MAGNETIC-RESONANCE-IMAGING OF THE MALE PELVIC FLOOR - THE ANATOMICAL CONFIGURATION AND DYNAMIC MOVEMENT IN HEALTHY-MEN

The male pelvic organs and the rhabdosphincter were visualized using m agnetic resonance imaging (MRI) in five young male volunteers (mean ag e, 25.6 years). The prostate was crescent-shaped in three subjects and doughnut-shaped in two subjects. The external urethral sphincter (EUS ) was located anterior to and lateral to the urethra but was rare on t he rectal side. The membranous urethral length measured 28-35 mm (aver age, 31.0 mm). The pubourethral portion of the levator ani embraced th e urinary bladder, the prostate, and the membranous urethra, and the m ost distal portion of the levator was thickened. During anal contracti on, the EUS became thinner on both coronal and sagittal images and the levator was approximated closer to the urethra. Consequently, the pro state and the bladder base were elevated and the membranous urethra wa s elongated by 0-12 mm (average, 5.6 mm). On sagittal images, the pros tate, the membranous urethra, and the rectum were pulled closer to the pubic bone by anal contraction and the retropubic area became narrowe r. This study clearly demonstrated that MRI was useful in examining th e anatomical configuration of the male pelvic floor and its dynamic mo vement during anal contraction. Neurourol. Urodynam. 17:591-597, 1998. (C) 1998 Wiley-Liss, Inc.