title: Comparative in vivo forefoot kinematics of Homo sapiens and Pan paniscus.
abstract: The human metatarsophalangeal joints play a key role in weight transmission and propulsion during bipedal gait, but at present, the identification of when a habitual, human-like metatarsi-fulcrimating mechanism first appeared in the fossil record is debated. Part of this debate can be attributed to the absence of certain detailed quantitative data distinguishing human and great ape forefoot form and function. The aim of this study is to quantitatively test previous observations that human metatarsophalangeal joints exhibit greater amounts of dorsal excursion (i.e., dorsiflexion) than those of Pan at the terminal stance phase of terrestrial locomotion. Video recordings were made in order to measure sagittal excursions of the medial metatarsophalangeal joints in habitually shod/unshod adult humans and adult bonobos (Pan paniscus). Results indicate that the human first and second metatarsophalangeal joints usually dorsiflex more than those of bonobos. When timing of maximum excursion of the first metatarsophalangeal joint is coupled with existing plantar pressure data, the unique role of the human forefoot as a key site of leverage and weight transmission is highlighted. These results support hypotheses that significant joint functional differences between great apes and humans during gait underlie taxonomic distinctions in trabecular bone architecture of the forefoot.
authors.affiliation: Department of Evolutionary Anthropology, Duke University, P.O. Box 90383 Science Drive Durham, NC 27708-0383, USA. nicole.griffin@duke.edu
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Griffin
authors.forename: Kristiaan
authors.initials: K
authors.lastname: D'Août
authors.forename: Brian
authors.initials: B
authors.lastname: Richmond
authors.forename: Adam
authors.initials: A
authors.lastname: Gordon
authors.forename: Peter
authors.initials: P
authors.lastname: Aerts
mesh_terms: D000818:Animals; D000885:Anthropology, Physical; D001696:Biomechanical Phenomena; D005545:Forefoot, Human / Q000033:anatomy & histology / Q000502:physiology; D005684:Gait; D006801:Humans; D008124:Locomotion; D008683:Metatarsophalangeal Joint / Q000033:anatomy & histology* / Q000502:physiology*; D019974:Pan paniscus / Q000033:anatomy & histology* / Q000502:physiology; D012775:Shoes; D014741:Video Recording; D016474:Weight-Bearing / Q000502:physiology