The part of fetal circulation which becomes fossa ovalis after birth?

Appeared in: KPSC Staff Nurse - 2018

Explanation

The foramen ovale is an essential opening in the fetal heart septum between the right and left atria.
Its primary function is to shunt oxygenated blood from the right atrium directly to the left atrium, bypassing the pulmonary circulation.
After birth, increased pulmonary blood flow raises the pressure in the left atrium, causing a flap to close the foramen ovale.
The remnant of this closed foramen ovale in the adult heart is a depression called the fossa ovalis.

Option A: The umbilical arteries carry deoxygenated blood away from the fetus to the placenta. After birth, their proximal parts become the superior vesical arteries, and the distal parts become the medial umbilical ligaments.
Option B: The ductus arteriosus is a blood vessel connecting the pulmonary artery to the aorta, which also bypasses the fetal lungs. After birth, it constricts and becomes the ligamentum arteriosum.
Option D: The umbilical vein carries oxygenated blood from the placenta to the fetus. After birth, it closes and becomes the ligamentum teres hepatis (round ligament of the liver).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Postnatal changes in fetal circulatory structures as background academic context rather than a clinical decision trigger.
A failure of the foramen ovale to close properly after birth results in a condition called Patent Foramen Ovale (PFO).
While often asymptomatic, a PFO can increase the risk of a paradoxical embolism, where a blood clot from the venous system passes to the arterial system, potentially causing a stroke.
Nurses should be aware of the signs of PFO-related complications, especially in patients with a history of cryptogenic stroke.

How to Approach the Question

First, identify the core concept of the question, which is the transformation of fetal circulatory structures after birth.
Recognize the key terms: 'fetal circulation', 'fossa ovalis', and 'after birth'.
This is a factual recall question. Access your knowledge of fetal anatomy and physiology.
Systematically review the three main fetal shunts: foramen ovale, ductus arteriosus, and ductus venosus.
Recall the postnatal remnant for each structure.
Match the 'fossa ovalis' with its fetal precursor, which is the 'foramen ovale', to select the correct option.

Concept Tested & Keywords

Qvp3HA7utAht1zMrhQ-CLB

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 523-525

E6 Anatomy Grays 43e Vol 1 Part 2 p. 56-58

Practise the full KPSC Staff Nurse - 2018

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