Knitted skull bones
The infant skull is composed of growth plates designed to grow pushing away from each other. After 9y, the plates knit as the adult head size is reached.
Knitting up too early will form ridges & distort the shape of the skull.When this occurs, the knitted area can be released surgically as an open procedure or through a scope. I've cared for 3 in my practice in 3 decades & they have done fine.