If your horse is lame, or its joints are inflamed and swollen, it may be suffering from some stage of degenerative joint disease. The following illustration demonstrates the operation of a normal horse joint. The synovial membrane surrounds the joint and functions to produce synovial fluid.
Synovial fluid fills the joint cavity completely.
It acts as a means of transportation of the nutritive substances required by the cartilage and lubricates the soft tissues of the joint to prevent inflammation and pain. Joint disease often starts with inflammation of the tissue which surrounds the joint, called the synovial membrane. The inflamed membrane begins leaking fluid, blood cells and enzymes into the joint, which ignites a process that results in an ongoing cycle of joint destruction. The enzymes, which have been introduced into the joint, break down the thick, lubricating synovial fluid into a non-lubricating watery liquid, resulting in increased pain, reduced cartilage nutrition and an attack on the vital joint cartilage. As the cartilage break down begins, and expands, it fuels the degenerative process and continues the disease cycle.