The musculoskeletal system of the horse is anatomically shaped for various structures of the musculoskeletal system. The bones, joints, muscles, tendons and ligaments interact harmoniously during locomotion.
Both soft tissue and bone tissue are designed to withstand forces of varying intensity repeatedly without undergoing changes in structure and function. However, each tissue has a certain resilience that depends on its composition, anatomical location and function. The tissues of the musculoskeletal system maintain a constant physiological balance. To break this balance, the resilience of a tissue is overcome by excessive physical demand, which induces the decline of tissue function and the presentation of damage to tissue structure which translates as an injury.

Inflammation and pain are the main clinical signs that occur when there is tissue injury, whether of a joint, ligament, tendon or muscle. Lameness or claudication is the most obvious clinical manifestation of pain in a limb, either by the compression effect of nerve endings during an inflammatory process or by direct trauma to the tissues.
The lameness in horses are classified into 4 types: support, elevation, and mechanical joint. The first is related to bone and joint injuries and the second most commonly occur in cases of tendon and ligament.
Moreover, there are 5 different degrees of lameness. Grade 1 is the lightest and is often undetectable in any of the 3 air movement (walk, trot and canter), while grade 5 is characterized by a lack of support from the member on the floor. Grades 2, 3 and 4 are increasing according to the degree of pain that presents the horse.

Pending of translation