Location of maximum intraurethral pressure related to urogenital diaphragm in the female subject as studied by simultaneous urethrocystometry and voiding urethrocystography.

The urethral pressure profiles were recorded by microtransducers in 25 continent female subjects. From the recordings, the urethral length and the site of maximum intraurethral pressure were determined with a high degree of precision. The urethral length and the distance from the external urethral meatus to the urogenital diaphragm were also assessed on 100 mm roentgenograms taken in the lateral projection. When the results from both recording techniques were compared, the urogenital diaphragm was found to be located, on average, 5.2 mm more distal in the urethra than the site of the maximum urethral pressure. Thus, the conclusion to be drawn is that the high-pressure zone of the urethra in continent women is located proximal to the urogenital diaphragm.