Asymmetry of the forelimbs of the horse is acknowledged as a common condition1, which can result in asymmetric movement, abnormities of gait and even lameness2. Limb length disparity (LLD) has been previously classified into two categories: structural and functional3.
Structural LLD refers to an asymmetry in bone length when compared between a pair of limbs, while functional LLD refers to an asymmetry in the muscular buildup and the angles that joints form with each other when compared between a pair of limbs. The causes of this condition include flexural limb deformity, uneven bone growth due to injury, pectoral paralysis4, grazing stance5 and lameness6. This is often coupled with the appearance of mismatched feet (Figure 1).
A recent study by Hall7 found no significant difference in third metacarpal measurements of length, width and circumference in 15 pairs of cadaver limbs.
In 2014, I published my investigation on the existence of static and dynamic asymmetry in 10 unbroken horses8. The study found a significant difference in stride length and stride velocity at the trot between a pair of forelimbs. The symmetry indexes of the hoof surface area and the dynamic flight increased following farriery intervention of trimming to a standardized trimming protocol.
Until now, most of the studies of LLD have provided anecdotal evidence with no clear quantifiable method of assessment for the condition. To the researcher’s knowledge, no study has been performed for assessment of the visible…