After a bump on the head today I was feeling DS's head for any eggs, and discovered he has a ridge under his hairline right in the middle about 3 in long. This is not where he banged himself so not an injury - feels like bone. He is 13 months so still has a tiny fontanelle and the ridge comes out of that down to his forehead. DH says he looks like a klingon! Am worried there is some problem with where the bones have fused? Or is this normal?