The SMAS and the nasolabial fold

Area of Science:

• Anatomy
• Plastic Surgery
• Facial Rejuvenation

Background:

• The superficial musculoaponeurotic system (SMAS) is a critical facial anatomical layer.
• Understanding SMAS attachments is vital for effective rhytidectomy techniques.
• Previous studies highlight SMAS importance, but specific muscular attachments in the medial cheek require further elucidation.

Purpose of the Study:

• To investigate the anatomical relationship between the SMAS and the zygomaticus major and minor muscles.
• To elucidate the role of SMAS attachments in facial flap mechanics during rhytidectomy.
• To explain the observed minimal changes in the nasolabial crease following Skoog-type sub-SMAS facelifts.

Main Methods:

• Histologic examination of serial sections.
• Clinical dissections.
• Cadaver dissections.

Main Results:

• The SMAS was identified as the investing fascia of the zygomaticus major and minor muscles in the medial cheek.
• SMAS attachment to these muscles diffuses traction applied to the cheek flap during rhytidectomy.
• This anatomical arrangement correlates with minimal alteration of the nasolabial crease post-Skoog-type sub-SMAS facelift.

Conclusions:

• The SMAS's investing fascial role on the zygomatic muscles is a key factor in rhytidectomy outcomes.
• This anatomical finding provides a mechanistic explanation for the stability of the nasolabial crease after sub-SMAS facelifts.
• The study reinforces the significance of understanding detailed facial anatomy for optimizing surgical results in facial rejuvenation procedures.