How many fontanelles are present in a newborn?

Appeared in: RRB Staff Nurse Mumbai-2015

Explanation

A newborn's skull has a total of six fontanelles, which are soft, membrane-covered gaps between the cranial bones.
These include one anterior fontanelle (bregma), one posterior fontanelle (lambda), two sphenoidal fontanelles (anterolateral), and two mastoid fontanelles (posterolateral).
The fontanelles allow for the molding of the fetal head during birth and accommodate the rapid growth of the brain during infancy.

Option A: This is a common misconception. While there are six fontanelles in total, only the anterior and posterior ones are large and easily palpable during a clinical examination.
Option B: This number is anatomically incorrect and does not correspond to the number of fontanelles in a newborn skull.
Option D: This number is anatomically incorrect. A newborn has more than four fontanelles.

Visual 1: Diagram - A superior and lateral view of a newborn's skull, clearly labeling all six fontanelles (anterior, posterior, two sphenoidal, and two mastoid) and the surrounding skull bones.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the newborn skull and fontanelles as background academic context rather than a clinical decision trigger.
Fontanelle assessment is a key nursing skill. A sunken fontanelle can be a sign of dehydration, while a tense or bulging fontanelle in a calm infant can indicate increased intracranial pressure (ICP) from conditions like meningitis or hydrocephalus.
Nurses must palpate fontanelles gently while the infant is calm and preferably held upright, as vigorous crying can cause a normal fontanelle to feel protuberant.
Accurate measurement of head circumference at every well-child visit is essential to monitor brain growth, which is related to the status of the fontanelles and sutures.

How to Approach the Question

This is a factual recall question testing anatomical knowledge.
Identify the key terms in the question: "how many," "fontanelles," and "newborn."
Recall the anatomical structures of the neonatal skull.
Be aware of the common pitfall: confusing the total number of fontanelles (six) with the number of clinically prominent, palpable fontanelles (two).
Select the option that reflects the complete anatomical count, not just the ones commonly assessed.

Concept Tested & Keywords

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Practise the full RRB Staff Nurse Mumbai-2015

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