The accessory structure in the fetal circulation which connects the umbilical vein to the Inferior vena cava is called:

Appeared in: AIIMS Raipur NO - 2019 (Shift-1)

Explanation

The ductus venosus is the specific vascular shunt in the fetus that connects the umbilical vein directly to the inferior vena cava.
Its primary function is to allow highly oxygenated blood coming from the placenta to bypass the fetal liver's circulation.
This shunted blood then mixes with deoxygenated blood in the inferior vena cava before entering the right atrium of the heart.
This mechanism ensures that the most vital fetal organs, like the brain and heart, receive blood with the highest possible oxygen content.

Option A: The foramen ovale is an intracardiac shunt, an opening between the right and left atria. It does not connect the umbilical vein to the inferior vena cava.
Option B: The ligamentum venosum is the fibrous tissue that remains after the ductus venosus closes after birth. It is a remnant, not a functional vessel in the fetus.
Option D: The ductus arteriosus is a shunt that connects the pulmonary artery to the aorta, allowing blood to bypass the fetal lungs. It is not connected to the umbilical vein or inferior vena cava.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Fetal circulation and cardiovascular shunts as background academic context rather than a clinical decision trigger.
Understanding fetal circulation is critical for neonatal assessment, as the transition to postnatal circulation involves the closure of these shunts.
Failure of these shunts to close can lead to congenital heart defects. For example, a patent ductus arteriosus (PDA) can cause respiratory distress and requires medical or surgical intervention.
Nurses play a key role in monitoring newborns for signs of persistent fetal circulation, such as cyanosis, heart murmurs, and poor feeding, which may indicate a problem with shunt closure.

How to Approach the Question

First, identify the key anatomical structures mentioned in the question: 'fetal circulation', 'umbilical vein', and 'inferior vena cava'.
The question asks for the 'accessory structure' that connects these two vessels.
Recall the three main shunts in fetal circulation: ductus venosus, foramen ovale, and ductus arteriosus.
Systematically review the function of each shunt: The foramen ovale connects the atria, the ductus arteriosus connects the pulmonary artery and aorta, and the ductus venosus connects the umbilical vein and inferior vena cava.
Based on this, select the option that correctly identifies the structure connecting the umbilical vein to the inferior vena cava.
Differentiate between the fetal structure (ductus venosus) and its postnatal remnant (ligamentum venosum) to avoid confusion.

Concept Tested & Keywords

Concept Tested: Fetal circulation and cardiovascular shunts.
Stem keywords: fetal circulation, umbilical vein, inferior vena cava, accessory structure
Lead-in keywords: is called

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E6 Anatomy Grays 43e Vol 1 Part 2 pp. 56-58, 54-56, 57-59

Practise the full AIIMS Raipur NO - 2019 (Shift-1)

Attempt every question from this paper in a timed mock, then review the full solution for each one.