Anatomical fundamentals of urinary continence

The morphological fundamentals of urinary continence are still subject to c ontroversy. This was the reason for a renewed examination of the sphincter musculature of the lower urinary tract. This study included 50 male and 15 female autopsy specimens. The organs of the lower urinary tract including t he neighboring organs had been removed in their entirety and histologically reprocessed en bloc as a complete series of sections. We were able to demonstrate that the internal sphincter or m. sphincter ves icae is represented as a circular, distinct structure which elliptically em braces the internal urethral orifice. Lamellas of the detrusor are not invo lved in the formation of the internal sphincter. In females and males,the e xternal sphincter consists of a striated and a smooth muscular part (m. sph incter urethrae transversostriatus et glaber). In transverse sections, the muscle has a horseshoe shape. It is completely separated by connective tiss ue from the musculature of the pelvic floor. A deep transverse perineal mus cle does not exist. The histological findings were used for the construction of a digital three -dimensional model of the anatomy of the lower urinary tract. Computer anim ations of the model with integrated original histologies were generated and stored as a computer video on a CD-ROM attached to this journal.