**Chapter 8** The Hepatic Fetal Venous System

*Dominic Gabriel Iliescu, George-Lucian Zorila, Roxana Cristina Dragusin, Marius Cristian Marinas, Maria Cristina Comanescu, Alexandru Cristian Comanescu, Pana Razvan Cosmin, Ovidiu Costinel Sîrbu, Sidonia Catalina Vrabie, Sidonia Maria Sandulescu and Rodica Daniela Nagy*

## **Abstract**

The vascular architecture of the human liver is established at the end of the 10th week of gestation as a result of a complex process. Recent developments in ultrasonographic imaging facilitate the prenatal evaluation of this system. However, many of the involved mechanisms are poorly understood. The hepatic primordium is in contact with the vitelline veins and the umbilical veins, and by the end of the 6th week, the afferent venous system of the liver is acquired giving rise to the portal vein, the portal sinus, and the ductus venosus. The only afferent vein of the liver that remains open at birth is the portal vein. Also, the efferent venous system of the liver is formed and emerges from the vitelline veins.

**Keywords:** fetal venous system, embryology, hepatic vasculature, liver vascular anatomy, ultrasonography

## **1. Introduction**

Intensive research has been done in the evaluation of the fetal venous system to recognize the normal and abnormal sonographic appearance. Furthermore, prenatal diagnosis of fetal venous system anomalies requires knowledge of its embryology and physiology. The information currently available regarding the etiology, importance, and prognosis of these abnormalities enables caregivers to provide appropriate parental counseling when an anomaly is encountered. Still, the sonographic evaluation of the fetus's venous system remains largely undetermined and needs more studies.
