Occipital bun is a morphological

Comparative anatomy

Comparative anatomy is the study of similarities and differences in the anatomy of organisms. It is closely related to evolutionary biology and phylogeny .-Description:...

 term used to describe a prominent bulge, or projection, of the occipital bone

Occipital bone

The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoidal in shape and curved on itself...

 at the back of the skull

Human skull

The human skull is a bony structure, skeleton, that is in the human head and which supports the structures of the face and forms a cavity for the brain.In humans, the adult skull is normally made up of 22 bones...

. The term is most often used in connection with scientific descriptions of classic Neanderthal

Neanderthal

The Neanderthal is an extinct member of the Homo genus known from Pleistocene specimens found in Europe and parts of western and central Asia...

 crania. While common among many of mankind's ancestors, primarily robust relatives rather than gracile, the protrusion is relatively rare in modern Homo sapiens.

Some scientists suspect occipital buns might correlate with the biomechanics

Biomechanics

Biomechanics is the application of mechanical principles to biological systems, such as humans, animals, plants, organs, and cells. Perhaps one of the best definitions was provided by Herbert Hatze in 1974: "Biomechanics is the study of the structure and function of biological systems by means of...

 of running. Another theory attributes them to enlargement of the cerebellum

Cerebellum

The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...

, a region of the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 which mediates the timing of motor actions and spatial reasoning.

There are still many human populations which often exhibit occipital buns. A greater proportion of early modern European

European ethnic groups

The ethnic groups in Europe are the various ethnic groups that reside in the nations of Europe. European ethnology is the field of anthropology focusing on Europe....

s had them, but prominent occipital buns even among Europeans are now relatively infrequent. They are still found fairly often among Basque

Basque people

The Basques as an ethnic group, primarily inhabit an area traditionally known as the Basque Country , a region that is located around the western end of the Pyrenees on the coast of the Bay of Biscay and straddles parts of north-central Spain and south-western France.The Basques are known in the...

, Sami

Sami people

The Sami people, also spelled Sámi, or Saami, are the arctic indigenous people inhabiting Sápmi, which today encompasses parts of far northern Sweden, Norway, Finland, the Kola Peninsula of Russia, and the border area between south and middle Sweden and Norway. The Sámi are Europe’s northernmost...

 and Finn individuals. Bushmen

Bushmen

The indigenous people of Southern Africa, whose territory spans most areas of South Africa, Zimbabwe, Lesotho, Mozambique, Swaziland, Botswana, Namibia, and Angola, are variously referred to as Bushmen, San, Sho, Barwa, Kung, or Khwe...

 from South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

 and Australian aborigines

Indigenous Australians

Indigenous Australians are the original inhabitants of the Australian continent and nearby islands. The Aboriginal Indigenous Australians migrated from the Indian continent around 75,000 to 100,000 years ago....

 often have occipital buns also.

A study conducted by Lieberman, Pearson and Mowbray provides evidence that individuals with narrow heads (dolicocephalic) or narrow cranial bases and relatively large brains are more likely to have occipital buns as a means of resolving a spatial packing problem.

External links

• PBS.org - 'Neanderthals on Trial' (January 22, 2002)