The effect of diagnostic regional nerve blocks in the fore limb on the locomotion of clinically sound horses.

The practice of applying diagnostic nerve blocks relies on the assumption that the blocks in themselves do not alter the horse's gait. This assumption has recently been challenged. In the present paper a series of sequential nerve blocks (low palmar digital block, abaxial sesamoid block, high palmar block) was applied to clinically sound horses. Before and after each block the gait was clinically scored and Ground Reaction Forces (GRF) were measured. Clinical scoring did not change after any of the nerve blocks. None of the GRF variables changed significantly except for a slight alteration of the time at which the longitudinal GRF changed from a decelerative to a propulsive force. It is concluded that the basic assumption that diagnostic nerve blocks do not essentially alter the gait of a sound horse is correct.