cramp, painful uncontrollable contraction of a muscle or group of muscles. The type that results from cold, strain, or disturbance of circulation (as experienced by swimmers) is eased by massage and the application of heat. Cramp in the abdominal or skeletal muscles brought on by hard physical exertion in extremely high temperatures (e.g., in miners, stokers, or firemen) because of loss of salt from the body during profuse perspiration can last for hours or days if untreated. Such cramps are considered to be a type of heat exhaustion. A cool atmosphere and the replacement of salt and water orally or intravenously is required, and application of heat is not recommended. Heat cramps in persons who do heavy labor can be prevented by the addition of salt to drinking water or by taking salt tablets. Contraction of muscles in a hollow organ is known as colic. A stitch in the side is due to a cramp in the muscles between the ribs.

Painful, involuntary, sustained contraction of muscle in limbs or some internal organs. Causes may be neurological, reflex, or psychological. Common muscle cramps include swimmer's cramp from overexertion in cold water, heat cramps from loss of salt in sweat, leg cramps, and occupational (e.g., writer's) cramp. Menstrual cramps are uterine muscle contractions before or during menstruation. Cramps occur in diseases including parkinsonism and Huntington chorea. Tetany is severe cramping noticed first in limb muscles.

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Cramp-rings are rings anciently worn as a cure for cramp and "falling-sickness" or epilepsy. The legend is that the first one was presented to Edward the Confessor by a pilgrim on his return from Jerusalem, its miraculous properties being explained to the king. At his death it passed into the keeping of the abbot of Westminster, by whom it was used medically and was known as St Edwards Ring. From that time the belief grew that the successors of Edward inherited his powers, and that the rings blessed by them worked cures.

Hence arose the custom for the successive sovereigns of England each year on Good Friday formally to bless a number of cramp-rings. A service was held; prayers and psalms were said; and holy water, which had been blessed in the name of the Father, Son and Holy Ghost, was poured over the rings, which were always of gold or silver, and made from the metal that the king offered to the Cross on Good Friday. The ceremony survived to the reign of Queen Mary, but the belief in the curative powers of similar circlets of sacred metal has lingered on even to the present day.

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