This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth and development, Subject name: Pediatrics
Which of the following statement is true about the anterior fontanelle? 
Select and explain. 
A. Size of anterior fontanelle is about 2.5 mm x 2.5 mm, B. It normally closes at bih, C. It must be measured across the borders, D. Early closure is seen in rickets
C: It must be measured across the borders
Answer: C: It must be measured across the borders 
Explanation: Size of anterior fontanelle is 2.5 cm x 2.5 cm. It closes by 18 months. It must be measured across the borders. Delayed closure is seen in hypothyroidism, rickets, trisomy syndromes, intrauterine infections, hypophosphatasia and osteogenesis imperfecta. Ref: Clohey, 8th edition, pg no 103; Dutta Obstetrics, 8th edition, pg no 95