When does the Posterior Fontanelle close?

Appeared in: Maharashtra CHO - 2020

Explanation

The posterior fontanelle is the smaller, triangular-shaped soft spot on the back of an infant's head.
It is formed by the junction of the sagittal and lambdoid sutures.
Normal closure of the posterior fontanelle occurs within the first 1 to 2 months of life (approximately 6-8 weeks).

Option B: This timeframe is too late for the posterior fontanelle's closure and too early for the anterior fontanelle's closure.
Option C: This is the correct time frame for the closure of the anterior fontanelle, not the posterior one.
Option D: This timeframe is also associated with the closure of the anterior fontanelle, specifically the later end of the normal range.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pediatric Anatomy: Fontanelle Closure Time as background academic context rather than a clinical decision trigger.
Assessing fontanelles is a fundamental part of the neonatal and infant physical exam. It provides a non-invasive window into the infant's hydration status and intracranial pressure.
A bulging fontanelle in a calm infant is a critical finding that requires immediate medical evaluation to rule out serious conditions like meningitis, hydrocephalus, or hemorrhage.
What if a 4-month-old's posterior fontanelle is still palpable? While it typically closes by 2 months, a slight delay can be normal. However, if it remains widely open, it could indicate delayed bone maturation or increased intracranial pressure, warranting further investigation for conditions like congenital hypothyroidism or hydrocephalus.

How to Approach the Question

First, identify the key term in the question: 'Posterior Fontanelle'.
Recall the two main fontanelles: anterior and posterior. Remember that they have different shapes, locations, and closure times.
Associate 'posterior' with 'earlier'. The posterior fontanelle is smaller and closes much sooner than the anterior one.
Access your memory of the specific timeframes. The posterior fontanelle closes around 1-2 months.
Compare this with the closure time for the anterior fontanelle (9-18 months) to avoid selecting the common distractor.
Evaluate the given options and select the one that matches the correct timeframe for the posterior fontanelle.

Concept Tested & Keywords

Q52bhvMdv0Vd4lGFK5BEll

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

Practise the full Maharashtra CHO - 2020

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