Human evolution and osteoporosis-related spinal fractures
Meghan M Cotter1, David A Loomis, Scott W Simpson
1Department of Anatomy, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America.
Plos One
|October 27, 2011
Summary
Human vertebrae are weaker and more porous than ape vertebrae, increasing fracture risk. This evolutionary difference may be linked to bipedalism adaptations.
Area of Science:
- Evolutionary medicine
- Comparative anatomy
- Biomechanics
Background:
- Osteoporosis-related spinal fractures are common in humans but rare in apes.
- Human osteoporosis risk is influenced by early adulthood bone mass and age-related bone loss.
Purpose of the Study:
- To investigate structural differences in young adult human and ape vertebral bodies.
- To determine if these differences predispose humans to vertebral fractures.
Main Methods:
- Examined T8 vertebrae from young adult humans and apes (chimpanzees, gorillas, orangutans, gibbons).
- Analyzed bone strength using finite element models.
- Assessed bone morphology and trabecular microarchitecture via micro-computed tomography.
Main Results:
- Young adult human vertebrae are weaker than ape vertebrae, even after accounting for body mass.
- Human vertebrae are larger but have lower bone volume fraction and thinner shells.
- Human vertebrae are more porous and weaker than ape vertebrae before age-related bone loss.
Conclusions:
- Human vertebral structure, characterized by larger size and reduced bone density, may predispose individuals to fractures.
- These differences are potentially linked to evolutionary adaptations, such as bipedalism.
- Age-related bone loss exacerbates fracture risk in humans compared to apes.
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