Anismus
（重定向自Spastic pelvic floor syndrome）
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Anismus (or dyssynergic defecation) refers to the failure of the normal relaxation of pelvic floor muscles during attempted defecation.
Anismus can occur in both children and adults, and in both men and women (although it is more common in women). It can be caused by physical defects or it can occur for other reasons or unknown reasons. Anismus that has a behavioral cause could be viewed as having similarities with parcopresis, or psychogenic fecal retention.