November is Arthritis and Joint Health awareness month. This month we are talking more about arthritis prevention, control and treatment is dogs and cats.
Arthritis is a term used to describe swelling or inflammation in any joint. A joint is that place where 2 bones move against each other. Dogs and cats have more than 140 joints in their bodies. We commonly think of hip, knee and elbow joints. There are joints between each vertebra in the back, 2 joints that allow the jaw to open, 2 joints in each ear that assist with hearing. So, as well as the commonly thought of joints in the legs, there are many others that can be affected by arthritis.
When bones meet and rub against each other, the reason it does not hurt or sound awful is due to the cartilage that lines the ends of the bones and a thick lubricant (synovial fluid) between the cartilage. When the cartilages are healthy and the synovial fluid is thick, the bones in the joint glide effortlessly over each other with ease.
The cartilage in joints is composed of an outer slippery layer and an inner spongy layer. The spongy layer holds water and acts as a cushion. The outer layer has no blood supply to it. The synovial fluid is very slippery and it helps make the outer layer of the cartilage more slippery. The synovial fluid also supplies nutrients to the outer layer of cartilage. When a joint moves it pumps synovial fluid around inside it which feeds the cartilage, keeping it healthy and slippery which promotes the effortless gliding of the joint.
When arthritis affects a joint it first changes the synovial fluid. The fluid becomes thinner and less lubricating and it starts to hold inflammatory substances that instead of feeding the cartilage actually start to destroy it. This eventually leads to death and wearing away of the cartilage which makes the bending of the joint harder and painful. Our pets bodies are for the most part self healing so, if there is a tear or wearing away of the cartilage the body tries to produce more to replace the damaged bits. The replacement cartilage is never as good as the original.
