Morphology of umbilical vessels in human fetuses: a quantitative light microscope study

To investigate the development of the intra-abdominal part of the umbilical vessels in human fetuses by light microscopy. The location of the umbilicus and umbilical vessels in the abdominal cavity of 90 human fetuses of gestational ages 10-40 weeks was determined. The external vessel diameter, lumen diameter, wall thickness, tunica adventitia thickness, tunica media thickness and the number of vasa vasorum were recorded from cross-sectlons of the intra-abdominal part of the umbilical vessels. 1985). 1985). Umbilical artery agenesis was observed on the left side in two cases and on the right in one case. There was a positive correlation between gestational age and umbilical vessel measurements. There were differences between the vessel and lumen diameters, tunica media thicknesses of the vessels of the second and third trimesters, and the full-term period. There were also predictable differences between the vessel and lumen diameters, tunica media and tunica adventitia thicknesses of the umbilical vein and umbilical arteries. Detailed information on quantitative parameters of umbilical vessels at each gestational age may prove helpful in determining pathologies of umbilical vessels and illuminating certain syndromes.