A new theory of micturition and urinary continence based on histomorphological studies. 1. The musculus detrusor vesicae: occlusive function or support of micturition?
Micturition and urinary continence theories have been under discussion since the last century. Up to now all these theories have been unsatisfactory. There is an obvious discrepance between the anatomical presentation and the clinical perceptions and physiological phenomena. This was the reason for a renewed and global examination of the whole distal urinary tract. The results are published in five successive papers. Our own examinations are based on 30,000 serial sections of the bladder neck taken from 65 male and female cadavers of all age groups. The muscle system of the urinary bladder consists of a network of smooth muscle cells forming three layers. Caudally the longitudinal muscle layers form two special recently described structures: the collare vesicae and nodus vesicae. None of the muscle systems of the urinary bladder leaves the spatial dimension of the organ. Simply two anatomical structures fix the urinary bladder in the pelvis. Dorsally it is the musculus vesicoprostaticus and the musculus vesicovaginalis, respectively; ventrally the existence of the musculi pubovesicales is introduced. There is no involvement of the lamellas of the bladder muscles in the formation of the urinary sphincter. Therefore the morphological substrate for a hitherto generally acknowledge contribution of the detrusor vesicae to the active continence function does not exist.