FE Fetal Cardiac Anatomy & Development 3 — Questions and Answers
Question 1: The truncus arteriosus divides into the aorta and pulmonary trunk through which process?
- Muscular septation by the interventricular septum
- Spiraling of the aortopulmonary septum (Correct answer)
- Endocardial cushion fusion
- Resorption of the bulbus cordis
Correct answer: Spiraling of the aortopulmonary septum
Neural crest–derived cells form a spiraling aortopulmonary septum that divides the truncus arteriosus into the aorta and pulmonary trunk.
Question 2: Which fetal structure preferentially directs highly oxygenated IVC blood across the foramen ovale to the left atrium?
- Crista terminalis
- Eustachian valve (valve of the inferior vena cava) (Correct answer)
- Thebesian valve
- Moderator band
Correct answer: Eustachian valve (valve of the inferior vena cava)
The Eustachian valve directs oxygenated blood from the IVC through the foramen ovale into the left atrium, supplying the brain and coronary circulation.
Question 3: At 20 weeks gestation, the normal fetal heart rate range is approximately:
- 100–120 bpm
- 120–160 bpm (Correct answer)
- 160–200 bpm
- 80–100 bpm
Correct answer: 120–160 bpm
Normal fetal heart rate at mid-gestation ranges from 120 to 160 bpm, reflecting parasympathetic and sympathetic balance at this stage.
Question 4: Which segment of the interventricular septum is derived from endocardial cushion tissue?
- Inlet (membranous) septum (Correct answer)
- Trabecular muscular septum
- Infundibular septum
- Outlet septum
Correct answer: Inlet (membranous) septum
The inlet (membranous) portion of the interventricular septum develops from fusion of the endocardial cushions.
Question 5: In the standard outflow tract view, the aorta and pulmonary artery should cross each other at approximately what angle?
- 0° (parallel)
- 45°
- 90° (Correct answer)
- 135°
Correct answer: 90°
The aorta and pulmonary artery cross at approximately 90° in the normal fetus, reflecting the spiral division of the common truncus.
Question 6: Which four-chamber view finding is most reliable for identifying the morphologic left ventricle?
- Trabeculated apex with moderator band
- Smooth-walled cavity with mitral valve attached to posterior wall (Correct answer)
- Connection to pulmonary artery
- Crescent-shaped cavity
Correct answer: Smooth-walled cavity with mitral valve attached to posterior wall
The morphologic left ventricle is smooth-walled, elliptical, and has the mitral valve attached to the posterior wall without a moderator band.
Question 7: Fetal pulmonary venous return normally drains into which cardiac chamber?
- Right atrium
- Left atrium (Correct answer)
- Left ventricle
- Coronary sinus
Correct answer: Left atrium
The four pulmonary veins drain oxygenated blood from the lungs into the left atrium, establishing normal pulmonary venous anatomy.
FE Fetal Cardiac Anatomy & Development 3
The truncus arteriosus divides into the aorta and pulmonary trunk through which process?