I read the craziest news story recently. We all know that babies are born with the bones of their skull separated, and that these bones fuse over time, leaving behind sutures like the pterion. The shifting bones allow the baby to fit through the birth canal.
Well, a baby was born. He seemed healthy enough, but he had had to be delivered by C-section. Doctors said his head was too big for his mother's pelvis, which historically has been really, really rare.
At his two-month checkup, the pediatrician noticed that his head just didn't look right. Turns out he had been born with all the bones in his skull prematurely fused! His brain didn't have room to grow. He received surgery and wore one of those special helmets for a while and is expected to develop normally from now on.