The urethral pressure profile is a manipulation test of the bladder neck, urethra, and its sphincters. It measures the balance of pressure at each point along the urethra while a small amount of distending fluid is instilled continuously. The urethral pressure profile probably represents a perfusion pressure, a minimal distension pressure, or a minimal opening pressure that is altered by the caliber of the urethra and the compliance of its walls along its proximal course. The test is meaningful when each point along the traverse is compared, in succession, with all the other points and as long as the assumption holds that changes in bladder configuration, pressure, and filling are incosequential during performance of the test.