Many athletic horses suffer tendon and ligament injuries, which can end a competitive life not handled quickly.

Tendons and ligaments are similar in structure, but, generally speaking, tendons are more flexible and stretch more. Both are made up of collagen, a tough protein substance found in skin, tendons, bone, cartilage, ligaments, and all other connective tissues. Collagen allows tendons and ligaments to stretch and contract and also gives them their toughness.

Part nine of the anatomy and physiology series concentrates on the tendons and ligaments in the limbs of the horse, especially the forelimbs, which often are the sites of injury and disease. This article examines the construction of tendons and ligaments, how they function, and what can happen when something goes awry.