has part has part characteristic of part of has modifier Abnormality of the urachus The urachus is a vestigial embryonic structure, a canal that connects the urinary bladder of the fetus with the allantois (a structure involved in the development of the umbilical cord). During embryonic development, the lumen of the urachus is normally obliterated, transforming the urachus into a solid cord. Abnormal bladder morphology quality abnormal urachus