брахицефалия

The positional brachycephaly is a cranial deformity consisting of symmetrical flattening of the back of the head.

It’s usually seen in infants who sleep always in supine position, looking at the sky.
The head is shorter than normal, and to compensate, may be wider in the front view or higher in the back in a side view. In these cases the cranial index is high, usually between 90 and 100 or above 100 in the most severe cases.