Superficial muscular aponeurotic system (or superficial musculoaponeurotic system) (SMAS) is a thin yet tough unitary tissue plane of the face formed by facial fasciae, subcutaneous connective tissue, and facial muscles.
Clinical significance
The SMAS is clinically important in facial plastic surgery for rhytidectomy (facelift procedure). During this procedure, the SMAS is accessed through an arch-shaped incision anterior to the ear; a portion of the SMAS is then excised and the remaining SMAS is stretched by drawing it posterior-ward and suturing it, thus making the skin of the face which overlies the SMAS taut.