Anatomic basis of pathology of the urachus.

The urachus, derived partly from the allantoic canal, tethers the apex of the bladder to the umbilical ring. This vestigial structure, though constant in man, is formed by a whole series of embryologic mechanisms which are still controversial. Total or partial persistence of the lumen of the urachal canal, when sufficiently extensive, becomes manifested by characteristic clinical features. Moreover, it is frequently associated with malformational urogenital involvement, which must be routinely sought. The sole form of treatment consists of total surgical excision of the urachus.