A nerve block is a procedure where the veterinarian injects anesthetic around a nerve to desensitize the area it feeds. Dean Hendrickson, DVM, MS, Dipl. ACVS, professor of equine surgery at Colorado State University, in Fort Collins, explains how this can help vets identify where a horse’s lameness originates by eliminating the pain at a certain point. Knowing the anatomy of the structures around a nerve block is crucial to using this diagnostic tool correctly.