Urachus

Dr Daniel J Bell and Dr Ian Bickle et al.

The urachus (plural: urachuses or urachi ref) is the fibrous vestigial remnant of the embryonic allantois.

The lumen of the urachus usually obliterates after birth and it becomes known as the median umbilical ligament, which is covered by a midline linear fibrous fold of parietal peritoneum (called the median umbilical fold), which extends from the apex of the bladder to the umbilicus. It is located in the retropubic space.

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

A urachal remnant may transform into an adenocarcinoma.

Article information

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

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Cases and figures

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