This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth, Development, and Behavior, Subject name: Pediatrics
Anterior fontanelle closes at: 
Select and explain. 
A. 2-3 months, B. 4-7 months, C. 12-20 months, D. 24-30 months
C: 12-20 months
Answer: C: 12-20 months 
Explanation: c. 12-20 months(Ref: Nelson's 20/e p 2792)Anterior fontanelle is a diamond-shaped structure at the junction of the frontal and parietal bones, that is open at birth and usually measures 22cm. The average time of closure is 18 mo, but the fontanelle can dose normally as early as 9 months.