Soundness in the horse is dependent on the healthy functioning of all the components of the musculoskeletal system. A horse’s joints need proper alignment and support in order to remain healthy and pain-free. An unstable or poorly aligned joint is subject to inappropriate strain and wear and tear and can contribute to joint inflammation and injury.
Here’s a look at the some of the most important structures that help protect and support a horse’s joints:
LIGAMENTS – Ligaments are strong, fibrous bands of connective tissue that hold bones together at joints. They play a key role in joint stability, providing firm support so that bones do not move out of alignment. A horse’s ligaments will grow thicker and stronger in response to increased levels of exercise and training – an adaptive process that takes place over a period of months.
Ligaments are rich in proprioceptors – a specialized type of sensory receptor that relays information about the position and movement of the body and limbs in space. Chronic inflammation can inhibit the accurate functioning of these receptors, reducing fine co-ordination and predisposing the joint to injury.
MUSCLES – Appropriate muscular development, strength and co-ordination are essential to healthy, fluid movement and effective stabilization of the joints. Like ligaments, equine muscles have an adaptive response to exercise, increasing in strength and size, and improving in oxygen utilization. Muscular restrictions, imbalance and fatigue can all contribute to uneven loading of joints, increasing the wear and tear placed on them. Like ligaments, muscles (and their tendinous attachments) also play an important role in proprioception, a function that can become reduced with muscular fatigue or strain.
CARTILAGE– Articular cartilage is the smooth layer of specialized connective tissue that lines bones where they meet in a joint. Cartilage requires both weight-bearing and movement of the joint to stay healthy. Unlike muscles and ligaments, research suggests that cartilage has little adaptive capacity after a horse reaches the age of two. Additionally, cartilage does not contain blood vessels and therefore is very slow to heal. Inflammation within the joint due to injury, instability or infection, is harmful and can degrade the cartilage.
SYNOIVIAL FLUID – Synovial fluid is the viscous liquid that provides lubrication within a horse’s joint. It is secreted by the inner lining of the joint capsule and helps to protect and nourish the cartilage. With inflammation synovial fluid looses its viscosity becoming more watery and less able to protect the cartilage from wear and tear.
> A number of structures contribute to the healthy functioning of a horse’s joints. When working together properly they help to ensure that the joints operate in a safe and balanced way.