A preliminary modelling study on the equine cervical spine with inverse kinematics at walk.

This study developed a preliminary model of a horse’s cervical spine movement, specifically looking at vertebrae movements, with the aim of understanding the biomechanical movement. The study revealed that the range of motion in the cervical joints varied and this information could provide insight into the development of conditions like osteoarthritis.

Objective of the Research

The researchers wanted to calculate inverse kinematics based on cervical vertebral motion of a horse and develop a model which closely replicates measured neck movements. The goal was to gain insight into the biomechanics of equine neck movement and provide a source for inverse dynamics.

Methodology

• The measurements were recorded from six horses that did not have any neck pain.
• Reflective markers were placed on both sides of cervical vertebra 1, 3, and 6, as well as on the withers and hooves.
• The researchers then reconstructed the neck model from CT scans and developed the model using SIMM (Software for Interactive Musculoskeletal Modelling).
• Three degrees of motion were considered: Flexion-extension (FE), axial rotation (AR), and lateral bending (LB).
• The simulated motion was generated from the recorded motion of the skin markers.
• The differences in angular range of motion (ROM) of the joints were analyzed using paired sample t tests.

Findings

• From the model, the smallest flexion-extension ROM was in the C5-C6 joint and the largest was in the C3-C4 joint.
• The smallest axial rotation ROM was in the C5-C6 joint, and the largest AR ROM was in the atlantoaxial joint.
• The smallest lateral bending ROM was in the C5-C6 joint and the largest LB ROM was in the cervicothoracic joint.
• There were significant differences between the ROM of joints in 51 of 168 comparisons.

Conclusion of the Research

Based on the study’s findings, the researchers concluded that the results provide insight into the biomechanics of the equine neck. Furthermore, the small FE ROM at the C5-C6 joint indicates potential for the development of osteoarthritis, highlighting the model’s relevance to pathogenesis. The data also serves as a source for calculating inverse dynamics, allowing for further study on the biomechanics of equine neck motion.