Background: Upper lip rejuvenation is achieved by a large variety of different treatment approaches that clearly lack a unified theoretical background of the aging processes of the upper lip complex. In this study, the histological changes that occur in the aging upper lip were systematically evaluated for the first time.
Methods: Histological cross-cuts of the upper lip complex of 20 individuals in two age groups, young (<40 years, n = 10) and old (>80 years, n = 10), were analyzed. The specimens were collected during the autopsies of individuals with no facial injuries. Hematoxylin-eosin and elastica van Gieson staining was performed, and the relevant anatomical structures were measured and compared using Student's t test.
Results: Histomorphometric analysis revealed statistically significant thinning of the cutis, thinning of the orbicularis oris muscle, and an increase of the orbicularis oris muscle angle defining the vermilion border in the old lip group. Elastic and collagen fibers in the cutis undergo degeneration processes during aging. The orbicularis oris muscle is not subject to fatty or fibroblastic degeneration, but shows signs of atrophy.
Conclusions: The histomorphometric and histomorphological analyses shed light on the, so far, only unsystematically and episodically described process of upper lip aging on a histological level. The distinct changes add further evidence to the theory that the aged look is due to a loss of elasticity and resultant ptosis of the upper lip rather than to often-postulated but unproven total volume loss.