title: Role of male pelvic floor muscles and anterior fibromuscular stroma in males on α(1)-blocker treatment: a magnetic resonance imaging study.
abstract: Dynamic motion of the pelvic floor muscles during voiding was analyzed using real-time magnetic resonance imaging. To evaluate the contraction of the pelvic floor muscles, striated urethral sphincter distance, levator ani muscle thickness and anterior fibromuscular stroma distance were measured. The percent contraction of the striated urethral sphincter from before voiding to just before initiation of voiding was 14% in the normal group and 5% in the voiding dysfunction group. The percent contraction of the anterior fibromuscular stroma from before voiding to just before initiation of voiding was 11% in the normal group and 1% in the voiding dysfunction group; the percent contraction of the muscles was significantly greater in the normal group (P < 0.05). Striated urethral sphincter and anterior fibromuscular stroma contraction at initiation of voiding open the bladder neck and urethra. This plays an important role in the smooth initiation of voiding.
authors.affiliation: Department of Urology, Dokkyo Medical University Koshigaya Hospital, Koshigaya, Saitama, Japan.
authors.forename: Kojiro
authors.initials: K
authors.lastname: Nishio
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Soh
authors.forename: Toshio
authors.initials: T
authors.lastname: Syukuya
authors.forename: Ryo
authors.initials: R
authors.lastname: Sato
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sadaoka
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Iwahata
authors.forename: Keisuke
authors.initials: K
authors.lastname: Suzuki
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ashizawa
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Kobori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okada
mesh_terms: D058668:Adrenergic alpha-1 Receptor Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D017773:Pelvic Floor / Q000502:physiology*; D011467:Prostate / Q000502:physiology; D014521:Urethra / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D014554:Urination / Q000187:drug effects / Q000502:physiology
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists
keywords: anterior fibromuscular stroma; magnetic resonance imaging; pelvic floor muscle; voiding dysfunction; α1-blocker