectal injury
  • Repeated passage of hard stool
  • Sexual abuse


Speak to your healthcare provider if you suspect that your constipation problem may be the result of dyssynergic defecation. Your healthcare provider may recommend some diagnostic procedures and then will work with you to devise a treatment plan.

Alternate Names

The condition of dyssynergic defecation has been called by a wide variety of names over the years, including:

  • Anal sphincter dyssynergia
  • Anismus
  • Obstructive defecation
  • Paradoxical puborectal contraction
  • Pelvic floor dyssynergia
  • Pelvic outlet obstruction
  • Spastic pelvic floor syndrome
3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Dyssynergic defecation: about a common cause of chronic constipation. IFFGD.

  2. Rao, S. Pelvic floor dysfunction. Revista de Gastroenterologia de Mexico 2010 75:72-82.

  3. Shim, L., et.al. Predictors of outcome of anorectal biofeedback therapy in patients with constipation. Alimentary Pharmacology and Therapeutics 2011 33: 1245-1251. doi:10.1111/j.1365-2036.2011.04653.x

By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.