cramp

The cramp - A painful spasm in a muscle that is caused by excessive and prolonged contraction of the muscle fibres. The affected muscle may feel hard and tender. Cramps often occur as a result of increased muscular activity, which causes a build-up of lactic acid and other chemicals in the muscles, and leads to small areas of muscle-fibre damage.

Repetitive movements, such as writing (see cramp, writer’s) or sitting or lying in an awkward position may also result in cramps. In addition, cramps may follow profuse sweating because loss of sodium salts disrupts muscle cell activity.

Massaging or stretching the muscles involved may bring relief. A drug containing calcium or quinine may be given for recurrent night cramps. Recurrent, sudden pain in a muscle not associated with hardness of the muscle may be caused by peripheral vascular disease.