ABSTRACT
The definition of urinary tract obstruction is a restriction to the flow of urine that gives rise to symptoms or threatens renal function. It may occur at any point from the minor calyces of the kidney to the external meatus of the urethra. It may be acute or chronic, complete or incomplete, upper or lower urinary tract depending on its origin in relation to the vesico-ureteric junction. Upper and lower urinary tract obstruction present different clinical issues and are therefore best considered separately. It is important, however, not to overlook the interaction between the upper and lower urinary tract, which is central to understanding the dynamics of the system as a whole.
