Editing Cephalic index (section)

{{short description|Ratio of width to length of the head of an organism}}
{{distinguish|encephalization}}
{{Use dmy dates|date=February 2021}}
[[File:Cephalic index.svg|thumb|Cephalic index viewed from above the head]]
The '''cephalic index''' or '''cranial index''' is a number obtained by taking the maximum width ([[biparietal diameter]] or BPD, side to side) of the head of an [[organism]], multiplying it by 100 and then dividing it by their maximum length ([[occipitofrontal diameter]] or OFD, front to back). The index was once used to categorize human beings in the first half of the 20th century, but today it is used to categorize dogs and cats.