SMAS (Superficial Musculo-Aponeurotic System)

The SMAS (Superficial Musculo-Aponeurotic System) is a fibrous sheet of connective tissue that lies under the skin of the face and links the facial muscles to the overlying skin. It spans the cheeks, temples and into the neck and plays a key role in how facial expressions and gravity affect surface contours over time.

In facial surgery, particularly facelifts, surgeons commonly manipulate the SMAS to lift and support deeper tissues rather than relying only on skin tightening; treating this layer often yields more durable and natural results. Approaches that modify the SMAS, such as plication, excision or deep-plane techniques, have different benefits and risks, and patients should expect temporary swelling, bruising and possible transient nerve changes during recovery.