VELOCITY OF URINE STREAM DURING FEMALE MICTURITION

A method is described for measuring simultaneously the stream velocity and volume flow rate during female micturition. From these measurements the average radius of the stream can be deduced. In measurements on one female subject stream velocities up to 300 cm sec-1 have been observed, consistent with a previous theoretical estimate (Griffiths, 1969). The mean stream radius ranged from below 0·1 cm to 0·14 cm. Similar measurements on a male subject gave values consistent with the results of Smith (1968). In the female, the variations in stream radius are correlated with the degree of psychological difficulty experienced in micturating under the experimental conditions. In the light of a simple theory of micturition hydrodynamics (Griffiths, 1969), this correlation suggests that, during micturition, an involuntary control mechanism acts near the midpoint of the urethra. © 1969 International Federation for Medical and Biological Engineering.