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

Appeared in: DSSSB 14 August 2024

Explanation

A normal human umbilical cord contains three blood vessels: two umbilical arteries and one umbilical vein.
The two umbilical arteries are typically smaller and carry deoxygenated blood and waste products away from the fetus to the placenta.
The single, larger umbilical vein carries oxygenated, nutrient-rich blood from the placenta to the fetus.
A helpful mnemonic to remember this is 'AVA,' which stands for Artery-Vein-Artery (two arteries, one vein).
These vessels are protected from compression by a gelatinous connective tissue called Wharton's jelly.

Option A: This option reverses the correct vessel count. While the cord contains two of one type and one of the other, it is two arteries and one vein, not the other way around.
Option C: A four-vessel cord (two arteries and two veins) is a rare anomaly. It occurs when the right umbilical vein, which is present early in development, fails to atrophy and disappear.
Option D: A two-vessel cord, consisting of one artery and one vein, is the most common umbilical cord abnormality, known as a Single Umbilical Artery (SUA). It is not the normal configuration.

Clinical Relevance

Nursing practice connection: Knowing Anatomy of the umbilical cord and fetal circulation helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Assessing the number of umbilical cord vessels is a standard and important part of the newborn examination immediately after birth and during prenatal ultrasounds.
The finding of a two-vessel cord (Single Umbilical Artery) is the most common cord abnormality and serves as a clinical marker that prompts a thorough examination for associated congenital anomalies, particularly of the renal and cardiovascular systems.
What if? If a two-vessel cord is identified on a prenatal ultrasound, the nurse should anticipate that the provider may order a more detailed fetal anatomical survey and possibly a fetal echocardiogram to screen for associated defects.

How to Approach the Question

Identify the core question, which is a factual recall of anatomy: 'How many blood vessels are in a normal umbilical cord?'
Recall the basic anatomy of fetal circulation.
Use the mnemonic 'AVA' (Artery-Vein-Artery) to remember the correct count: two arteries and one vein.
Evaluate the given options based on this anatomical fact.
Eliminate options that describe anomalies (like a two-vessel or four-vessel cord) or an incorrect configuration.

Concept Tested & Keywords

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E6 Obstetrics Williams p. 71-95

E6 Ghai Essential Pediatrics(pp 26-904 of 913) p. 778-780

Practise the full DSSSB 14 August 2024

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