Changes in navicular bone (os sesamoideum distale) shape in horses as a result of pathological alterations.

This research study effectively investigated if the shape of a horse’s navicular bone (also known as the os sesamoideum distale) changes due to any pathological alterations. The findings showed that altered navicular bones are typically thicker and have higher surfaces for the flexor and middle phalanx joint.

Research Objective and Methodology

• The primary objective of the study was to compare and analyze the shape difference between normal navicular bones and those with pathological changes. The secondary goal was to contrast the metric features of the navicular bone across different horse breeds and relate these features to the size of the middle and distal phalanges.
• The study involved 53 horses from different breeds, further divided into three categories. A thorough anatomical exam revealed that 30 navicular bones were normal, while 23 presented pathological changes.
• The researchers applied various methods of statistical analysis, including the Levene’s test, one-way ANOVA, T-test, LSD test, and Pearson correlation. For this purpose, the shape of the navicular bone was described using seven newly developed indices.

Research Findings and Conclusion

• The results showed that three out of seven indices had statistically higher values in the affected bones than the healthy ones. This indicates that navicular bones with defects are relatively thicker and possess a higher flexor surface and a higher articular surface for the joint with the middle phalanx.
• One of the critical conclusions of the study was that an increase in the thickness and height of the navicular bone is a primary indication of future pathological changes. The adverse changes seem to have occurred in the following stages of the process.
• The research also exposed a strong correlation between the breadth of the middle and distal phalanx, and the breadth and thickness of the navicular bone. Moreover, the study discovered a strong correlation between the height of the flexor surface of the navicular bone and the breadth of the phalanges.