Spasm

A spasm is an involuntary contraction of a muscle or group of muscles that cannot be controlled by the patient. Some muscle spasms can cause pain in the affected area. Others can cause a twitch or tic. Severe spasms can cause convulsions.
Muscle spasms are usually the result of overstressing a muscle and can be treated with muscle relaxants, which make it more difficult for muscles to contract without voluntary control. However, some spasms are the result of serious underlying conditions.
Spasm at Wikipedia
Category:Symptoms