Anterior fontanel closes by?

Appeared in: MNS 2024

Explanation

The anterior fontanel is a diamond-shaped membranous gap on an infant's skull.
Its presence allows for the rapid growth of the brain that occurs during the first year of life.
According to standard developmental milestones, the anterior fontanel typically completes its closure (ossification) by 18 months of age.
This timeline distinguishes it from the posterior fontanel, which closes much earlier.

Option A: At 6 months, the anterior fontanel is still wide open to accommodate ongoing brain growth. This is far too early for its closure.
Option B: While the process of closure may begin around this time, the fontanel is not fully closed at 10 months. It remains open to allow for continued brain development.
Option D: Closure of the anterior fontanel by 24 months (2 years) is considered delayed. If the fontanel remains open at this age, it warrants further medical investigation for potential underlying conditions such as hydrocephalus, hypothyroidism, or rickets.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Normal developmental milestones in infants, specifically the closure of the anterior fontanel as background academic context rather than a clinical decision trigger.
Nurses routinely assess the fontanels during infant check-ups. A sunken fontanel is a key clinical sign of dehydration, while a tense or bulging fontanel is a red flag for increased intracranial pressure (ICP).
Palpation of the fontanels during labor helps determine the position and degree of flexion of the fetal head as it descends through the birth canal.
Educating parents about the normal feel of a fontanel and the signs of abnormality (sunken or bulging) is an important nursing responsibility for promoting infant safety.

How to Approach the Question

First, identify the core of the question, which is asking for a specific factual detail about infant development: the closure time of the anterior fontanel.
This is a factual recall question. Access your knowledge of pediatric developmental milestones.
Recall the two main fontanels: anterior and posterior, and their respective closure times.
Remember that the anterior fontanel is larger and closes later to accommodate brain growth, while the posterior one closes very early.
Compare the given options (6, 10, 18, 24 months) to the known normal range for anterior fontanel closure (12-18 months).
Select the option that falls within or at the end of this established timeframe.

Concept Tested & Keywords

Concept Tested: Normal developmental milestones in infants, specifically the closure of the anterior fontanel.
Stem keywords: Anterior fontanel, closes by
Lead-in keywords: BEST, MOST RELEVANT CLUE
Negative lead-in flag: false

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E6 Comprehensive Textbook of Community Health NursingShyamala D part 1 (pp 26-389 of 389) p. 300-302

E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 53-66

Practise the full MNS 2024

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