Fig. 12
External genitalia formation. a Week 10: female differentiation is already apparent. The superficial urogenital sinus-genital folds complex primordium originates the genital tubercle and cloacal folds; b Week 12: the urethral folds arise from the cloacal folds and the urethral groove from the cloacal membrane; c Week 14: compartments are already formed. Dark green: Inner (vestibular) compartment, composed of the clitoris, urethral meatus, vestibular bulbs, greater vestibular glands, and hymen. Intermediate green: Middle (Glans/labial) compartment, containing the labia minora. Light green: Outer (interlabial) compartment, comprising the interlabial sulcus [1, 13, 14]