Definitions for "Fontanels"
Keywords:  fetal, skull, spots, soft, cranium
Soft spots on head of young infant. (85)
The fetal cranium contains two spaces between the bones covered by tough membranes. The anterior fontanel on the top of the head is approximately diamond shaped and does not become solid until the child reaches about two years of age. The posterior fontanel at the back of the head closes about two months after birth. The fontanels may become tense or bulge if there is a change in intracranial pressure. They may also become soft and depressed if there is any dehydration.
Membranous areas in the human cranial bones that do not form bony structures until the child is 14 to 18 months old; know as "soft spots."