brachycephaly

Brachycephaly (derived from the Ancient Greek βραχύς, 'short' and κεφαλή, 'head') is the shape of a skull shorter than average in its species. It is perceived as a desirable trait in some domesticated dog and cat breeds, notably the pug and Persian, and can be normal or abnormal in other animal species. In humans, is can appear both pathologically and non-pathologically as a result of normal human variation. It is particularly common in Mongolians and the Andamanese. In anthropology, human populations have been characterized as either dolichocephalic (long-headed), mesocephalic (moderate-headed), or brachycephalic (short-headed). The usefulness of the cephalic index was questioned by Giuseppe Sergi, who argued that cranial morphology provided a better means to model racial ancestry. When pathological, it is known as flat head syndrome, and it results from premature fusion of the coronal sutures, or from external deformation. 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. This feature can also be a symptom of Down syndrome.