Evaluation of displacement of the digital cushion in response to vertical loading in equine forelimbs.

The study aims to investigate the patterns of displacement in the digital cushion (a structure found in the foot of a horse) upon vertical loading of the lower forelimb of the horse.

Methodology

• In this research, forelimbs from 10 horses with normal feet were examined.
• The study conducted in vitro vertical limb loading to induce displacement patterns in the digital cushion (DC).
• The DC’s load-induced displacement was measured both in terms of magnitude and direction, using six radio-dense markers percutaneously implanted in specific regions of the DC.
• The study also compared the effects of solar (bottom surface of the horse’s hoof) support and non-support on the displacement of the DC.

Results

• It was observed that regional displacement of the DC predominantly occurred along the distal (remote from the point of attachment) and palmar (pertaining to the back of the horse’s foot, in veterinary terms) vectors when vertically loaded.
• The study found variable medial (towards the midline) or lateral abaxial (outer side) displacements, seemingly contingent on the limb’s response to the applied load.
• The displacement of the DC was not influenced by the degree of solar support.

Conclusions

• The findings suggest that the biomechanical role of the digital cushion is to act as a restraint to the displacement of the second phalanx (bone in the horse’s foot) or function as a passive structure permitting flexibility of the rear two-thirds of the foot.
• The study did not show evidence that the digital cushion creates a force inducing displacement or a proactive restraint against outward displacement of the hoof wall capsule.