This chapter describes the lesions which most commonly affect the joints, tendons and muscles, prescribing the appropriate therapeutic treatment. The origin of the painful lesion can be either traumatic or rheumatic. Radiography reveals modification of the joint margins of the subchondral part of the bone, and of the periarticular soft tissues within the cartilaginous space. The circulation of blood through the tendon is precarious. In the Horse, the main vessels enter via the paratenon, branching longitudinally and transversally within the epitenon, and supply a very delicate network within the endotenon. Tendinopathies frequently affect the athletic horse. Their characteristics and incidence vary according to the level of activity and discipline in which the horse specializes. Initially, swelling can be moderate and may be underestimated, as the horse is not necessarily lame. In order to check the functional integrity of the tendons, the metacarpophalangeal, proximal interphalangeal and carpal joints should be examined.