cephalic index(redirected from index, cephalic)
Also found in: Dictionary, Thesaurus, Medical.
cephalic index(səfăl`ĭk) [Gr. kephale=head], ratio of the breadth of the head to its length. Expressed as a percental number, it provides the simplest description of the geometric relation of two dimensions. The index is obtained by dividing the maximum width of the cranium by its maximum length and multiplying by 100. In anthropometryanthropometry
, technique of measuring the human body in terms of dimensions, proportions, and ratios such as those provided by the cephalic index. Once the standard approach to racial classification and comparing humans to other primates, the technique is now used for deciding
..... Click the link for more information. , the cephalic index has been the favored measurement. A cephalic index of 80 or more is called brachycephalic or broad; a measurement between 75 and 80 is mesaticephalic; below 75 is considered dolicocephalic or long. The cranial index is the same ratio taken on a skull.
index, cephalic:see cephalic indexcephalic index
[Gr. kephale=head], ratio of the breadth of the head to its length. Expressed as a percental number, it provides the simplest description of the geometric relation of two dimensions.
..... Click the link for more information. .
the ratio of the head’s greatest breadth (transverse diameter) to its greatest length (longitudinal diameter), expressed in percent.
The cephalic index is used in anthropology for determining the head contour in the horizontal plane. When the index is under 74.9 it is called dolichocephalic; between 75.0 and 79.9, mesaticephalic; and above 80.0, brachycephalic. With the aid of the cephalic index, local anthropological types can be isolated within the major races of man. Group variations in cephalic index are already reflected in early childhood. In comparison with earlier times, there has been an increase since the Middle Ages in the cephalic index (brachycephali-zation), although a decrease in the index (debrachycephaliza-tion) was recorded at a number of locations between 1950 and 1970. The cephalic index is not related to intellect.
V. P. CHTETSOV
in anthropology, the degree of protuberance of the face and the parts of the face in a vertical or horizontal plane. A vertical cephalic index is characterized by the facial angle, by the angle of the nasal portion of the face, or by the angle of the alveolar portion of the face.
A face is classified according to its facial angle. Thus, a prognathous face has an angle up to 79.9°, a mesognathous face has an angle of 80.0° to 84.9°, and an orthognathous face has an angle of 85° or more. A horizontal cephalic index determines facial flatness at the level of the root of nose; it also determines the degree of protuberance of the cheekbones. Cephalic indexes are good racial indicators.