Anatomy In the skull all are true except A The sutures are all fibrous joints B The coronal suture separates the frontal from the parietal bones C The posterior fontanelle usually closes 18 months after birth D After middle age cranial sutures begin to ossify from cranial surface 💡 Explanation In the skull all are true except ✓ Correct Answer: C. The posterior fontanelle usually closes 18 months after birth