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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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.