Fig. 1.

Structural orientation to levator ani subdivisions and visibility of the puborectal muscle in MR images at two different levels (chosen from multiple contiguous sections as we followed the puborectal^TA muscle from its origin at the pubic bone to its decussation behind the rectum); a lateral view of 3-D model with pubic bones, (B bladder, U uterus, R rectum), b levator subdivisions: without bones (PCM pubococcygeus muscle, ICM iliococcygeus muscle, PRM puborectal muscle^TA, EAS external anal sphincter). c Level of the PRM decussation showing the scan plane for d, revealing the MRI at level of the PRM decussation (outlined), e level where the PRM “arms” project towards the pubic bone; f MRI at the level of the PRM “arms” (outlined in red)