Assertion: umbilical vein | /r/HasSubevent | a three-vessel part
Facets:
Source sentences:
text: 3a and b) and Elastica van Gieson revealed that the umbilical cord had a four-vessel part comprising two arteries and two veins, and that the two umbilical veins then fused, resulting in a three-vessel part comprising two arteries and one vein.