When muscle and bone tissue are not used, they will begin to shrink and waste away, known as atrophy. Atrophy, even minor, in muscle or bone can cause some loss of strength and motion. Some atrophy can normally occur as people age.
There are two types of atrophy in muscles. The most common is disuse atrophy, which occurs when people do not use their muscles enough. It can be reversed by establishing better diet and exercise habits.
Neurogenic atrophy is more severe. It occurs when there is disease or injury to a nerve connected to the muscle. Unlike disuse atrophy, which can occur slowly over time, neurogenic atrophy can occur suddenly.