How many blood vessels are present in the umbilical cord?How many blood vessels are present in the umbilical cord?

Appeared in: MNS 2024

Explanation

A normal umbilical cord at term contains three vessels.
These vessels are specifically two umbilical arteries and one umbilical vein.
The umbilical vein carries oxygenated blood from the placenta to the fetus.
The two umbilical arteries carry deoxygenated blood and waste products from the fetus back to the placenta.

Option A: This option incorrectly reverses the number of arteries and veins. The correct configuration is two arteries and one vein.
Option C: While the early embryo has two arteries and two veins, the right umbilical vein typically atrophies and disappears during development.
Option D: This describes an abnormal condition known as a two-vessel cord or Single Umbilical Artery (SUA), not the normal anatomy.

Clinical Relevance

Nursing practice connection: Knowing Anatomy of the Umbilical Cord helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Counting the umbilical cord vessels is a standard part of the newborn assessment in the delivery room and during prenatal ultrasound.
The presence of only two vessels (a single umbilical artery) is the most common congenital abnormality of the cord. While often an isolated finding, it can be associated with other anomalies, particularly of the cardiovascular, gastrointestinal, or genitourinary systems, and may prompt further diagnostic evaluation.
What if? If a two-vessel cord (Single Umbilical Artery) is identified, the standard of care involves a detailed fetal anatomical survey via ultrasound to screen for associated anomalies. Postnatal examination of the infant is also crucial.

How to Approach the Question

This is a factual recall question testing basic knowledge of fetal anatomy.
Identify the key terms in the question: 'umbilical cord' and 'blood vessels'.
Recall the standard anatomical structure of a mature umbilical cord.
Remember the mnemonic 'AVA' which stands for Artery-Vein-Artery, representing the two arteries and one vein.
Evaluate each option against this known fact to select the correct answer.

Concept Tested & Keywords

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E6 Obstetrics Williams p. 71-95

E6 Histology Inderbir 11e p. 5-7

Practise the full MNS 2024

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