part_of starts_at ends_at epithelium of dorsal pelvic urethra of female urogenital sinus ridge of female The urogenital sinus ridge of female (UGS ridge) (TS:23-23) is part of the epithelium of pelvic urethra of female (TS:23). The thickened and raised, dorsal portion of the epithelium of dorsal pelvic urethra of female located at the site where the nephric and paramesonephric ducts join the pelvic urethra. Derived from the urogenital sinus ridge, part of the pelvic urethra (TS:21-TS:22) (derived from cloacal endoderm). In females, the urogenital sinus ridge blocks the originally patent opening of the nephric ducts to the urethra, and assists in the caudal migration of the paramesonephric ducts and later the vagina, towards the clitoris. It may be a source of inductive signals regulating vaginal outgrowth. At TS:24, it becomes the sinovaginal bulb (syn: vaginal bulb, lower vagina, sinus vagina). anatomical_structure EMAPA:36108 TS23