In other species: dog , domestic cat , Grevy's zebra , domestic horse , white rhinoceros , sheep

Categories: Embryo phene

Single-gene trait/disorder: unknown

Disease-related: yes

Cross-species summary: The urachus is a canal present in the foetus, connecting the bladder with the allantois via the navel. It normally disappears after birth. A patent urachus is one which persists after birth, allowing urine to drip out of the bladder through the umbilicus.