A newborn is examined and the anterior fontanelle is noted to be wide and pulsatile. The anterior fontanelle normally closes by which age, and at which cranial landmark is it situated?
- A Closes by 18 months, situated at bregma ✓
- B Closes by 2 to 3 months, situated at lambda
- C Closes by 6 months, situated at asterion
- D Closes by 3 years, situated at pterion
Correct answer: A. Closes by 18 months, situated at bregma
Explanation
The anterior fontanelle is the diamond shaped membrane filled space at the meeting point of the coronal and sagittal sutures, which is the landmark called bregma. It is the largest fontanelle and normally ossifies by about 18 months of age. The posterior fontanelle, at lambda where the sagittal meets the lambdoid suture, closes much earlier, by 2 to 3 months, which eliminates option B.
Reference: Gray's Anatomy for Students, 4th ed.
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Written and medically reviewed by the StethoPrep medical team.