Tremor

Tremor: Muscle Action

Tremor refers to the involuntary, rhythmically repetitive contraction of opposing muscle groups. It is a very rapid sequence of tension and relaxation of muscle parts. Commonly affected areas include the jaw, upper body, hands, or even the voice.

The causes can be varied, such as cold, emotional tension (excitement), fever, caffeine, drug withdrawal, side effects of medications, hypoglycemia, epileptic seizures, or Parkinson's disease.