Editing Scoliosis (section)

===Evolution===
[[File:Abnormal bone growth.jpg|thumb|upright|A 14–15th-century woman who had severe scoliosis, and died at about 35 years, Limburgs Museum, [[Venlo]]]]

There are links between human spinal morphology, bipedality, and scoliosis which suggest an evolutionary basis for the condition. Scoliosis has not been found in [[chimpanzee]]s or [[gorilla]]s.<ref name="Lovejoy OC 2005">{{cite journal | vauthors = Lovejoy CO | title = The natural history of human gait and posture. Part 1. Spine and pelvis | journal = Gait & Posture | volume = 21 | issue = 1 | pages = 95–112 | date = January 2005 | pmid = 15536039 | doi = 10.1016/s0966-6362(04)00014-1 }}</ref> Thus, it has been hypothesized that scoliosis may actually be related to humans' morphological differences from these apes.<ref name="Lovejoy OC 2005"/> Other apes have a shorter and less mobile lower spine than humans. Some of the [[lumbar vertebrae]] in ''[[Pan (genus)|Pan]]'' are "captured", meaning that they are held fast between the [[Ilium (bone)|ilium]] bones of the pelvis. Compared to humans, [[Old World monkey]]s have far larger [[erector spinae muscles]], which are the muscles which hold the spine steady.<ref name="Lovejoy OC 2005"/> These factors make the lumbar spine of most primates less flexible and far less likely to deviate than those of humans. While this may explicitly relate only to lumbar scolioses, small imbalances in the lumbar spine could precipitate thoracic problems as well.<ref name="Lovejoy OC 2005"/>

Scoliosis may be a byproduct of strong selection for [[bipedalism]]. For a bipedal stance, a highly mobile, elongated lower spine is very beneficial.<ref name="Lovejoy OC 2005"/> For instance, the human spine takes on an S-shaped curve with [[lumbar lordosis]], which allows for better balance and support of an upright trunk.<ref>{{cite book| vauthors = Harcourt-Smith WE |title=Handbook of Paleoanthropology|year=2007|publisher=Springer Berlin Heidelberg|chapter=Chapter 5|pages=1483–1518}}</ref> Selection for bipedality was likely strong enough to justify the maintenance of such a disorder. Bipedality is hypothesized to have emerged for a variety of different reasons, many of which would have certainly conferred fitness advantages. It may increase viewing distance, which can be beneficial in hunting and foraging as well as protection from predators or other humans; it makes long-distance travel more efficient for foraging or hunting; and it facilitates terrestrial feeding from grasses, trees, and bushes.<ref>{{cite journal| vauthors = Hunt KD |title=The evolution of human bipedality: ecology and functional morphology|journal=Journal of Human Evolution|date=March 1994|volume=26|issue=3|pages=182–202|doi=10.1006/jhev.1994.1011|bibcode=1994JHumE..26..183H }}</ref> Given the many benefits of bipedality which depends on a particularly formed spine, it is likely that selection for bipedalism played a large role in the development of the spine as we see it today, in spite of the potential for "scoliotic deviations".<ref name="Lovejoy OC 2005"/> According to the fossil record, scoliosis may have been more prevalent among earlier hominids such as ''[[Australopithecus]]'' and ''[[Homo erectus]]'', when bipedality was first emerging. Their fossils indicate that there may have been selected over time for a slight reduction in lumbar length to what we see today, favoring a spine that could efficiently support bipedality with a lower risk of scoliosis.<ref name="Lovejoy OC 2005"/>