has part has part has_part characteristic of part of has modifier ductus venosus stenosis narrowing of ductus venosus MP:0013842 abnormal narrowing or constriction of the lumen of the embryonic connection between the portal vein and inferior vena cava formed by the left umbilical vein that allows oxygenated blood to bypass the developing liver during the time when this connection is normally open; this normally closes during develpment to adulthood abnormal ductus venosus morphology vein stenosis abnormal constricted ductus venosus