The distribution of material properties in the equine third metacarpal bone serves to enhance sagittal bending.

The study focuses on understanding how the differing material properties in various sections of the horse’s third metacarpal bone (MC3) can potentially impact its structural mechanics, particularly in enhancing its sagittal bending.

Objective of the Research

• The primary objective of this study was to quantitatively evaluate the distribution of material properties in the equine third metacarpal bone and the potential implications of this distribution on the mechanical performance of the bone. This was done through single-load-to-failure compressive material testing on bone samples from ten horses.

Methodology

• Bone samples were extracted from six varying regions within five proximodistal levels of MC3. For testing, these samples were shaped into right cylinders and then compressed at a strain rate of 0.01 s-1.

Findings

• The research found that the material in the diaphyseal (midsection) part of the MC3 bone was stiffer, stronger, and less likely to deform compared to the metaphyseal (end sections) cortical bone material. This highlighted a key variation in material properties within the same bone.
• Additionally, it was observed that lateral and medial (side) sections of the MC3 cortical bone were stiffer and less prone to deformation under stress compared to the dorsal and palmar (front and back) materials.
• These variances in stiffness, strength, deformation, and energy absorption characteristics across different parts of the MC3 bone indicate a distribution pattern that may enhance the bone’s structural compliance in the sagittal plane (front to back).

Conclusion and Implications

• This differential distribution of material properties could potentially heighten the predictability of strain distribution during the horse’s normal movement, which is a function usually facilitated by a sagittal curvature in most bones.
• These findings have implications for understanding the biomechanics of horse locomotion and could contribute to more effective preventive strategies or treatments for equine bone disorders.