Multivariable Logistic Regression Models of X-Ray Thoracic Spinous Process Osseous Changes Findings and Body Measurement Factors Associated With Defined Over-riding of the Dorsal Spinous in Riding Horses

Thoracic spinous process osseous changes in horses occur due to riding-induced back compression. This study aimed to evaluate the relationship between the findings of thoracic spinous process osseous changes on radiographic imaging and conformation based on the difference in over-riding of the dorsal spinous processes in racing horses. This study included 55 sports horses. The hardness of the back muscles (the multifidus, longissimi, and latissimi collectively) was measured, and the horses were divided into two groups: low muscle hardness (n = 16) and high muscle hardness (n = 39). We confirmed the effectiveness of a muscle hardness tester in measuring the hardness of the back muscles. It was revealed that horses with a long length from the saddle (13th thoracic vertebra) to the sacral lumbar joint (fifth lumbar vertebra) had higher muscle hardness. Additionally, horses with high muscle hardness demonstrated spinous process osteosclerosis. (c) 2021 Elsevier Inc. All rights reserved.