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Cephalic Index
The cephalic index is a rating scale that is used to
measure the size of the head, which helps determine
if it is normal is size (mesocephalic), abnormally small
(microcephaly), too large (macrocephaly), too long
(dolichocephaly), or too short and broad
(brachycephaly). It is calculated by multiplying the
maximum width of the head by 100 and dividing that
number by the maximum length of the head. The
resulting number provides a ratio of the maximum
width of the head to the maximum length of the head.
A ratio is the relationship of one quantity to another.
The maximum width of the head is defined as the
maximum width of the bones that surround the head,
above the supramastoid crest.
FEATURED BOOK: Bones: Skeletons and How They Work
The supramastoid crest is a rough, raised bone that forms the back part of the zygomatic
process. The zygomatic process is a bone that attaches to the temporal bone. The
temporal bone is a large bone forms the bottom part of the skull and is near the ears. The
maximum length of the head is technically defined as the maximum length from the most
easily noticed part of the glabella to the most easily noticed point on the back part of the
head. The glabella is a flat triangular bone between two rough, raised bones on the
forehead, near the eyebrows. The cephalic index is also known as the length-breadth
index.
"Where Medical Information is Easy to Understand"™
The cephalic index is used in anthropometry, which is the study of human body measurements. Cephalic
index comes from the Greek word "kephale" meaning "head," the Greek word "ikos" meaning "pertaining to,"
and the Latin word "index" meaning "that which points out." Put the words together and you get "pertaining to
that which points out (the) head."
