Contraction of puborectalis muscle produces anorectal angulation
Internal anal sphincter (IAS) contracts
External anal sphincter (EAS) contracts
Continence is maintained
Note: For continence to be maintained the 𝘼𝙉𝙊𝙍𝙀𝘾𝙏𝘼𝙇 𝘼𝙉𝙂𝙀𝙇 must be less than 90 degrees.
    The correct posture on the toilet is essential to relax the puborectalis muscle, widen the angle and open the canal.

The 𝘼𝙉𝙊𝙍𝙀𝘾𝙏𝘼𝙇 𝘼𝙉𝙂𝙀𝙇 is the angle created by a line drawn through the central axis of the anal canal and a line drawn through either the central axis of the distal rectum or a line drawn parallel to the posterior wall of the distal rectum. It can be measured at rest and during evacuation. Normal values range from 90° to 110° at rest. Normal values increase at evacuation.