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dc.contributor.authorDeSilva, Jeremy M.en_US
dc.contributor.authorThrockmorton, Zachary J.en_US
dc.date.accessioned2012-01-12T16:41:56Z
dc.date.available2012-01-12T16:41:56Z
dc.date.issued2010-12-28
dc.identifier.citationDeSilva, Jeremy M., Zachary J. Throckmorton. "Lucy's Flat Feet: The Relationship between the Ankle and Rearfoot Arching in Early Hominins" PLoS ONE 5(12): e14432. (2010)
dc.identifier.issn1932-6203
dc.identifier.urihttps://hdl.handle.net/2144/3361
dc.description.abstractBACKGROUND. In the Plio-Pleistocene, the hominin foot evolved from a grasping appendage to a stiff, propulsive lever. Central to this transition was the development of the longitudinal arch, a structure that helps store elastic energy and stiffen the foot during bipedal locomotion. Direct evidence for arch evolution, however, has been somewhat elusive given the failure of soft-tissue to fossilize. Paleoanthropologists have relied on footprints and bony correlates of arch development, though little consensus has emerged as to when the arch evolved. METHODOLOGY/PRINCIPAL FINDINGS. Here, we present evidence from radiographs of modern humans (n=261) that the set of the distal tibia in the sagittal plane, henceforth referred to as the tibial arch angle, is related to rearfoot arching. Non-human primates have a posteriorly directed tibial arch angle, while most humans have an anteriorly directed tibial arch angle. Those humans with a posteriorly directed tibial arch angle (8%) have significantly lower talocalcaneal and talar declination angles, both measures of an asymptomatic flatfoot. Application of these results to the hominin fossil record reveals that a well developed rearfoot arch had evolved in Australopithecus afarensis. However, as in humans today, Australopithecus populations exhibited individual variation in foot morphology and arch development, and "Lucy" (A.L. 288-1), a 3.18 Myr-old female Australopithecus, likely possessed asymptomatic flat feet. Additional distal tibiae from the Plio-Pleistocene show variation in tibial arch angles, including two early Homo tibiae that also have slightly posteriorly directed tibial arch angles. CONCLUSIONS/SIGNIFICANCE. This study finds that the rearfoot arch was present in the genus Australopithecus. However, the female Australopithecus afarensis "Lucy" has an ankle morphology consistent with non-pathological flat-footedness. This study suggests that, as in humans today, there was variation in arch development in Plio-Pleistocene hominins.en_US
dc.description.sponsorshipLeakey Foundationen_US
dc.language.isoen
dc.publisherPublic Library of Scienceen_US
dc.rightsDeSilva, Throckmorton. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.en_US
dc.titleLucy's Flat Feet: The Relationship between the Ankle and Rearfoot Arching in Early Homininsen_US
dc.typeArticleen_US
dc.identifier.doi10.1371/journal.pone.0014432
dc.identifier.pmid21203433
dc.identifier.pmcid3010983


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