Quantification of Equine Sacral and Iliac Motion During Application of Manual Forces and Comparison Between Motion Capture With Skin-Mounted and Bone-Fixated Sensors.

The research paper studies the motion of two major horse bones, the ilium and sacrum, under the application of manual forces and compares the measurements recorded by sensors mounted on the skin and those attached to the bones.

Objective of the Research

• The main purpose of this study is to quantify the amount and direction of motion of the ilium and sacrum in horses during the application of manual force. Additionally, the research aims to compare the measurements obtained from two types of motion sensors – those attached to the skin and those fixed to the bones.

Research Methodology

• Six Thoroughbred horses were selected for this experiment. Sensors were first attached to the skin over two specific points on their skeletal structure – the tuber sacrale (TS) and the third sacral spinous process.
• Subsequently, the sensors were fixed to the same bony landmarks using Steinmann pins.
• An investigator recorded the changes in the orientations of each TS and sacrum during six trials of applying manual force to the horse’s pelvis that caused movements in cranial, caudal, and oblique directions.
• Mean values of these changes were calculated in terms of Euler angles for three orthogonal planes: lateral bending, flexion-extension (FE), and axial rotation (AR).
• A statistical analysis was carried out to determine the differences between findings from skin-and bone-fixated markers with the significance set at P< 0.05.

Findings and Conclusion

• The highest mean values during pelvic rotations were reported for the flexion-extension movement (2.08° ± 0.35°) with bone-fixated sensors and the axial rotation motion (1.70° ± 0.48°) with skin-mounted sensors.
• The study found a weak correlation between measurements from skin-mounted and bone-fixated markers. This was especially evident in the axial rotation plane, where results from skin-mounted sensors were closest to those from bone-fixated sensors.
• However, the study concludes that skin-mounted sensors cannot predict bony kinematics during the application of external force to the horse’s pelvic region accurately, due to discrepancies in the measurements from skin and bone-mounted sensors.