The nasolabial fold: an anatomic and histologic reappraisal.

The nasolabial fold was analyzed by anatomic and histologic evaluation of the tissue planes that create and surround the fold. A fascial-fatty layer exists in the superficial subdermal space extending from the upper lip across the nasolabial fold to the cheek mass. The SMAS is present in the upper lip as the superficial portion of the orbicularis oris muscle. Traction on the SMAS or periosteum lateral to the nasolabial fold can deepen the fold, while traction on the fascial-fatty layer lessens the fold. The fascial-fatty layer and skin of the cheek mass are suggested as the primary ptotic elements responsible for facial aging.