fasciculation

Full Definition

Fasciculations are brief, involuntary contractions of muscle fibers that appear as visible twitches or ripples under the skin. They result from spontaneous discharge of motor neurons or their axons and can be benign or pathological. In neurological practice, fasciculations may indicate lower motor neuron disease, such as amyotrophic lateral sclerosis (ALS), or may be benign phenomena related to fatigue, stress, or caffeine intake. Clinical context and associated findings are crucial for determining their significance.

Usage

Usage note: Distinguish from fibrillations, which are typically not visible and require EMG for detection.

In Context

• "Electromyography confirmed the presence of fasciculations in the affected muscles." — EMG report
• "The patient noticed fasciculations in his calf muscles over the past month." — Neuromuscular clinic note