[Observation of the posterior urethra by transrectal linear ultrasonography].

Transrectal linear ultrasonography was performed on 59 male patients with dysuria, and voiding movement of the posterior urethra was observed with a videomonitor. Uroflowmetry was performed simultaneously, and the results were compared with those obtained in a previous study. On the image synchronized with maximum flow rate, the diameter of the bladder neck, and the center of the prostatic urethra were measured as parameters and the correlation with maximum flow rate, average flow rate, and residual urine rate, was examined. The forward movement of the ventral side of the posterior urethra was found to play a more important role in the opening of the posterior urethra, than the opening of the bladder neck, and the width of the prostatic urethra to play a more important role in the efficiency of urination than the width of the bladder neck.