A study of the anatomic features of the duct of the urachus

Abstract

The urachus is an embryonic remnant resulting from involution of the allantoic duct and the ventral cloaca. Attaching the bladder dome to the umbilicus, this duct becomes progressively obliterated during fetal life. It may subsequently persist as different variants after birth, some regarded as normal, others as pathologic, due to incomplete closure. Six pediatric cases are reported here, and the literature on the embryology and anatomic basis of the duct is discussed. The urachus is present in nearly 100% of children at birth, with several possible shapes: tubular, fusiform or funnel. It gradually regresses and is found in only a third of adults. Its length varies from 1 to 15 cm. In our series 6 patients showed defective closure of the duct, including 3 with complete patency, 1 cyst, 1 diverticulum and 1 external sinus. Although rare, congenital pathology of the urachus requires a sound knowledge of the anatomy and embryology to distinguish normal forms from those subject to complications. It should be suspected with any lesion in the umbilical region and the appropriate treatment instituted.

Predictors of survival from urachal cancer

“…[10][11] The urachus is the embryonic remnant of the involution of the allantois and the ventral cloaca. [10][11][12][13] During early embryonic development (Days 16 to 24), the allantois, which is derived from the vitelline sac, opens into the upper part of the ventral or anterior cloaca forming the allantois channel. 11 By Week 5, the bladder is formed from the medial part of the allantois, and the rest, or the cloaca, narrows into a channel forming the urachus.…”

Investigation and management of suspected urachal anomalies in children

“…Although its origin is a subject of argument, most accept that both the allantois and the cloaca contribute to the urachus, with a greater contribution from the latter [1,2,12]. As the bladder descends into the pelvis, the urachal cord stretches and finally obliterates leaving a fibrous cord-like structure called the median umbilical ligament [1,2,12,13]. This process completes at 4-5 months of intrauterine life.…”

“…This process completes at 4-5 months of intrauterine life. Persistence of this structure or part of it after birth may cause symptoms prompting medical review [2,13].…”

A case of vesicourachal diverticulum containing calculus: MDCT urography findings

“…Understanding the anatomy and embryology of urachal cysts and remnants is critical in making the correct diagnosis and choosing an effective management strategy, which can avoid the complications of intraperitoneal rupture, or subsequent malignancy (1)(2)(3)(4).…”

“…However, persistence of an embryonic urachal remnant can give rise to various clinical problems, not only in infants and children but also in adults. Because urachal remnant anomalies are uncommon and manifest with nonspecific symptoms, definitive presurgical diagnosis is not easily made (1)(2)(3)(4)(5).…”