Vertical section of bladder, penis, and urethra. Urachus is seen at top
Illu quiz bladder 01.jpg
Urachus is #1
Anatomical terminology

The urachus is a fibrous remnant of the allantois, a canal that drains the urinary bladder of the fetus that joins and runs within the umbilical cord.[1] The fibrous remnant lies in the space of Retzius, between the transverse fascia anteriorly and the peritoneum posteriorly.


The part of the urogenital sinus related to the bladder and urethra absorbs the ends of the Wolffian ducts and the associated ends of the renal diverticula. This gives rise to the trigone of the bladder and part of the prostatic urethra.

The remainder of this part of the urogenital sinus forms the body of the bladder and part of the prostatic urethra. The apex of the bladder stretches and is connected to the umbilicus as a narrow canal. This canal is initially open, but later closes as the urachus goes on to definitively form the median umbilical ligament.

Other Languages
العربية: سرر مثاني
azərbaycanca: Uraxus
Deutsch: Urachus
español: Uraco
français: Ouraque
italiano: Uraco
қазақша: Урахус
日本語: 尿膜管
polski: Moczownik
português: Úraco
русский: Урахус
српски / srpski: Urahus