Displacement Of Center Of Mass In Dogs In Response To Foot Sensory Stimulation

Objective Evaluate center of mass (CoM) displacement values during four-limb and three-limb standing with limb suspension in dogs before and after applying sensory stimulation to a forelimb or hindlimb.Study Design Experimental study.Animals Six clinically normal beagles.Methods A four force-plate apparatus was built to assess static weight distribution. Dogs stood on the device with one limb in contact with each force plate. We created a plastic device to induce sensory stimulation so that lameness could not be detected visually when stimulating the paw. Experimenters confirmed the degree of lameness by walking before and after measurement. Body-weight shifts were induced via suspension of each limb and transient sensory stimulation to the right forelimb or left hindlimb. CoMs of five postures were compared, with and without transient sensory stimulation.Results The four-limb CoM was located cranial to the center of the X- and Y-axis coordinates (X: -0.82 +/- 9.12, Y: 61.00 +/- 5.82). During three-limb standing with suspension of either forelimb, CoM shifted backward toward the contralateral side compared to four-limb standing. During hindlimb suspension, CoM shifted to the contralateral side. With right forelimb sensory stimulation, there were large CoM changes for both four-limb and three-limb standing (X: -34.53 +/- 9.09, Y: 52.21 +/- 6.88). CoM changes were small with left hindlimb sensory stimulation (X: 6.47 +/- 13.86, Y: 69.41 +/- 5.55).Conclusion CoMs during four-limb and three-limb standing were influenced by sensory stimulation of a forelimb and, to a lesser extent, of a hindlimb.Clinical Significance Static evaluation of CoM may aid clinicians in the diagnosis and recovery of forelimb lameness.