2 Answers

There are two types of muscle atrophy.

• Disuse atrophy occurs from a lack of physical activity. In most people, muscle atrophy is caused by not using the muscles enough. People with seated jobs, medical conditions that limit their movement, or decreased activity levels can lose muscle tone and develop atrophy. This type of atrophy can be reversed with exercise and better nutrition. Bedridden people can have significant muscle wasting. Astronauts who are away from the Earth's gravity can develop decreased muscle tone after just a few days of weightlessness.


• The most severe type of muscle atrophy is neurogenic atrophy. It occurs when there is an injury to, or disease of, a nerve that connects to the muscle. This type of muscle atrophy tends to occur more suddenly than disuse atrophy.

Some muscle atrophy occurs normally with aging. Other causes may include:

• Alcohol-associated myopathy


• Amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease)


• Burns


• Dermatomyositis and polymyositis


• Guillain-Barre syndrome


• Injury


• Long-term corticosteroid therapy


• Malnutrition


• Motor neuropathy (such as diabetic neuropathy)


• Muscular dystrophy


• Not moving (immobilization)


• Osteoarthritis


• Polio


• Rheumatoid arthritis  


• Spinal cord injury


• Stroke


• Read more here>>http://www.nytimes.com/health/guides/symptoms/muscle-atrophy/overview.html?inline=nyt-classifier

Missing the "o" when typed.