, also known as flat-head syndrome, is a type of cephalic disorder
. This occurs when the coronal suture fuse prematurely, causing a shortened front-to-back diameter of the skull. The coronal suture is the fibrous joint that unites the frontal bone with the two parietal bones of the skull. The parietal bones form the top and sides of the skull.
Brachycephaly also describes a developmentally normal type of skull with a low cephalic index, such as in snub-nosed breeds of dog.