Surface Electromyography or SEMG is the study of muscle status (activity) using surface electrodes. As opposed to using an invasive needle EMG which measures a single muscle fiber, SEMG picks up tiny signals coming through the skin that are representative of the average of multiple fibers of a given muscle. The data is obtained throughout the surface electrodes much like the EKG electrodes, amplified, and sent to the computer where it is displayed.
Myotronics pioneered this science with the inception of its first SEMG unit in 1981, the current system we use permits the study of up to eight channels of SEMG simultaneously. Dr. Sahota believes that muscle palpation is subjective and an objective measurement can be invaluable in knowing the muscle status of the head and neck. This can help aid in occlusal diagnosis (bite issues), since muscles play a critical role in tempero-mandibular joint disorders.
SEMG also enables studies of muscle function and patient education.