A fibrillary tremor, also called fasciculation, refers to an involuntary muscle twitching characterized by quick, subtle movements beneath the skin's surface. There exist several synonymous terms for this condition, such as muscular fasciculation, fine muscle fasciculation, or simply muscle twitching. While fibrillary tremor typically involves small groups of muscle fibers, it can occur in any part of the body, causing tremors in the limbs, face, or even the tongue. Fasciculations often arise due to nerve damage or muscle disorders like amyotrophic lateral sclerosis (ALS). Although fibrillary tremors can be unsettling, they are generally harmless and can be managed through stress reduction, relaxation techniques, and in some cases, medication.