Quantification of skin displacement near the carpal, tarsal and fetlock joints of the walking horse

A technique enabling simultaneous visualisation of skin and underlying bony structures in the walking horse was used to quantify skin displacements on the lateral surface of carpal, tarsal and fetlock joints. The technique employed implanted light-emitting-diodes (LEDs) for marking the bone, and self adhesive spot labels for marking the overlying skin. Photographic recordings were made. Skin displacement was measured in six Dutch Warmblood horses. Mean total displacements and mean displacement per degree of change of joint angle were calculated. Displacements at the level of the fetlock joints appeared to be generally small (less than or equal to 2 mm), but displacements up to 2 cm were measured in the distal tibia. Displacements of this magnitude are of importance for the interpretation of results obtained by modern gait analysis techniques.