The bladder is a hollow organ in the lower abdomen that stores urine. When the bladder is full and needs to empty, it will contract or squeeze. The sphincter muscle, or the “bladder door,” will relax and open. Urine will then flow smoothly out of the bladder. This is how the bladder empties.  

When a child is unable to relax the sphincter muscle, the urine stream will be very weak. As a result, the bladder will not empty completely and the child will develop dysfunctional voiding. Symptoms of dysfunctional voiding include urinary tract infections, urinary frequency, urgency and wetting accidents.