Atrophy / Paralysis

13.1.1 Atrophy / Paralysis When a muscle does not work, it shrinks and weakens, which is called atrophy.

Injuries as a cause of atrophy A common reason for atrophy is injuries.

1. Paralysis. This is the term used when a limb cannot move. This is often due to damage to the nerves that are connected to the muscle, or damage to the main nerve (spinal cord) in the backbone.

1. Serious injury to bones or joints (e.g. fractures or arthritis) may make the animal unable to use its muscles, and then the muscle shrinks (i.e. atrophy). If the animal recovers, and begins to use its muscle, it may regain its normal size again. For a complete discussion of paralysis, see page 259.

1. Atrophy may result from an injury to the muscle itself, to the tendons which attach to it, or to the blood vessels which go to and from the muscle.

Nutritional deficiencies as a cause of atrophy Certain vitamins and minerals (e.g. vitamin E and selenium) are necessary for muscles to function properly. If vitamin E and/or selenium is deficient in the diet of young calves and lambs, the muscles cannot work properly. In these cases, paralysis can occur without any sign of injury.