This article consists of a description of the flexor and extensor tendons and suspensory ligament. Included are images with labels of the major muscles, their associated tendons, and underlying ligaments of the lower legs of horses.

Flexor and Extensor Tendons

Tendons attach muscle to bone. When the muscle contracts force is applied to the bone through the tendon. This force can result in either static action, as in the standing horse, or result in motion. When standing, the balance of the pull of the extensor and flexor tendons predominate. The forward motion of the legs is created with the extensors contracting. The rearward (propulsive) motion of the legs is created by contraction of the flexors.

Tendons are made of carefully arranged protein fibers, primarily collagen, that are elastic. As long as the elastic tendon is not over stretched it recovers to it's original length without damage. Too much force and the tendon is over-stretched and damaged or even may tear. This describes an acute tendonopathy that is accompanied by inflammation and we label it tendonitis.

Tendons travel within the connective tissue matrix of the body. At places of high motion and friction, the tendon may travel within a synovial sheath. This sheath secretes and sequesters a lubricating fluid called synovial fluid, similar to that found in joints. It is important to understand this relationship and to know where the sheaths are. By knowing the sheaths locations, you can better understand the swelling you might see, what type disease process is going on, the best treatment plan, and the possible complications. It is possible to have the sheath alone inflammed: synovitis or both the tendon and sheath inflammed: tenosynovitis.

Ligaments

Ligaments are much like tendons, composed primarily of an elastic collagen, but have a different function. They attach bone to bone creating a joint. Most joints have considerable range of motion with the ligaments acting as hinges. Some joints are relatively fixed in place by their ligaments, for instance the pastern joint. Like tendons they can suffer from overstretching or trauma. Disease of the ligaments is called desmopathy and the accompaning inflammation desmitis.