Corpus: Puborectalis muscle

The puborectalis muscle belongs to the pelvic floor muscles and is an important part of the continence organ. It forms a loop around the rectum (puborectalis sling) in the area of the anorectal junction and increases its curvature when contracted (under voluntary control). It is the innermost part of the levator ani muscle.

The muscle has its origin at the os pubis, where it originates with two legs. They run dorsally and surround the rectum.

It is innervated by direct branches from the sacral plexus (L5-S4).

The puborectalis muscle surrounds the rectum in a loop. Contraction (e.g. during the urge to defecate) increases its forward curvature and closes the anal canal. The resulting anorectal angle is important for continence and represents a kink closure.