Morphometry, variations, and histogenesis of umbilical vein, portal sinus, and ductus venosus in human fetal liver: an anatomical study.

Purpose: Anatomical research on fetal liver venous systems is scarce. This study presents variations, morphometric, and histogenesis data through cadaveric study which can aid prenatal radiological analysis.

Materials and methods: 10% formalin embalmed 16 fetuses (8-second trimester, 8-third trimester) were utilized. Morphometric and histological evaluation of the umbilical vein, portal sinus, and ductus venosus were done. Variations were noted. Descriptive statistics, ratio, correlation, and regression were used for data analysis.

Result: A positive correlation of morphometric variables with gestational age is observed. An intra-hepatic portal shunt is observed connecting the left hepatic vein and portal sinus. In one case ductus venosus arose from the medial end of portal sinus and is not in continuity with the umbilical vein. Umbilical and portal sinus presents tunica intima, tunica media, and adventitia. There is an increase in smooth muscle fibers in tunica media from the second to third trimester. Ductus venosus consists of three parts- inlet, outlet, and isthmus. The wall of ductus venosus showed tunica intima and tunica adventitia.

Conclusion: This study records the variations of the umbilical vein, portal sinus, and ductus venosus. Knowledge of variations, morphometry, and histogenesis of these veins is essential to distinguish clinical variations from conditions such as agenesis of ductus venosus, persistence of the right umbilical vein, and congenital portal-systemic shunts.