Superficial facial muscle fiber attached to dermis

The superficial facial muscle fibers attached to the dermis refer to portions of the muscles of facial expression (e.g., zygomaticus major, orbicularis oris, platysma) that interface with the underside of the skin via a structure known as the superficial musculoaponeurotic system (SMAS). In certain facial regions (notably medial to the nasolabial fold), histological studies show that muscle fibers from mimetic muscles extend up to or into the dermis, forming a strong direct attachment. This allows contraction of these muscles to produce visible movements and expressions in the overlying skin. The SMAS is a connective tissue layer unique to the face, mediating the transmission of muscle force to the skin and serving as an important surgical plane for facial cosmetic and reconstructive surgery.

Other names

SMAS-dermal attachmentsuperficial mimic muscle-dermis connectionSMAS facial muscle insertion