Puboperineales: Muscular boundaries of the male urogenital hiatus in 3D from magnetic resonance imaging

Purpose: The aims of this report are 1) to extend our previous two-dimensional magnetic resonance imaging study to create a three-dimensional image of the pelvic floor, including the puboperinealis, the most anteromedial component of the levator ani; 2) to clarify the historical controversy about this particular component of the levator ani; and 3) to present clinical implications of this muscle with respect to urinary continence and radical prostatectomy. Materials and Methods: We reused the axial magnetic resonance imaging series from 1 of 15 men in a previous series. Analyze AVW(TM) allowed creation of three-dimensional images. Further, a movie clip of all three-dimensional images was developed and placed at the manuscript-dedicated Web site: http://www.mayo.edu/ppmovie/pp.html. Results: Our three-dimensional images show how the puboperinealis portion of the levator ani flanks the urethra as it courses from the pubis to its insertion in the perineal body. Conclusions: The puboperinealis corresponds to muscles previously designated as the levator prostatae, Wilson's muscle, pubourethralis, and levator urethrae, among others. The images suggest that the puboperinealis is the muscle most responsible for the quick stop phenomenon of urination in the male. Our study supports the suggestion that weakening of the puboperinealis by transection, traction injury, or denervation may affect urinary continence after radical prostatectomy.