The
cephalic index
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 diame ...
of a
vertebrate
Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain.
The vertebrates make up the subphylum Vertebra ...
is the ratio between the width (side to side) and length (front to back) of its
cranium
The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate.
In the human, the skull comprises two prominent ...
(skull). This ratio does not concern the
muzzle or face, and thus is distinct from the ''craniofacial ratio'', which compares the size of the cranium to the length of the muzzle. The two measures are often confused in descriptions of
dog breed
A dog breed is a particular type of dog that was purposefully bred by humans to perform specific tasks, such as herding, hunting, and guarding. Dogs are the most variable mammal on Earth, with artificial selection producing upward of 360 globall ...
s.
The cephalic index is used to classify animals into three groups:
Brachycephalic
Brachycephaly (derived from the Ancient Greek '' βραχύς'', 'short' and '' κεφαλή'', 'head') is the shape of a skull shorter than average in its species. It is perceived as a cosmetically desirable trait in some domesticated dog and ...
(literally 'short-headed'): the length of the cranium is shorter than the width, giving the top and sides of the cranium a round shape, often referred to as 'apple-head'.
File:Chihuahua 01 K.jpg
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Mesaticephalic or mesocephalic ('middle-headed'): the length and width are equal, giving a square shape. When dealing with animals, especially dogs, the more appropriate and commonly used term is not "mesocephalic", but rather "mesaticephalic", which is a ratio of head to nasal cavity.
[Retrieved from http://medical-dictionary.thefreedictionary.com/mesaticephalic.]
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File:American Shorthair.jpg
Dolichocephalic
Dolichocephaly (derived from the Ancient Greek δολιχός 'long' and κεφαλή 'head') is a term used to describe a head that is longer than average relative to its width. In humans, scaphocephaly is a form of dolichocephaly.
Dolichoceph ...
('long-headed): the length is greater than the width.
File:Kufa charta - borzoja.jpg
File:Savannah Cat closeup.jpg
Breeds of each group are listed in
Cephalic index
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 diame ...
.
See also
*
Artificial selection
Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant ...
*
Brachycephalic airway obstructive syndrome
Brachycephalic obstructive airway syndrome (BOAS), also known as brachycephalic airway obstructive syndrome (BAOS), brachycephalic airway syndrome (BAS), and brachycephalic syndrome (BS), is a pathological condition affecting brachycephalic, sho ...
References
{{Reflist
* Sparks, Corey S.; Jantz, Richard L. (November 2002). ''A Reassessment of Human Cranial Plasticity: Boas revisited''.
* ''Merriam Webster's New Collegiate Dictionary''
Animal anatomy
Biological anthropology