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

Abstract

SummaryReason for performing study: The motion of the atlantooccipital, cervical vertebral and cervicothoracic joints play an important role in equestrian sports and they are also common sites for lesions limiting performance in horses. Objectives: To calculate inverse kinematics based on cervical vertebral motion and to develop a model close to the measured neck movements. Materials and methods: Measurements were recorded in 6 horses without neck pain. Reflective markers were placed on both cristae facialis, both sides of cervical vertebra 1, 3 and 6 on the withers and hooves. The neck model was reconstructed from CT scans of the osseus structures and was developed in SIMM (Software for Interactive Musculoskeletal Modelling). Inverse kinematics calculation was done in OpenSim. Three degrees of freedom: Flexion-extension (FE), axial rotation (AR) and lateral bending (LB) were considered. 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 analysed using paired sample t tests. Results: From the model, the smallest FE ROM was in the C5-C6 joint (2°Ϯ 1°) and the largest was in the C3-C4 joint (11°Ϯ 5°). The smallest AR ROM was in the C5-C6 joint (2°Ϯ 1°) and largest AR ROM was in the atlantoaxial joint (7°Ϯ 2°). The smallest LB ROM was in the C5-C6 joint (2°Ϯ 1°) and the largest LB ROM was in the cervicothoracic joint (18°Ϯ 5°). There were significant differences between the ROM of joints in 51 of 168 comparisons (P<0.05). Conclusions:The result of the motion of each joint gives an insight into the biomechanics of the equine neck. The small FE ROM at C5-C6 illustrates the pathogenetical relevance of the model for the development of osteoarthritis. The calculated data also provides a source for inverse dynamics.evj_265 516..522

Synovial folds in equine articular process joints

“…The lateral range of motion also increases through the cervical articular process joints, when measured ex vivo . Contrary to the findings ex vivo , the in vivo lateral range of motion and the range of motion by flexion and extension are at their maximum in the cervical joint at C4/C5 in the walk . This is consistent with the findings by Claridge et al .…”

“…In horses, synovial folds in the cervical articular process joints were observed by us in a previous study on another topic , but no systematic studies have been performed on synovial folds in horses. Horses are prone to cervical trauma, just like man, and due to the extensive range of motion in some of the joints and the load upon the cervical articular process joints , synovial folds could become entrapped or disrupted. Furthermore, the synovial folds should be recognised as a compartment within the joint to be avoided when injecting into the joint, provided that they are ubiquitously present in horses.…”

Biochemical and biomechanical characterisation of equine cervical facet joint cartilage

“…The largest angular changes occur in the upper and lower cervical regions, while the mid‐cervical segments move to a lesser degree . Compressive forces are higher on the cranial aspect of the joint during extension and more on the caudal aspect of the joint during flexion , and joint moments created during flexion and extension are greatest in the caudal spinal segments . Thus, it is somewhat surprising that properties of facet joint cartilage were not found to vary across spinal levels or between surfaces, given the variation in mobility across the cervical spine.…”

Horses, saddles and riders: Applying the science

“…An alternative method that uses inverse kinematics to overcome the drawbacks of the use of skin markers for spinal kinematic analysis in horses was described (Zsoldos et al . ). Professor Peham also talked about the development of spinal models based on research data and the future role of motion analysis as a diagnostic aid in horses with back problems.…”

“…Some of the kinematic studies of the horse's back have been based on bone-fixed markers to avoid errors that arise when the skin slides over the underlying bones (Faber et al 2001). An alternative method that uses inverse kinematics to overcome the drawbacks of the use of skin markers for spinal kinematic analysis in horses was described (Zsoldos et al 2010a). Professor Peham also talked about the development of spinal models based on research data and the future role of motion analysis as a diagnostic aid in horses with back problems.…”