PATTERNS OF COORDINATED LOWER FACIAL MUSCLE FUNCTION AND THEIR IMPORTANCE IN FACIAL REANIMATION

Coordinated patterns of lower facial muscle activity have been observe d using 8-channel electromyography (surface electrodes in a bipolar co nfiguration) on 11 healthy volunteers to provide a picture of the patt erns of muscle activity during function. Measurements of integrated el ectrical activity were made to allow comparison of different muscle gr oups during active, active-against-resistance, and passive movements. A contraction reflex was assessed by an electromechanical device and n oted in 8 of 11 subjects. Lower facial movements were found to involve simultaneous bilateral activity in all the muscle groups tested bilat erally and to require a balance between dilator and constrictor forces . The significance for facial reanimation surgery is that it is desira ble to reconstruct balanced constrictor and dilator forces, the latter having vector pulls upwards, downwards and laterally to reconstruct t he normal mechanism of lower facial movement.