Tremor is a rhythmic, involuntary muscular contraction characterized by oscillations (to-and-fro movements) of a part of the body. The most common of all involuntary movements, tremor can affect various body parts such as the hands, head, facial structures, vocal cords, trunk, and legs; most tremors, however, occur in the hands. Tremor often accompanies neurological disorders associated with aging. Although the disorder is not life-threatening, it can be responsible for functional disability and social embarrassment.