Inflammation of muscular tissue, often associated with pain and swelling, and possible muscular cramp. Myositis can be caused by bacteria, viruses or fungi, but is usually the result of irritation of or damage to muscular tissue through intensive or abnormal use, or cold, as in lumbago and stiff neck. Car drivers and passengers often attract neural and muscular inflammation by travelling with an arm out of the window. Calcification sometimes occurs in the inflamed area, when the condition is known as myositis ossificans, and can result from damage of or irritation to the muscles and adjacent osseous membrane. This form of myositis occurs among other places in the thigh muscles of horse riders. If a number of muscles are inflamed spontaneously the condition is known as polymyositis, in which case inflammation is caused by antibodies against the body’s own cells and proteins, and is associated with muscular tissue decay. The skin is affected as well and so the condition is known as dermatomyositis. Treatment of myositis is by rest and warmth; when discomfort ceases, the muscle must be made flexible again by exercise. Bacterial infection should be treated with antibiotics, polymyositis with corticosteroids.