There has been considerable disagreement in descriptions of the SMAS.
Fresh cadaver dissection, combining anatomic dissection done with the
aid of the operating microscope and histologic cross section of facial
tissues, was performed in 24 facial halves. Histologic preparation wa
s made on tissue macrosections, each 10 cm in length. Consistent findi
ngs include the following: (1) Although the SMAS is closely applied to
the superficial surface of the parotid gland, a thin but distinct par
otid fascia can be identified between parotid gland and SMAS. (2) The
SMAS terminates superiorly within 1 cm below the zygomatic arch, and i
s,not continuous with the temporoparietal fascia. (3) The SMAS in the
cheek lies in continuity with the orbicularis oculi muscle of the lowe
r eyelid. (4) Considerable variability exists in the histologic appear
ance of the SMAS in different facial regions within a single cadaver,
as well as in a given facial region between cadavers. Because of its v
ariability, histologic identification of the SMAS should be made in co
ntinuity with known reference structures, such as the platysma.