ABSTRACT
The “superficial muscular and aponeurotic system (SMAS)” is a fascial layer in the parotid and cheek regions which is described in classic anatomy textbooks such as Gray's textbook of anatomy. Facial dissection shows that the SMAS is stretched both superiorly and inferiorly. The SMAS is kept tensed superiorly by the superficial temporal muscles, the external part of the frontalis muscle, and the orbicularis oculi muscles. It is tensed inferiorly by the platysma muscle and attached posteriorly to the tragus and the mastoid area. Microscopically the SMAS is composed of one to three layers between the parotid fascia proper and the skin. Sometimes the muscular fibers are obvious within the fibrous layer hence the term muscular-aponeurotic system. In the parotid area, only sensory nervesare located within the dermis and the SMAS. The facial nerve and its branches run deep into the parotid glands and are protected by the parotid fascia and the external lobe of the gland.
