In the analysis of neurogenic urinary voiding disturbances, too much attention has been paid to the bladder, too little to the muscular tubing of the posterior urethra and to the pelvic floor. Contrast radiography of the urethra in injection and micturition, combined with urodynamic investigations, seemed suitable for comprehension of neurogenic functional disturbances of the posterior urethra and the pelvic floor. A cross section of 143 predominantly traumatic patients and 69 patients with myelomeningocele were investigated radiologically. In addition, in a number of patients urinary flow was determined by uroflowmetry and micturition studies with simultaneous recording of intravesical and intrarectal pressure, of the EMG-activity of the pelvic floor and urinary flow were performed by a special method. The radiologic section shows that the urinary picture of various neurogenic bladder types are characterized by specific changes in form of the posterior urethra. With the help of systematic investigations of a number of cases it was demonstrated that in automatic bladder the roentgen contour of the urethra changes with duration of illness and that primarily secondary, morphologic changes--recognizable at the same time from the increasing number of radiologically demonstrable changes of the prostate and the seminal vesicles--are responsible. Simultaneously a typical deformation of the posterior urethra in passive urinary voiding is described, and attention directed to the fact that the urinary pictures of children with neurogenic impaired urethra sometimes cannot be distinguished from those with urethral values. Urinary flow measurements show that the flow rates from a cross section of patients with lesions of the upper and lower neurons are significantly lower in comparison to normals. With the help of combined urodynamic investigations it was demonstrated that a functional obstruction was present in the neurogenic bladder at the level of spastic and of paretic pelvic floors. It was proved that the roentgenologically visible deformation of the posterior urethra plays a quite decisive role in neurogenically disturbed urinary voiding. It is the main reason why, despite sufficient bladder pressure values, urinary voiding remains unsatisfactory and urinary performance low. Hence the therapeutic consequence follows: an improvement in urinary performance in neurogenic bladder is generally only possible through a decrease in the expulsion resistance. Various operative procedures for the release of bladder outlet obstruction and their uses are discussed.