Kinematics of the equine distal sesamoid (navicular) bone of the thoracic limb.

The research investigates the movement and rotation of a specific bone (distal sesameoid bone, DSB) in horse limbs using CT scans and medical software. Differences in movement and rotation were identified between whole limbs and partial limbs, indicating that the cutting of flexor tendons impacts these aspects.

Research Process

• The study involved the collection of 30 horse limbs from cadavers, consisting of partial (12), full (8), and matched full and subsequently cut limbs (10).
• Volume CT images were taken of these limbs in three positions: full extension, neutral, and maximally flexed.
• The average translation and rotation of the DSB within each limb were then calculated.
• The researchers used two-way ANOVA and post hoc Tukey’s tests to analyze the differences, with a significance level set at P < 0.05.

Main Findings

• Dorsal translation was found to be significant during extension, for both complete and partial limbs.
• Distal translation was significant during extension and flexion in both full and partial limbs.
• A significant rotation about the mediolateral axis was observed during extension and flexion.
• The movement and rotation of the DSB varied significantly between full and partial limbs.

Conclusions and Recommendations

• This study presents the first quantifiable measure of DSB’s movement and rotation within the hoof of a horse.
• The finding that partial limbs showed significantly less movement when compared to full limbs suggests that the cutting of flexor tendons modifies the movement of the lower thoracic limb.
• The authors recommend additional investigations to determine if diseases in the ‘podotrochlear apparatus’ (the region of the hoof containing the DSB and relevant ligaments) influence clinical lameness results.