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Superficial Musculo-Aponeurotic System
Connective Tissue

Superficial Musculo-Aponeurotic System


The superficial musculo-aponeurotic system (SMAS) is the collective name for the superficial fascial structures of the face into which the muscles of facial expression insert. Histologically, this fascia is composed of fibroelastic tissue with the elastic content decreasing with age, leading to sagging of the facial skin over time. Traction of the SMAS has become standard technique in aesthetic facial surgery (Stecco & Hammer, 2014).

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Anatomical Relations

The SMAS is continuous superiorly with the galea capitis and caudally with the platysma muscle. It fills in the spaces around other facial structures; thus its relations are ill-defined. Rather it is found in different thicknesses across the face.


The SMAS connects facial muscles to the skin allowing for facial expression.

List of Clinical Correlates

—Cosmetic surgery


Stecco, C. & Hammer, W. I. (2014) Functional Atlas of the Human Fascial System E-BookElsevier Health Sciences.

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Superficial Musculoaponeurotic System

ScienceDirect image

The SMAS is described as a midlevel fibromuscular layer separating the deep facial fat from the superficial facial fat.

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