Brachycephaly means to have a short, broad head.
Technically, brachycephaly is defined as a skull with a
cephalic index over 80. The cephalic index is a rating
scale that is used to measure the size of the head. The
rating on the cephalic index is obtained by multiplying
the maximum width of the head by 100 and dividing that
number by the maximum length of the head. A cephalic
index between 76 and 80 is considered normal.
Brachycephaly is present since birth and is caused
when the skull is formed incorrectly. Specifically, bones
of the skull (known as coronal sutures) come together
too early, which results in the head growing out too
much to the sides.

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The coronal sutures connect the frontal (front) bone of the skull with the bone directly
behind it (the parietal bone). The growth of the head to the sides is what gives it the short
and broad appearance that it is characteristic of brachycephaly. The Native Americans
Indians, Burmese (people from Burma), and Malays (people from the Malay Peninsula),
are races of people that are characterized with brachycephaly. Compare brachycephaly
to dolichocephaly, which is a long head. A normal, medium sized head is known as
mesocephalic. There is also microcephaly (an abnormally small head) and macrocephaly
(an abnormally large head). Brachycephalic and brachycephalous means pertaining to
brachycepahly. Brachycephaly is also known as brachycephalia and brachycephalism.
Brachycephaly comes from the Greek word "brachys" meaning "short," and the Greek
word "kephale" meaning "head." Put the words together and you have "short head."

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