Abstract: Until now, anatomy of the lower urinary tract still persists for controversial discussion. Especially, the basis of the continence mechanism is still obscure. On the basis of our own extensive histomorphological investigations using above 30,000 serial sections, we defined functional muscular units including sphincter systems and longitudinal urethral muscles. Wefound two independent sphincter systems of the bladder neck: (1) a distinct sphincter encircling the bladder outlet, denoted “musculus sphincter vesicae” and (2) a sphincteric system of the urethra, comprising an inner smooth muscular layer and an outer striated muscular layer, called musculus sphincter urethrae. In men this sphincter system does not completely encircle the urethra, leaving a gap at the dorsal aspect. We found distinct urethral longitudinal muscles of which the ventrolateral musculature originates at the caudal lower edge of the symphysis, runs cranially, crossing the vesical sphincter, and then runs caudally along the urethra to insert into the bulbus penis in men and into the bulbi vestibuli in women. Contraction of this muscle will shorten the urethra and open up the bladder outlet, forming the funnel seen in videourodynamic examinations and therefore was called musculus dilatator urethrae. The dorsal gap left by the horseshoe-like urethral sphincter is filled by another urethral longitudinal muscle in men, which we denoted “musculus ejaculatorius” because of its likely role in the ejaculation process. This muscle emanates from the muscular coat of the ejaculatory ducts and is the morphological basis of the crista urethralis, which is a familiar aspect during cystoscopy of men. Observation of this complex muscular anatomy is supported by a step-by-step development of a computer-animated three-dimensional model of the lower urinary tract. This is an historical video of an important urological procedure that may be of interest to urologists today. The content of the video reflects the views of the authors, and the techniques and technologies used by the authors, at the time the video was produced. The complete author disclosures are no longer available. Runtime of video: 9 min 43 sec
Publication Year: 2010
Publication Date: 2010-02-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 1
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