Skeletal estimates of Gigantopithecus based on a Gorilla analogy

Mandibular metrics of Gorilla gorilla are used to generate multiple regression equations using long bones metrics as criterion variables. These equations are then used to predict skeletal estimates of Gigantopithecus based upon mandibular metrics. On the average, the long bones of Gigantopithecus were 20–25% longer and more robust than those of living gorillas.     

Tail blow energy and carapace fractures in a large glyptodont (Mammalia, Xenarthra)

Glyptodonts had muscular tails terminating, in many cases, with a rigid bony sheath which, in Doedicurus and Panochthus, was a formidable club. Some carapaces show fractures which have been interpreted as resulting from intraspecific fights. We estimate the energy that the tail muscles could have supplied for a blow and the energy required to fracture the carapace, and obtain results of the same order of magnitude. Thus it is not unreasonable to interpret die observed damage as resulting from fights. A space between the thoracic and lumbar vertebral column and the carapace may have been occupied by a fatty pad which would have served as a protective cushion, reducing the force of impacts.     

Modal behaviour of bones during fracture

A common cause of human disability is related to the fracture of bones, complex structural materials whose properties vary with time. An analytical study (using ANSYS, a commercial finite element package) of bones under fracture conditions is presented, focusing on the frequency variation versus depth of crack, as well as on the evolution of strength in the fracture area.     

Functional adaptation of cancellous bone in human proximal femur predicted by trabecular surface remodeling simulation toward uniform stress state

Two-dimensional simulation of trabecular surface remodeling was conducted for a human proximal femur to investigate the structural change of cancellous bone toward a uniform stress state. Considering that a local mechanical stimulus plays an important role in cellular activities in bone remodeling, local stress nonuniformity was assumed to drive trabecular structural change to seek a uniform stress state. A large-scale pixel-based finite element model was used to simulate structural changes of individual trabeculae over the entire bone. As a result, the initial structure of trabeculae changed from isotropic to anisotropic due to trabecular microstructural changes caused by surface remodeling according to the mechanical environment in the proximal femur. Under a single-loading condition, it was shown that the apparent structural property evaluated by fabric ellipses corresponded to the apparent stress state in cancellous bone. As is observed in the actual bone, a distributed trabecular structure was obtained under a multiple-loading condition. Through these studies, it was concluded that trabecular surface remodeling toward a local uniform stress state at the trabecular level could naturally bring about functional adaptation phenomenon at the apparent tissue level. The proposed simulation model would be capable of providing insight into the hierarchical mechanism of trabecular surface remodeling at the microstructural level up to the apparent tissue level.