[Anatomy of the urethral sphincteric vesico-prostatic complex]

Abstract

As 27 different names have been proposed for the components of the urethral sphincter, it is difficult to build a clear anatomical model of it. Starting from a review of the literature and from some personal observations of surgical anatomy, our aim is to draw a vision as much organic as possible of the anatomy of the urethral sphincter. The components of the urethral sphincter are: the bladder neck (preprostatic sphincter), the smooth muscle urethral sphincter, the rhabdosphincter and levator ani muscle. Recently the rhabdosphincter has been proposed as a vertical structure that extends from the pelvic cavity (bladder base) to the perineal cavity. It can be round-shaped or omega-shaped. The anterior insertions are along the anterolateral aspect of the prostate (superiorly) and on the perineal fascia (inferiorly). The posterior insertions are on the Denonvilliers fascia and posterior aspect of the prostatic apex (superiorly) and on the central perineal tendon (inferiorly). The rhabdosphincter has strong means of fixations: anteriorly it is fixed to the pubis by the pubo-urethral ligaments, posteriorly it is supported by the medial fibrous raphe of the perineum. The anteromedial fibres of levator ani muscle are involved in the continence mechanism by their strong relation with the rhabdosphincter and the prostate.