A<unk>  is a sudden, involuntary muscle contraction or overshortening; while generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the affected muscle. Muscle<unk> s are common and are often associated with pregnancy, physical exercise or overexertion, age (common in older adults), or may be a sign of a motor neuron disorder.<unk> s may occur in a skeletal muscle or smooth muscle. Skeletal muscle<unk> s may be caused by muscle fatigue or a lack of electrolytes such as sodium (a condition called hyponatremia), potassium (called hypokalemia), or magnesium (called hypomagnesemia). Some skeletal muscle<unk> s do not have a known cause.<unk> s of smooth muscle may be due to menstruation or gastroenteritis. Motor neuron disorders (e.g., amyotrophic lateral sclerosis), metabolic disorders (e.g., liver failure), some medications (e.g., diuretics and inhaled beta‐agonists), and haemodialysis may also cause muscle<unk> s. A<unk>  usually starts suddenly and it also usually goes away on its own over a period of several seconds, minutes, or hours. Restless leg syndrome and rest<unk> s are not considered the same as muscle<unk> s.
Cramp
Punding
Jungle Rot
Lint 
Jim 
Uinyeo
Lanugo
Sharsheret 