Puborectalis

General information

The puborectalis muscle is a U-shaped sling muscle which travels from the bodies of the pubic bones, past the urogenital hiatus, and then around the anal canal.

Literal meaning

Straight muscle of the pubic area.

Interesting information

Some of the puborectalis muscles fibres form an additional U-shaped sling over the urethra in males and the urethra and vagina in females. This sling is essential in maintaining urinary continence, particularly during a sudden increase in intra-abdominal pressure for example, during sneezing.

Origin

Posterior surface of bodies of pubic bones.

Insertion

None (forms 'puborectal sling' posterior to rectum).

Function

Maintain faecal continence – during defecation this muscle relaxes.

Nerve supply

It is primarily supplied by nerve to levator ani (S4). To a small degree the pudendal nerve (S2-S4) contributes to its innervation as well.

Blood supply

Inferior gluteal, inferior vesical and pudendal arteries.

Relevant research

Failure of the puborectalis muscle to relax in the absence of a neurologic disorder has been attributed as a major cause of chronic severe constipation, which does not respond to laxatives or fibre supplementation.

Chapter 37 - Neuromuscular Physiology of the Pelvic Floor, Arnold Wald, in Physiology of the Gastrointestinal Tract (Fifth Edition), 2012.

Puborectalis exercises

None specific to this muscle.