Ashley S Hammond

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During the evolution of hominins, it is generally accepted that there was a shift in postcranial morphology between Australopithecus and the genus Homo. Given the scarcity of associated remains of early Homo, however, relatively little is known about early Homo postcranial morphology. There are hints of postcranial diversity among species, but our knowledge(More)
Contact areas and pressures between native patellas and a prosthetic condylar design femoral component were measured at flexion angles of 30 degrees, 60 degrees, and 90 degrees. These were compared to measurements obtained with a domed all-polyethylene patellar component. Mean native patellar contact areas were found to be fourfold greater than seen with(More)
Here we describe the pelvis from the holotype specimen of Pierolapithecus catalaunicus (IPS-21350), a middle Miocene (11.9 Ma [millions of years ago]) stem hominid from Barranc de Can Vila 1 in Abocador de Can Mata (Catalonia, Spain) for which a partial skeleton is preserved. This skeleton includes the oldest known great ape pelvic materials, which have(More)
The adaptive growth response of cartilage, or chondral modeling, can result in changes in joint and limb proportions during ontogeny and ultimately contribute to the adult form. Despite Hamrick's (1999) reevaluation of the mechanisms of chondral modeling, the process of chondral modeling remains poorly studied in animal models. Here, we characterize the(More)
Hominoids and atelines are known to use suspensory behaviors and are assumed to possess greater hip joint mobility than nonsuspensory monkeys, particularly for range of abduction. This assumption has greatly influenced how extant and fossil primate hip joint morphology has been interpreted, despite the fact that there are no data available on hip mobility(More)
Hip joint diameter is highly correlated with body size in primates and so can potentially provide important information about the biology of fossil hominins. However, quantifying hip joint size has been difficult or impossible for many important but fragmentary specimens. New three-dimensional technologies can be used to digitally fit spheres to the(More)
Variation in mechanical loading is known to influence chondrogenesis during joint formation. However, the interaction among chondrocyte behavior and variation in activity patterns is incompletely understood, hindering our knowledge of limb ontogeny and function. Here, the role of endurance exercise in the development of articular and physeal cartilage in(More)
OBJECTIVES The ability to reconstruct hip joint mobility from femora and pelves could provide insight into the locomotion and paleobiology of fossil primates. This study presents a method for modeling hip abduction in anthropoids validated with in vivo data. METHODS Hip abduction simulations were performed on a large sample of anthropoids. The modeling(More)
Human mothers wean their children from breast milk at an earlier developmental stage than do ape mothers, resulting in human children chewing solid and semi-solid foods using the deciduous dentition. Mechanical forces generated by chewing solid foods during the post-weaning period travel through not only the deciduous teeth, but also the enamel caps of the(More)
Femoral head size provides important information on body size in extinct species. Although it is well-known that femoral head size is correlated with acetabular size, the precision with which femoral head size can be estimated from acetabular size has not been quantified. The availability of accurate 3D surface models of fossil acetabular remains opens the(More)