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Form and function of the human and chimpanzee forefoot: implications for early hominin bipedalism.
Fernández, Peter J; Holowka, Nicholas B; Demes, Brigitte; Jungers, William L.
Afiliação
  • Fernández PJ; Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794, USA.
  • Holowka NB; Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
  • Demes B; Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794, USA.
  • Jungers WL; Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794, USA.
Sci Rep ; 6: 30532, 2016 07 28.
Article em En | MEDLINE | ID: mdl-27464580
During bipedal walking, modern humans dorsiflex their forefoot at the metatarsophalangeal joints (MTPJs) prior to push off, which tightens the plantar soft tissues to convert the foot into a stiff propulsive lever. Particular features of metatarsal head morphology such as "dorsal doming" are thought to facilitate this stiffening mechanism. In contrast, chimpanzees are believed to possess MTPJ morphology that precludes high dorsiflexion excursions during terrestrial locomotion. The morphological affinity of the metatarsal heads has been used to reconstruct locomotor behavior in fossil hominins, but few studies have provided detailed empirical data to validate the assumed link between morphology and function at the MTPJs. Using three-dimensional kinematic and morphometric analyses, we show that humans push off with greater peak dorsiflexion angles at all MTPJs than do chimpanzees during bipedal and quadrupedal walking, with the greatest disparity occurring at MTPJ 1. Among MTPJs 2-5, both species exhibit decreasing peak angles from medial to lateral. This kinematic pattern is mirrored in the morphometric analyses of metatarsal head shape. Analyses of Australopithecus afarensis metatarsals reveal morphology intermediate between humans and chimpanzees, suggesting that this species used different bipedal push-off kinematics than modern humans, perhaps resulting in a less efficient form of bipedalism.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Hominidae / Pé / Articulação Metatarsofalângica Idioma: En Ano de publicação: 2016 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Hominidae / Pé / Articulação Metatarsofalângica Idioma: En Ano de publicação: 2016 Tipo de documento: Article