part_of starts_at ends_at urogenital sinus caudal urogenital sinus anatomical_structure EMAPA:30879 The caudal urogenital sinus (CUGS) (syn: primitive pelvic urethra) (TS:19-TS:20) is the posterior/caudal part of the urogenital sinus, including the urogenital sinus ridge, where the common nephric ducts/nephric ducts join the urogenital sinus. Comprised of the urogenital sinus ridge, rest of caudal urogenital sinus epithelium and surrounded by the caudal urogenital sinus mesenchyme. Becomes the pelvic urethra at TS:21, which together with the primitive bladder makes up the urogenital sinus. TS19 TS20