The urachus is the fibrous vestigial remnant of the fetal allantois.

The lumen of the urachus usually obliterates after birth and it becomes the median umbilical ligament, a midline linear fibrous fold of parietal peritoneum, extending from the apex of the bladder to the umbilicus.

If the lumen does not completely involute, a spectrum of urachal remnants may persist, including

A urachal remnant may develop adenocarcinoma.


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Article information

rID: 24418
System: Urogenital
Section: Anatomy
Synonyms or Alternate Spellings:
  • Median umbilical ligament

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Cases and figures

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    Normal urachus
    Figure 1: urachus - indicated by arrows
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    Case 1: prominent urachus
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