Canalization of the Urethral Plate Precedes Fusion of the Urethral Folds during Male Penile Urethral Development: The Double Zipper Hypothesis

摘要

Purpose: We describe the "double zipper" mechanism of human male urethral formation, where the distal zipper opens the urethral groove through canalization of the urethral plate, and a second closing zipper follows behind and closes the urethral groove to form the tubular urethra.