The “soft spots” of a baby’s skull are areas of incompletely ossified bones called fontanels. The bones of the skull are connected by fibrous, pliable, connective tissue at birth. The flexibility of these connections allows the skull bones to move and overlap as the infant passes through the birth canal. The fontanels begin to close about two months after birth. The largest of the fontanels, the frontal fontanel located on the top of the skull, does not close until 18 to 24 months of age.