Types of Joints In Horses

Types of Joints In Horses

Knowing types of joints in horses and how they work is vital for soundness and performance. Joints make up functional units of the horse’s musculoskeletal system. Not only do joints function as independent units for movement, but they also provide points of unity throughout the body. Here, we explore the different types of joint in horses and their importance.

Types of joint in the horse can be split into three categories;

  • Synovial
  • Fibrous
  • Cartilaginous

These three joint types all play a key role in function, joining over 200 bones in the horse’s body. All the types of joints in horses comprise of highly specialised tissues to ensure perfect function, performance, and comfort when working optimally.

Synovial Joints

Synovial joint are key structures for movement within the horse’s body. Synovial joints are made up of multiple structures and features to aid smooth movement, shock absorption, as comfort throughout movement.

Synovial joint comprise of the end of two bones and where they join is the ‘joint’. To keep movement as fluid as possible, where bone meets is covered in smooth but resilient material, called articular cartilage.

Surrounding the joining site of the two bones is fluid filled membrane. The membrane, called the synovial membrane, holds and stores nutrient-rich and lubrication fluid. The fluid, known as synovial fluid, ensure comfort through movement and health of the joint is maintained throughout life. This fluid is filled with naturally occurring nutrients such as hyaluronic acid and hyaluronate. Ingredients such as hyaluronic acid and Glucosamine HCL can be key for synovial fluid maintenance. Topping up levels of these naturally occurring compounds can help maintain joint health, especially though period of hard or increasing workload.

Further encircling the synovial membrane, there is a structure called the joint capsule. This is a fibrous structure aiding stability and ensuring the joint stays intact during high-force activities such as jumping.

Aiding with the movement of joints, many muscles contract and relax. Tendons are the insertion points of muscle into bone and undergo high strain which is why they can be prone to injury. Meanwhile ligaments play a supporting role in joint integrity, attaching bone to bone.

Examples of synovial joints include;

  • The fetlock joint
  • The carpal (knee) joint
  • The hock joint

 

Fibrous Joints

There are less fibrous joints within the horses’ body and they usually do not cause problems with performance or comfort. However, within growth or development they may be more troublesome.

Fibrosus joints are connected by dense connective tissue, mainly consisting of collagen. They do connect bones but are fixed and immovable. Having no movement, fibrous joints do not have the structures of a synovial joint. However, this do not mean we don’t have to prioritise their health.

Found between skulls bones and binding teeth to their socket, looking after fibrous joints is very important for overall health and development.

During development, skull bones are unfused so that they can compress the size of the skull during birth. After birth, these unfused skull bones gradually begin to fuse and become immoveable to protect the brain. Therefore, appropriate nutrition for young horses, containing adequate collagen, protein and vitamins is essential to support the skulls’ protective function.

With fibrous joint also binding teeth to their socket, these joints are vital for overall dental health. It is well known that joints adapt to the loads exerted on them. Therefore, adequate loading through provision of fibre can help to maintain dental health and encourage adaptation of the joints to large chewing loads. In future, this could help prevent tooth loss but also increased forage can reduce appearance of sharp points on the teeth.

Types of Joints in Horses

Cartilaginous

Cartilaginous joints are joint which are connect by cartilage material, usually fibrocartilage or hyaline cartilage. Cartilaginous joints allow for more movement between joint than fibrous joints but are less mobile than synovial joints.

Cartilaginous joints in the horse include those between the vertebrae of spine. There are important to help absorb impact and provide a small degree of movement for efficiency of the other limbs.

They can also be found through the horse’s body as they are developing, known as growth plates. Growth plates are founded between the rounded end of long bones (such as the cannon bone) and mid-section of long bones. The cartilaginous joint help the bone to grow in length and width and is eventually converted into solid bone. Some studies suggest that supplementing horses diets with yeast can strengthen horses’ growth plates during development.

Health of cartilaginous joints is reliant cells called chondrocytes, producing new collagen and proteoglycans for cartilage. Chondroitin sulphate, Glucosamine HCL and Methylsulfonylmethane (MSM) are key players in maintaining cartilage health. Chrondotin can be especially useful in older horses who may begin to lose a percentage of this essential compound.