Osteoarthritis, sometimes called degenerative joint disease or osteoarthrosis, is the most common form of arthritis. Osteoarthritis occurs when cartilage in your joints wears down over time.

Osteoarthritis can affect any joint in your body, though it most commonly affects joints in your hands, hips, knees and spine. Osteoarthritis typically affects just one joint, though in some cases, such as with finger arthritis, several joints can be affected.

Osteoarthritis treatments can relieve pain and help you remain active. Taking steps to actively manage your osteoarthritis may help you gain control over your osteoarthritis pain.

An autoimmune disorder is a malfunction of the body's immune system that causes the body to attack its own tissues.

Some of the more common autoimmune disorders include rheumatoid arthritis, systemic lupus erythematosus (lupus), and vasculitis, among others. Additional diseases that are believed to be due to autoimmunity include glomerulonephritis, Addison's disease, mixed connective tissue disease, polymyositis, Sjögren's syndrome, progressive systemic sclerosis, and some cases of infertility.

Bone disorders can be caused by injury or cancer, can be inherited, occur as part of a child's growth, or can occur for no known reason. Some bone disorders can cause pain and difficulties walking, whereas others cause no symptoms. Doctors base the diagnosis on a thorough history, close observation and examination, and the selective use of x-rays.

Osteoporosis, osteopenia are one of the common bone disorders not diagnosed at early stages. These may lead to fractures and bone deformities like scoliosis. or kyphosis. With early diagnosis and treatment, these conditions can be prevented.

Musculoskeletal pain can be caused by damage to bones, joints, muscles, tendons, ligaments, bursae, or nerves. Injuries are the most common cause. If no injury has occurred or if pain persists for more than a few days, then another cause is often responsible.

Muscle pain is often less intense than that of bone pain but can be very unpleasant. For example, a muscle spasm or cramp (a sustained painful muscle contraction) in the calf is an intense pain that is commonly called a charleyhorse. Pain can occur when a muscle is affected by an injury, an autoimmune reaction (for example, polymyositis or dermatomyositis), loss of blood flow to the muscle, infection, or fibromylagia.

Soft tissue rheumatism is one of the most common disorders facing the primary care physician. Among the more common types are subacromial bursitis, epicondylitis, trochanteric bursitis, anserine bursitis, and fibromyalgia. The keys to the diagnosis of soft-tissue rheumatism are the history and, more importantly, the physical examination.

Vasculitis is an inflammation of your blood vessels. Also called angiitis, vasculitis causes changes in the walls of your blood vessels, including thickening, weakening, narrowing and scarring. Inflammation can be short-term (acute) or long-term (chronic) and can be so severe that the tissues and organs supplied by the affected vessels don't get enough blood. The shortage of blood can result in organ and tissue damage, even death.

There are many types of vasculitis and, although rare, vasculitis can affect anyone. Some age groups are affected more than others, depending on the type of vasculitis. Some forms of vasculitis improve on their own, but others require treatment — often including taking medications for an extended period of time.

Nerves connect with muscles at the neuromuscular junction. There, the ends of nerve fibers connect to special sites on the muscle's membrane called motor end plates. These plates contain receptors that enable the muscle to respond to acetylcholine, a chemical messenger (neurotransmitter) released by the nerve to transmit a nerve impulse across the neuromuscular junction. After a nerve stimulates a muscle at this junction, an electrical impulse flows through the muscle, causing it to contract.

Disorders in which the neuromuscular junction malfunctions include myasthenia gravis, botulism, and Eaton-Lambert syndrome. In addition, many drugs (including very high doses of some antibiotics), certain insecticides (organophosphates), curare (an extract from plants formerly placed on the tip of some poison darts and used to paralyze and kill), and the nerve gases used in chemical warfare can cause the neuromuscular junction to malfunction. Some of these substances prevent the normal breakdown of acetylcholine after the nerve impulse has been transmitted to the muscle.