Any horse with an abnormal gait is referred to as “lame.” Lameness indicates that the horse has either a structural or functional disorder of the musculoskeletal system (the limbs or spinal column) that can be appreciated not only while the horse is moving but also standing. A number of underlying causes can result in lameness including trauma, a congenital condition an acquired abnormality and infection.

Even factors unrelated to the musculoskeletal system such as metabolic, circulatory, and nervous system abnormalities can cause a horse to become lame. Because lameness due to musculoskeletal abnormalities is the leading cause of poor performance in athletic horses, being able to diagnose and treat a lame horse is a common and important technique in veterinary medicine.