Endoscopic reappraisal of the morphology of congenital obstruction of the posterior urethra.

Congenital obstruction of the posterior urethra was first systematically classified by Young in 1919. Since then, no-one has seriously challenged the presence of both Type I and Type III "valves", although the presence of Type II lesions has often been disputed. A review of Young's papers and more recent anatomical studies, together with endoscopic findings in our own patients, indicates that most congenital posterior urethral obstructions are anatomically similar. Consequently, Young's classification now seems redundant.