Objective—To evaluate patterns of digital cushion
(DC) displacement that occur in response to vertical
loading of the distal portion of the forelimb in horses.
Sample Population—Forelimbs from 10 horses with
Procedure—Patterns of DC displacement induced by
in vitro vertical limb loading were determined. Loadinduced
displacement of the DC was defined as the
magnitude and direction of displacement of 6 radiodense,
percutaneously implanted markers in specific
regions of the DC. The effects of solar support and
nonsupport on displacement of the DC were compared.
Results—Regional displacement of the DC occurred
principally along distal and palmar vectors in response
to vertical loading. Medial or lateral abaxial displacements
were variable and appeared to be dependent
on response of the limb to the applied load.
Displacement of the DC was not affected by the
degree of solar support.
Conclusions and Clinical Relevance—Data indicated
that the biomechanical function of the DC is to act
as a restraint to the displacement of the second phalanx
or as a passive structure that allows flexibility of
the caudal two thirds of the foot. Results did not indicate
that the DC provides a force that induces displacement
of or an active restraint against outward
displacement of the hoof wall capsule. (Am J Vet Res 2005;66:623–629)