Different fibrillar architectures coexisting in Haversian bone.

The research focuses on the varying structures of compact bone, primarily in horses, and their relationship with different types of stress. It was observed that different architectural structures coexist within the same bone and these structures vary based on the intensity and type of mechanical force exerted on them.

Methodology Used in the Research

• The research was primarily conducted on equine bone samples. These samples were deproteinated using heat treatment and then analyzed using Scanning Electron Microscopy (SEM).
• The heat treatment was done to effectively remove the cells and vascular structures and make the mineralization front along the Havers canal more visible.

Observations from the Research

• It was observed that compact bone subjected to high tensile stress (force that stretches or elongates an object) had collagen fibrils that were largely aligned in the direction of the stress. In such cases, the majority of the osteons (cylindrical structures within the bone) were composed of almost parallel fibrils which crossed at very narrow angles.
• On the contrary, in bones predominantly subjected to compressive forces (forces that squeeze or compress an object), the collagen lamellae showed an orthogonal alternation, or a multi-directional arrangement. This multi-directional arrangement was similar to the ‘twisted plywood’ structure described in earlier studies.

Conclusions from the Research

• The findings from this research reinforce the classical concept of osteon structure and the ‘twisted plywood’ model. It shows that several osteon architectures coexist within the same specimen.
• Additionally, the research found that the different structures are primarily distributed in different parts of the same bone. This suggests that the distribution of osteon ultrastructure across the bone matrix is influenced by mechanical factors such as the types and magnitude of forces exerted on them.