Biology:Occipital bun
An occipital bun, also called an occipital spur, occipital knob, chignon hook or inion hook, is a prominent bulge or projection of the occipital bone at the back of the skull. It is important in scientific descriptions of classic Neanderthal crania.[1] It is found among archaic Homo species (including Neanderthals), as well as Upper Pleistocene Homo sapiens and present-day human populations.[2]
Occipital buns in Neanderthals
The occipital bun is a protuberance of the occipital bone. Its size and shape has been compared to that of a dinner roll. It is a quintessential trait of Neanderthals, though it is a trend in archaic Homo species. The true purpose of the occipital bun has not yet been defined.[3] However, some studies have found possible evolutionary purposes. In a study published in Proceedings of the Royal Society B, the occipital bun has been attributed to the enlargement of the visual cortex; this is hypothesized to be an adaptation to lower light levels found in the higher latitudes of Europe. This enlarged visual cortex also correlates with larger eyes among Neanderthals.[4] The occipital bun has also been hypothesized to function in relieving stress on the neck muscles, offsetting the weight of the Neanderthal's heavier, more robust face.[5]
Homology
A study conducted by Lieberman, Pearson and Mowbray provides evidence that individuals with narrow heads (dolichocephalic) or narrow cranial bases and relatively large brains are more likely to have occipital buns as a means of resolving a spatial packing problem. This differs from Neanderthals, who have wider cranial bases. This suggests that there is no homology in the occipital buns of Neanderthals and Homo sapiens.[6]
In addition to Neanderthals, fossilized early modern Homo sapiens of Europe have been found to have occipital buns. Many current-day modern human populations, including Sami, the bushmen of South Africa, and Indigenous Australians, have frequent occurrences of occipital buns. However, as previously mentioned, there is no evidence of homology between Neanderthals and Homo sapiens.[5]
Occipital buns in Homo sapiens
As mentioned above, fossilized early modern Homo sapiens of Europe, as well as current-day modern human populations, such as the Sámi, the bushmen of South Africa, and Indigenous Australians, have some prevalence of occipital buns. Among modern humans, there are three classes of occipital buns: type I (smooth), type II (crest form), and type III (spine form).[1] Type I has been found to be more common in women, while type III is more common in men.[7] In some cases, individuals with occipital buns experience a range of symptoms. The most common symptoms include tenderness at the back of the skull while lying down and/or when moving the neck. A surgical procedure can be done to reduce the size of the occipital bun and relieve symptoms.[1]
See also
- Bone terminology
- External occipital protuberance
- Terms for anatomical location
References
- ↑ 1.0 1.1 1.2 "Occipital spur: understanding a normal yet symptomatic variant from orthodontic diagnostic lateral cephalogram". BMJ Case Reports 2017: bcr–2017–220506. May 2017. doi:10.1136/bcr-2017-220506. PMID 28536237.
- ↑ "Occipital bunning among later Pleistocene Hominids". American Journal of Physical Anthropology 57 (1): 27–35. January 1982. doi:10.1002/ajpa.1330570106. PMID 6814258.
- ↑ "Chapter 11: Archaic Homo". Explorations: An Open Invitation to Biological Anthropology. Arlington, VA: American Anthropological Association. 2019. ISBN 978-1-931303-63-7. https://pressbooks-dev.oer.hawaii.edu/explorationsbioanth/chapter/__unknown__-16/. Retrieved 12 May 2022.
- ↑ "Neanderthals Doomed by Vision-Centered Brains" (in en). 2013-03-13. https://www.livescience.com/27850-social-brain-beat-neanderthal-vision.html.
- ↑ 5.0 5.1 "NOVA | Transcripts | Neanderthals on Trial | PBS". https://www.pbs.org/wgbh/nova/transcripts/2902neanderthals.html.
- ↑ "Basicranial influence on overall cranial shape". Journal of Human Evolution 38 (2): 291–315. February 2000. doi:10.1006/jhev.1999.0335. PMID 10656780.
- ↑ "Enlarged External Occipital Protuberance in young French individuals' head CT: stability in prevalence, size and type between 2011 and 2019". Scientific Reports 10 (1): 6518. April 2020. doi:10.1038/s41598-020-63554-y. PMID 32300156.
External links
- PBS.org - 'Neanderthals on Trial' (January 22, 2002)
 |  |
