EMG: Electromyogram. A test that is used to record the electrical activity of muscles. When muscles are active, they produce an electrical current. This current is usually proportional to the level of the muscle activity. An EMG is also referred to as a myogram. EMGs can be used to detect abnormal muscle electrical activity that can occur in many diseases and conditions, including muscular dystrophy, inflammation of muscles, pinched nerves, peripheral nerve damage (damage to nerves in the arms and legs), amyotrophic lateral sclerosis (ALS) (also known as Lou Gehrig disease), myasthenia gravis, disc herniation, and others.

Electrical Muscle Stimulation: Physiological therapeutic introduction of electrical stimulation at a predetermined frequency, intensity and rate for the purpose of achieving a physiological response.

End Plate: The cartilage found between the bone of the vertebrae and the disc, to serve as attachment point for the fibers of the disk.