Fetal Veins, Portal vein formation, Derivatives of the embryonic veins - NEET PG Anatomy
Feb 17, 2023
Knowledge of Fetal Veins, Portal vein formation, and Derivatives of the embryonic veins is important for understanding the development and anatomy of various organs and structures in the body. This knowledge is crucial in making a correct diagnosis and determining appropriate treatment options for various medical conditions. Additionally, questions related to these topics are commonly asked in the NEET PG exam, making it essential for medical students to have a thorough understanding of these concepts.
Right anterior cardinal vein later contributes to form the SVC.
Left anterior cardinal vein regresses.
Posterior cardinal vein
It drains the body below the diaphragm.
Right posterior cardinal vein later contributes to form the IVC.
Left posterior cardinal vein regresses.
Anterior and posterior cardinal veins on either side join to form the right and left common cardinal veins.
3 veins each draining into the right and left horn of the sinus venosus:
Common cardinal vein
Umbilical veins are coming from the placenta. Later in the fetal circulation, the right umbilical vein regresses and only the left umbilical vein is left.
The persisting left umbilical vein in the fetal circulation also degenerates and forms ligamentum teres of the liver (having no function at all).
Vitelline veins drain the yolk sac, which forms the gut tube.
The right and left vitelline veins are passing through the septum transversum.
The septum transversum breaks the vitelline veins into right and left hepatic-cardiac channels.
Right hepatic-cardiac channel later contributes to form the terminal part of the IVC, which carries the blood from the liver towards the heart.
Right vitelline vein (along with some contribution from the left vitelline vein) forms the portal vein.
Persisting left anterior cardinal vein → leads to double SVC. Persisting left posterior cardinal vein → leads to double IVC. Septum transversum is a structure developing in the mesenchyme. It later contributes to the central tendon of the diaphragm and connective tissue of the liver.
Here, we can see that the yolk sac has developed into a gut tube (duodenum) with the right and left vitelline veins running on either side.
Portal vein contribution:
Right vitelline vein (major contribution).
Dorsal anastomosis between the right and left vitelline vein.
Left vitelline vein (minor contribution)
The portal vein passes behind the 1st part of duodenum to form the right & left branch of the portal vein inside the liver (at porta hepatis).
In fetal circulation, the left umbilical vein is connected to the IVC directly via ductus venosus. This is important as it bypasses the liver. This way the oxygen carried by the left umbilical vein can straight away enter the circulation and not go through the liver, because the fetal liver is immature.
To study this topic in detail, download the PrepLadder app and get access to engaging video lectures by India’s top medical faculty, Dr Rajesh Kaushal.
Get access to all the essential resources required to ace your medical exam Preparation. Stay updated with the latest news and developments in the medical exam, improve your Medical Exam preparation, and turn your dreams into a reality!