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Abstract
Spontaneous vertebral fractures are common among humans, but not observed in apes. Differences in bone structure associated with increased fracture susceptibility among humans remain unclear. Our aim was to determine how vertebral bone compressive strength varies among apes and humans, and how bone loss affects differences in vertebral strength. QCT-based voxel finite element models derived from quantitative computed tomography (QCT) images of the thoracic vertebrae (T8) were created for apes and humans. Human vertebrae showed significantly reduced bone strength relative to apes with similar body mass (p<0.01) and bone mineral content (p<0.01). Bone loss simulations showed no significant differences in the effect of bone loss on strength among species. Our study suggests human vertebrae are weaker than ape vertebrae after accounting for bone mass, but are not more sensitive to age-related bone loss. Our results support the idea weaker vertebral bone contributes to the unique susceptibility of humans to vertebral fractures.
