Tendon injuries can be extremely frustrating. The best way to deal with them is to make every effort to prevent them, or if possible, limit the degree of damage that occurs. Certainly some tendon injuries occur acutely without any warning, but many more severe injuries are preceded by some signs of subtle lameness or palpable abnormalities in the tendons. It is therefore important to learn something about tendon structure and function and to perform a basic examination of the tendons in an effort to not exercise a horse with a potential or developing tendon problem.

Anatomy and Function

The structure as well as the function of a horse’s lower limb is beautiful, amazing, somewhat perplexing, and down right complicated. The first thing to understand is the difference between a tendon and a ligament. A tendon is defined as “a fibrous cord of connective tissue continuous with the fibers of a muscle and attaching the muscle to bone or cartilage”–a muscle to bone connection. A ligament is defined as “a band of tissue connecting bone or cartilage, serving to support and strengthen joints”–a bone to bone connection. Tendons and ligaments are made up of the densest form of fibrous connective tissue, consisting of parallel bundles of coarse collagen fibers; collagen is a protein substance that makes up many of the body’s connective tissues, including skin and subcutaneous tissue as well as tendons. The simplified difference between the collagen

in the elastic tissue of the skin and that in a tendon is the degree of organization of the collagen fibers. In the skin, the collagen fibers are loosely arranged and do not have much “strength,” whereas in the tendon, the collagen fibers are of a special type and very tightly organized in a parallel nature, providing a significant increase in strength.

Tendons have great tensile strength. Tensile strength refers to the resistan