Cephalic index

The cephalic index or cranial index is the ratio of the maximum width of the head of an organism (human or animal) multiplied by 100 divided by its maximum length (i.e., in the horizontal plane, or front to back). The index is also used to categorize animals, especially dogs and cats.

Use in human anthropology (Historic)

Early anthropology

The index was widely used by anthropologists in the early 20th century to categorize human populations, and by Carleton S. Coon in the 1960s. Today it is mainly used to describe individuals' appearances and for estimating the age of fetuses for legal and obstetrical reasons.

The cephalic index was defined by Swedish professor of anatomy Anders Retzius (1796–1860) and first used in physical anthropology to classify ancient human remains found in Europe. The theory became closely associated with the development of racial anthropology in the 19th and early 20th centuries, when prehistorians attempted to use ancient remains to model population movements in terms of racial categories.