BACKGROUND Several studies showed instantaneous axis of rotation (IAR) in the intact spine. However, there has been no report on the trajectory of the IAR of a damaged spine or that of a fixed spine with instrumentation. It is the aim of this study to investigate the trajectory of the IAR of the lumbar spine using the vertebra of deer. METHODS Functional spinal units (L5-6) from five deer wer...

Bending, in addition to compression, is recognized to be a common loading pattern in long bones in animals. However, due to the technical difficulty of measuring bone deformation in humans, our current understanding of bone loading patterns in humans is very limited. In the present study, we hypothesized that bending and torsion are important loading regimes in the human tibia. In vivo tibia se...

PURPOSE The electron beam melting (EBM) Ti-6Al-4V material technology has been developed over a short time period. It was introduced through a research to develop Ti-6Al-4V implants for patients, but EBM printed locking compression plates have not been used for clinical implants. The main purpose of this study is to find whether the EBM Ti-6Al-4V plate suit for clinical implants. METHODS Firs...

A stochastic model of hierarchical series system type for the bending strength of spruce beams is defined from the anticipation that the bending failure takes place at a cross-section with a defect cluster formed by knots or grain irregularities. The parameters of the model are estimated from measurements of the strengths of a large number of short test pieces cut from the beams such that judge...

Objective: The purpose of this study was to investigate the effects of lumbar rotational manipulation and lumbar central posteroanterior mobilization on lumbar bending stiffness and flexion and extension range of motion (ROM). Methods: A samesubject, repeated-measures, crossover design was used using 32 asymptomatic subjects (16 female and 16 male; mean [SD] age, 25.5 [4.5] years; weight, 65.7 ...

Whole bone bending tests are commonly used in mechanical evaluation of long bones. Reliable information about the midshaft can only be obtained if the bending moment is uniformly distributed along the shaft, and if the distribution of the bending stress is not adversely influenced by rigid clamping of the bone ends. A testing device was developed to determine bending stiffness of long bones in ...