Anatomy

Nerve

A branch from the fourth sacral and twigs from the inferior hemorrhoidal branch of the pudendal supply the muscle.

Actions

The action of this muscle is peculiar.

• It is, like other muscles, always in a state of tonic contraction, and having no antagonistic muscle it keeps the anal canal and orifice closed.
• It can be put into a condition of greater contraction under the influence of the will, so as more firmly to occlude the anal aperture, in expiratory efforts unconnected with defecation.
• Taking its fixed point at the coccyx, it helps to fix the central point of the perineum, so that the Bulbocavernosus may act from this fixed point.