Anatomy Of The Submucosal Tunnel
It is the retrograde flow of urine from the bladder into the upper urinary tract. It carries the risk of reflux nephropathy. Normally, the distal ureter passes through a submucosal tunnel, after entering the bladder, and opens into the bladder lumen. But, if the length of the submucosal tunnel or the muscular backing is inadequate, the valve does not function properly and results in reflux.