One of the most important facets in the diagnostic work-up of a patient with urinary tract difficulty is the evaluation of the act of micturition. The significance of abnormalities in micturition can be readily comprehended when one realizes that most urinary tract infections,1urinary incontinence, and many cases of pyelonephritis and hydronephrosis are due to dysfunction of the urethra and bladder. In order to pinpoint the cause of a given urinary tract disorder it is necessary to perform (in addition to obtaining the complete history and giving a physical examination at admission) cystoscopy, urethroscopy, pyelography, cystourethrography, urethral calibration, and cystometry. A urological examination without cystometry is disquietingly incomplete, for some entities can be diagnosed only with the use of the cystometer, such as lesions of the corticoregulatory tracts leading to pollakiuria, urgency, enuresis, and urinary tract infection1; or sacral spinal-cord defects resulting in partial or complete urinary retention,