F. Audigie et al., ASYMMETRY IN PLACEMENT OF BILATERAL SKIN MARKERS ON HORSES AND EFFECTS OF ASYMMETRIC SKIN MARKER PLACEMENT ON KINEMATIC VARIABLES, American journal of veterinary research, 59(8), 1998, pp. 938-944
Objective-To evaluate asymmetry in placement of bilateral skin markers
on horses and to determine effect of asymmetric skin marker placement
on kinematic variables for trotting horses. Animals-10 horses for eva
luation of asymmetry in marker placement; 1 horse for evaluation of ef
fects on kinematic variables. Procedure-Asymmetry in marker placement
was assessed by attaching markers to horses and comparing radiographs
of left and right limbs. An experimental model was developed to determ
ine effects on kinematic variables; accuracy of the model was validate
d experimentally. Using kinematic data from a clinically normal trotti
ng horse as reference data, effects of asymmetric marker placement on
vertical displacement-time and joint angle-time diagrams were determin
ed by use of the model. Results-Asymmetry of placement was < 1 cm for
markers on the distal portions of the limbs and < 2 cm for markers on
the proximal portions. Asymmetric marker placement did not alter gener
al shapes of the vertical displacement-time and joint angle-time curve
s. In most instances, largest differences in vertical displacement att
ributable to asymmetric marker placement were equal to or less than ma
gnitude of the asymmetry of placement. Alterations in joint angle-time
curves were mainly a result of shifting of the curves on the Y axis.
Joint range of motion was only slightly changed by asymmetric marker p
lacement, but maximum flexion and extension angles were greatly altere
d. Conclusions and Clinical Relevance-Some kinematic variables can be
greatly altered by small differences in skin marker placement. Such ef
fects should be taken into account when evaluating kinematic data for
sound and lame horses.