Glossary
Movement asymmetry.
Direct answer
Movement asymmetry is the measurable difference between the left and right sides in the vertical displacement of head, withers and pelvis across one stride cycle, recorded with inertial sensors or optical motion capture. Movement asymmetry describes how a horse moves and says nothing on its own about pain.
The commonest misreading is to equate asymmetry with lameness. Among horses considered sound by their owners, a substantial proportion exceeds the usual thresholds. Asymmetry is a measurement result and only acquires meaning alongside clinical examination and imaging, never in isolation from the animal itself.
Compensation adds a further layer. A hindlimb problem can produce a head movement that looks like a forelimb problem, and the reverse also happens. Circle, speed and surface shift the values systematically. In people, gait analysis is largely interpreted limb by limb; in the quadruped horse all four limbs are linked within the calculation.
LamenessDynamic examinationDiagnostic analgesia (nerve block)Spinal kinematics
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