Apatite c-axis Orientation Tracks Disc-Mediated Local Principal Stress Directions in the Human Lumbar Vertebra.
6 affiliations
- 1Division of Materials and Manufacturing Science, Graduate School of Engineering, The University of Osaka, 2-1, Yamadaoka, Suita, Osaka, 565-0871, Japan.
- 2R&D Department, Ratoc System Engineering Co., Ltd, Tokyo, Japan.
- 3Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.
- 4Department of Orthopaedic Surgery, Osaka Orthopedic Hospital, Osaka, Japan.
- 5Department of Orthopaedic Surgery, Shiraniwa Hospital, Nara, Japan.
- 6Division of Materials and Manufacturing Science, Graduate School of Engineering, The University of Osaka, 2-1, Yamadaoka, Suita, Osaka, 565-0871, Japan. [email protected].
Abstract
Bone mechanical competence depends not only on bone mass but also on the anisotropic orientation of the collagen/biological apatite (BAp) composite, yet its relationship to the local mechanical environment in human vertebrae remains unclear. Here, we examined whether region-specific BAp c-axis orientation corresponds to predominant principal stress direction estimated by µCT-based finite element analysis. The anterior region showed predominantly uniaxial alignment along the craniocaudal axis, corresponding to a predominant principal stress direction oriented primarily along the craniocaudal axis. In contrast, the cranial and caudal subchondral regions exhibited a two-dimensional in-plane orientation pattern corresponding to predominant principal stress directions within the anteroposterior-mediolateral plane, consistent with load transfer through the intervertebral disc, which imposes transverse in-plane loading on the endplate region. At the corticotrabecular junction, the preferred BAp orientation changed markedly within a spatial range of 100 μm or less. Overall, these findings demonstrate region-specific stress-orientation correspondence in human vertebrae and support crystallographic orientation as a quantitative bone-quality indicator of vertebral mechanical adaptation.
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BibTeX
@article{mori2026apatite,
title = {{Apatite c-axis Orientation Tracks Disc-Mediated Local Principal Stress Directions in the Human Lumbar Vertebra.}},
author = {Toko Mori and Tadaaki Matsuzaka and Aira Matsugaki and Sayaka Miyabe and Nobuhito Nango and Yukihide Minoda and Hiroyoshi Iwaki and Akio Kobayashi and Takayoshi Nakano},
journal = {Calcified tissue international},
year = {2026},
month = oct,
doi = {10.1007/s00223-026-01629-0},
url = {https://europepmc.org/article/MED/42909634},
note = {CC BY},
}
RIS
TY - JOUR
TI - Apatite c-axis Orientation Tracks Disc-Mediated Local Principal Stress Directions in the Human Lumbar Vertebra.
AU - Toko Mori
AU - Tadaaki Matsuzaka
AU - Aira Matsugaki
AU - Sayaka Miyabe
AU - Nobuhito Nango
AU - Yukihide Minoda
AU - Hiroyoshi Iwaki
AU - Akio Kobayashi
AU - Takayoshi Nakano
PY - 2026
DA - 2026/10/23
JO - Calcified tissue international
DO - 10.1007/s00223-026-01629-0
UR - https://europepmc.org/article/MED/42909634
AB - Bone mechanical competence depends not only on bone mass but also on the anisotropic orientation of the collagen/biological apatite (BAp) composite, yet its relationship to the local mechanical environment in human vertebrae remains unclear. Here, we examined whether region-specific BAp c-axis orientation corresponds to predominant principal stress direction estimated by µCT-based finite element analysis. The anterior region showed predominantly uniaxial alignment along the craniocaudal axis, corresponding to a predominant principal stress direction oriented primarily along the craniocaudal axis. In contrast, the cranial and caudal subchondral regions exhibited a two-dimensional in-plane orientation pattern corresponding to predominant principal stress directions within the anteroposterior-mediolateral plane, consistent with load transfer through the intervertebral disc, which imposes transverse in-plane loading on the endplate region. At the corticotrabecular junction, the preferred BAp orientation changed markedly within a spatial range of 100 μm or less. Overall, these findings demonstrate region-specific stress-orientation correspondence in human vertebrae and support crystallographic orientation as a quantitative bone-quality indicator of vertebral mechanical adaptation.
SN - 0171-967X
SN - 1432-0827
ER -