5 Care must be taken to avoid confusing muscle cramps with other phenomena including central hyperexcitability (eg, dystonia, spasticity, seizures, and stiff person/stiff limb syndromes) and peripheral processes, including tetany, myokymia, myotonia, neuromyotonia (focal muscle stiffness), or myalgia. 4 Colloquially, muscle cramps are known by a number of different terms depending on the country, including charley horse in the US, chopper in England, and corky in Australia. 3 The conventional definition of a muscle cramp is a painful contraction of a muscle or muscle group, relieved by contraction of antagonist muscles. 1,2 It is important to distinguish between myogenic and neurogenic muscle cramps, because each has unique pathophysiology and management. A muscle cramp is a hyperexcitable neurologic phenomena of excessive, involuntary muscle contractions.