The portal sinus is an L-shaped venous confluence in the fetal circulation. It is located in the liver, between the left and right intrahepatic portal veins. The umbilical vein drains into the portal sinus at its medial aspect, near the left inferior intrahepatic portal vein 1,2. The ductus venosus then drains blood entering the portal sinus from the umbilical vein superiorly into the confluence of the hepatic veins into the inferior vena cava.
The portal sinus should be visible on axial images in the second-trimester obstetrical ultrasound during measurement of the abdominal circumference 3,4 .
- 1. E. Mavrides, G. Moscoso, J. S. Carvalho, S. Campbell, B. Thilaganathan. The anatomy of the umbilical, portal and hepatic venous systems in the human fetus at 14–19 weeks of gestation. (2001) Ultrasound in Obstetrics and Gynecology. 18 (6): 598. doi:10.1046/j.0960-7692.2001.00581.x - Pubmed
- 2. Paula J. Woodward, Anne Kennedy, Roya Sohaey. Diagnostic Imaging: Obstetrics. (2016) ISBN: 9780323392563
- 3. Barbara S. Hertzberg, William D. Middleton. Ultrasound. (2015) ISBN: 9780323086189
- 4. Gianluigi Pilu, Kypros Nicolaides, Renato Ximenes, Philipe Jeanty. The 18-23 weeks scan: Diploma in Fetal Medicine & ISUOG Educational Series. (2002) International Society of Ultrasound in Obstetrics & Gynecology and Fetal Medicine Foundation, London. Fetal Medicine Foundation