Anatomical development of the normal urachus during the fetal period

OBJECTIVE: To evaluate the development of the normal urachus during the fetal period.

METHODS: The study was carried out on 149 human fetuses (male 87, female 62) aged between 9-40 weeks, obtained with families' consent from Isparta Maternity and Children's Hospital, Isparta, Turkey, between 1997 and 2002. The study was carried out in the Department of Anatomy, Faculty of Medicine, Suleyman Demirel University, Isparta, Turkey during 2004. The type of the urachus was assessed and was classified. The length, antero-posterior depth, and the transverse width of the urachus were measured. Finally, the relationship between the urachus and umbilical arteries was evaluated during the fetal period, whether they ran parallel to each other.

RESULTS: Two types of urachus were observed: the inverted funnel (84%) and tubular (16%). The length, depth, and width of the urachus increased with gestational ages in all cases. A 2% variation was observed in the neighborhood between urachus and umbilical artery.

CONCLUSION: Comparing our results with previous studies, the development of the urachus can be different in neonates and children. The mean urachus length was 14.8 -/+ 7.7mm during this period. The inverted funnel type is the most common type in our study. Hence, there can be some differences in the relationship between the urachus and umbilical arteries. The data obtained in the present study can be used as base knowledge related to the development of the urachus, and for evaluating the urachus in utero pediatric urology, radiology, pediatric surgery, and fetopathology.