Localization of the cutaneus trunci muscle reflex in horses.

The researchers of this study investigated how horses’ skin moves in response to localized stimulation on certain areas of their body. The results could have implications for understanding horses’ responses to the placement of tack or other equipment on their skin.

Objective and Methodology of the Study

This study aims to determine the magnitude and location of skin movement in horses, caused by the cutaneus trunci muscle reflex, following localized stimulation on the dorsolateral aspect of the thoracic wall.

• In this study, eight horses were used as the subjects.
• A total of fifty-six reflective markers were applied to the lateral aspect of the body wall of each horse. They were arranged in a grid pattern at ten-centimetre intervals in seven rows and eight columns.
• To stimulate the skin on the dorsolateral aspect of the thoracic wall at the levels of T6, T11, and T16, tactile stimulation was performed.
• A motion analysis system, equipped with ten infrared cameras, was used to track the motion of the reflective markers following the tactile stimulation.
• The movement data of the markers were then used to create a skin deformation gradient tensor field. This data dispersion was analyzed using custom software.

Results of the Study

The study found that the areas of greatest skin deformation were located close to the stimulation sites. These twitch response centres were located at an average distance of 7.7 to 12.8 cm ventral, and between 6.6 cm cranial and 3.1 cm caudal to the stimulation sites.

Implications and Conclusions

The results of this study could be useful for determining the conduction velocities of the cutaneus trunci muscle reflex in horses. This information could enhance understanding of horses’ reactions to the application of tack or other equipment on the skin overlying the cutaneus trunci muscles. A better understanding of these reflexes and responses can assist horse trainers and owners in determining the most appropriate and comfortable placement of such equipment. This could potentially lead to improved horse welfare and performance.