What term refers to an involuntary contraction or twitching of muscles?

The term that refers to an involuntary contraction or twitching of muscles is fasciculation. Fasciculations are small, involuntary muscle contractions that can be visible on the surface of the skin. They often occur when a muscle is at rest and can be caused by various factors, including muscle fatigue, irritation of nerves, or certain neurological conditions.

While cramps, spasms, and dystonia are also related to muscle contractions, they describe different phenomena. Cramps typically refer to a painful, prolonged contraction of a muscle, while spasms are a sudden, involuntary contraction that can affect a larger area of muscles, often causing pain or discomfort. Dystonia refers to sustained muscle contractions, often resulting in twisting or abnormal postures, which is distinct from the brief, twitching nature of fasciculations. Understanding these distinctions is important in the study of muscle physiology and associated conditions.