Equine upper limb kinematics: Comparison between biplanar high-speed fluoroscopic kinematography and optoelectronic motion capture in one Mini Shetland Pony.

BACKGROUND

There are no studies describing the kinematics of the proximal limb skeleton in living equids. In horses like in all other therian mammals studied so far, the scapula rotates around an instantaneous center of rotation rather than a fixed pivot point, which increases the susceptibility of skin marker-based methods to inaccuracies.

AIMS/

OBJECTIVES

The aim of the study was to describe the skeletal movement of the proximal equine limb and to overcome limitations traditionally associated with skin marker displacement errors.

METHODS

Optoelectronic motion capture (OMC) and biplanar high-speed fluoroscopic kinematography (FluoKin) of the proximal limbs have been performed simultaneously in one pony walking and trotting on a treadmill. Data analysis followed scientific rotoscoping.

RESULTS

In FluoKin, the mean range of motion (ROM) of the scapula was 27.6° (± 0.9, n = 2) during walking and 23.3° (± 3.7, n = 9) during trotting. The mean ROM of the hip joint was 29.5° (± 2.3, n = 3) during walking and 33.2° (± 3.8, n = 7) during trotting. In comparison to OMC, the ROM derived from FluoKin data always showed higher values. This was most pronounced in the elbow joint and stifle with a deviation between both systems of up to 33.0 and 28.1°, respectively.

CONCLUSION

First insights into the detailed skeletal movements of a pony's proximal limb during walking and trotting have been obtained.