In medical terms, "MS" stands for "multiple sclerosis." Multiple sclerosis is a chronic disease of the central nervous system, which includes the brain, spinal cord, and optic nerves. It is thought to be an autoimmune disorder, where the bodys immune system attacks the protective covering of nerve cells, leading to communication problems between the brain and the rest of the body. The symptoms of MS can vary widely between patients and may include loss of vision, loss of power in an arm or leg, sensory disturbances, fatigue, depression, incontinence issues, sexual dysfunction, and walking difficulties.