Fibrillation

A small, localized, irregular and involuntary muscle contraction involving single muscle fibers that is ‘finer’ than that produced by fasciculation.  Most often evident in neural lesions involving motoneurons, peripheral nerves and spinal roots.  Remains until nerve becomes re-innevated or fibrotic (development of excess fibrous connective tissue).  Fibrillation potentials measure derived from EMG have not been shown to be diagnostic of denervation.        

See Denervation, Electromyography (EMG), Fasciculation, Muscle fiber