A NEW THEORY OF MICTURITION AND URINARY CONTINENCE BASED ON HISTOMORPHOLOGICAL STUDIES .3. THE 2 PARTS OF THE MUSCULUS SPHINCTER URETHRAS -PHYSIOLOGICAL IMPORTANCE FOR CONTINENCE IN REST AND STRESS

The urethral component of continence is the object of a lively discuss ion. A large number of the examiners interpret the external striated u rethral muscle as part of the muscular pelvic diaphragm, formed partia lly or completely by the so-called musculus transversus perinei profun dus. About 30,000 histological sections have been examined by light mi croscopy in a systematical manner. In contrast to numerous suggestions in the literature the musculus sphincter urethrae has been found to b e an independent morphological unit in our investigation. It is separa ted from the surroundings by a segment of connective tissue. Furthermo re, with the help of transversal, sagittal and frontal serial sections it was possible to show that the musculus transversus perinei profund us does not exist. In the female as well as in the male in the directi on of the urethra the outer sphincter always borders on a layer of smo oth muscle cells. In order to distinguish both parts the terms musculu s sphincter urethrae transversostriatus and musculus sphincter urethra e glaber are introduced. In the context of a new continence theory thr ee structures capable of occluding the urinary bladder will be discuss ed. It should be emphasized that the musculus sphincter urethrae glabe r makes long-term continence possible.