Joints & tendons
The tendons and joints in horses are complex anatomical structures that play an important role in the movement and support of the body. Here is a rough overview of the structure of tendons and joints in horses:
Tendons:
Due to their elasticity, tendons have a springy property and serve as elastic force transmitters that transfer muscle force to the bones. They are mainly composed of:
- Collagen fibers: The main component of tendons are collagen fibers. These strong and resilient fibers are arranged in parallel bundles and give the tendons their strength.
- Fascicles: Collagen fibers are grouped into smaller units called fascicles. These fascicles are surrounded by connective tissue that supports the structure and provides protection.
- Tenoblasts and Tenocytes: These cells are responsible for producing and maintaining collagen fibers. Tenoblasts are young cells that produce collagen, while tenocytes are mature cells that maintain and repair the fibers.
Since only around 3% of tendons are connected to the blood supply, their nutrient supply and thus the ability to regenerate is limited and takes a long time. Regeneration can be supported very successfully by administering glycosaminoglycans and collagen peptides.
Joints:
A joint is the movable connection between two or more bones. It allows movement and flexibility in the body. The structure of a joint can vary depending on the type, but here is a general overview of the structure of a synovial joint, which is the most common type of joint:
Articular cartilage: Articular cartilage covers the ends of the bones that form the joint. It consists of a smooth, elastic fabric layer that reduces friction and provides shock absorption. The cartilage is not connected to the blood supply at all (in contrast to the tendon, which is at least minimally supplied with blood); its supply and disposal occurs exclusively via the synovial fluid. Articular cartilage shows changes in its thickness, volume, and elasticity based on movement and loading. This is due to the properties of the synovial fluid and the behavior of the cartilage tissue. During rest phases in which the joint is not heavily loaded or moved, the synovial fluid in the joint space can become more viscous. This is to keep the fluid in the joint and prevent it from leaking out of the joint space. As a result, the articular cartilage can be compressed, causing its volume to decrease (by up to 50%!) and its elasticity to temporarily decrease. This is one of the reasons why joints can appear stiff after long periods of rest.
For this reason, horses should be walked for at least 15 minutes before starting training to ensure the full function of the joint cartilage!
During movement, synovial fluid becomes more fluid to lubricate the joint and provide nutrients to the cartilage. This causes the cartilage to absorb fluid, increasing its volume and increasing its elasticity. This absorption of fluid makes the cartilage more elastic and allows for better shock absorption during movement.
The changes in cartilage during rest and movement are part of its adaptive properties, aimed at ensuring an optimal balance between protection, lubrication and mobility in the joint.
Joint space: Between the ends of bones covered with articular cartilage there is a narrow space called the joint space.
Joint capsule: The joint capsule is a connective tissue shell that surrounds and protects the joint. It consists of two layers: the outer fibrous layer and the inner synovial layer.
Synovial membrane: The inner layer of the joint capsule is called the synovial membrane. It produces synovial fluid, which lubricates the joint and provides nutrients for the articular cartilage.
Synovial fluid: The synovial fluid, also known as synovia, fills the joint space and plays a crucial role in the functioning of joints. She has several important tasks:
Lubrication: Synovial fluid acts as a natural lubricant for the joint surfaces. It reduces the friction between the movable bone ends and thus enables gentle and low-friction movement of the joint.
Shock Absorption: The fluid in the joint space provides some shock absorption by absorbing impact forces during movement. This is particularly important to protect the articular cartilage from excessive pressure and damage.
Nutrient supply: The synovial fluid contains nutrients that are important for the health of the articular cartilage. These nutrients are absorbed from the fluid on the joint surface because the articular cartilage itself is not directly supplied by blood vessels.
Waste disposal: In addition to providing nutrients, the synovial fluid also enables the removal of waste products and metabolic breakdown products from the joint.
Immunity and Protection: Synovial fluid also contains immune cells that help fight off potential harmful microorganisms and regulate inflammatory responses to maintain joint health.
The correct amount and quality of synovial fluid is crucial for the smooth functioning of the joint. Disturbances in the production or composition of the synovium can lead to joint problems such as pain, stiffness and inflammation.
Ligaments: Ligaments are strong, fibrous structures that hold the bones together in a joint. They provide stability and limit movement of the joint. Like tendons, ligaments are also made of collagen fibers, which give them their strength.
In short, the combination of these components allows the joint to move while the articular cartilage protects the joint surfaces and ensures smooth movement. Synovial fluid promotes lubrication and nutrition of the articular cartilage, while ligaments and tendons provide stability and power transmission.
Tendon and joint health is crucial to the horse's mobility and well-being. Therefore, it is important to pay attention to their care and support.
There are various substances that can be used to support tendons and joints in horses. These substances are often offered as supplementary feed and are intended to help improve the health of tendons and joints. Here are some of the most common fabrics:
- Glucosamine: Glucosamine is an amino sugar that occurs naturally in cartilage tissue and plays a central role in the formation of glycosaminoglycans, which in turn are important components of cartilage and synovial fluid. Glycosaminoglycans are large molecules that support the structure and function of articular cartilage. The most important GAGs are hyaluronic acid, keratan sulfate, heparan sulfate, chondroitin sulfate, glucosamine sulfate. It is often used to support cartilage health and can help protect cartilage from wear and tear.
- Chondroitin: is a component of cartilage tissue and is often used together with glucosamine. It can help improve the elasticity and shock absorption of cartilage.
- MSM (Methylsulfonylmethane): MSM is an organic sulfur compound that may have anti-inflammatory properties and is involved in the formation of collagen and keratin. It is often used to support joint health.
- Hyaluronic Acid: Hyaluronic acid is a natural substance found in articular cartilage that helps lubricate joints. Hyaluronic acid supplements can improve synovial fluid and promote mobility.
- Collagen: Collagen is a major component of connective tissue, including tendons and ligaments. Supplementing with collagen can help support the strength and elasticity of these tissues.
- Omega-3 fatty acids: have anti-inflammatory properties and can help relieve joint pain. They can be obtained from sources such as flaxseed oil or fish oil.
- Antioxidants: Antioxidants such as vitamin C and vitamin E can help reduce oxidative damage in tissues, which can contribute to tendon and joint health.
However, before using nutritional supplements for your horse, it is important to seek veterinary advice. A veterinarian can assess your horse's individual needs and make recommendations to ensure optimal support for the tendons and joints.
