Muscle
Puborectalis
A sling that draws the anorectal junction forward
High-yield
The anorectal angle is dynamic, not a fixed right angle. Puborectalis contributes to continence alongside the sphincters, rectal sensation and other pelvic supports.
Overview
Puborectalis arises from the pubic region on both sides and joins behind the anorectal junction. Its resting activity contributes to the bend between rectum and anal canal. Relaxation during evacuation allows this angle to open in coordination with sphincter relaxation and rectal propulsion.
Reference facts
- Origin
- From the posterior pubic bodies on either side of the symphysis.
- Insertion
- Joins the contralateral fibers behind the anorectal junction, forming a sling with close relationships to the upper anal sphincter complex.
- Innervation
- Sacral motor input through levator ani and variably pudendal-associated branches; studies differ in the relative contributions.
- Action
- Draws the anorectal junction anteriorly during continence and relaxes as part of coordinated defecation.
- Blood supply
- Branches of the regional internal pudendal and rectal arterial networks.
Clinical correlation
Impaired relaxation or paradoxical contraction can contribute to dyssynergic defecation. Diagnosis depends on the clinical picture and functional testing rather than an acute angle on one image alone.
Frequently asked questions
What does the puborectalis do?
The puborectalis draws the anorectal junction anteriorly during continence and relaxes as part of coordinated defecation.
What nerve innervates the puborectalis?
Sacral motor input through levator ani and variably pudendal-associated branches; studies differ in the relative contributions.
Where does the puborectalis attach?
Origin: From the posterior pubic bodies on either side of the symphysis. Insertion: Joins the contralateral fibers behind the anorectal junction, forming a sling with close relationships to the upper anal sphincter complex.
What is the blood supply of the puborectalis?
Branches of the regional internal pudendal and rectal arterial networks.