The morphologic changes our faces undergo with age are the result of a complex interplay between the underlying craniofacial skeleton, our mimetic musculature, compartmentalized facial fat, facial retaining ligaments, and our skin envelope. Changes in each of these components contribute, at least in part, to the characteristic stigmata of the aged face.
With age, there is an overall reduction in both dermal organization and thickness. This is driven largely by a decrease in the total collagen content of our skin, resulting in thinning of our skin with age. In addition, the proportion of immature type III collagen in our skin increases and there is a depletion of normal elastic fibers within the dermis beginning at approximately age 30. It is these intrinsic degenerative changes, compounded by actinic damage, that contribute to the loss of physiologic recoil, increased skin laxity, and fine rhytides characteristic of the aged face.
The age-related changes our facial skeletons undergo with time are thought to include a reduction in facial height, an increase in facial width, and maxillary retrusion secondary to bony resorption—resulting in a downward and inward rotation with respect to the cranial base. This clockwise rotation of the maxilla is believed to contribute to the disruption of the smooth transitions between facial convexities through its effect on the facial retaining ligament system. Although these theories have been studied extensively, the concepts have never been demonstrated in a single cohort of patients longitudinally.
The changes our midface soft tissues undergo with age are an area of great interest to aesthetic surgeons, as it is the soft tissue we most often target during attempts to rejuvenate the aged face. Numerous studies have attempted to quantify these changes and have led to two predominant theories in midfacial aging: the traditional gravitational theory and the more recent volume-loss theory. Stuzin et al. provided early support for the gravitational theory when they introduced the idea of retaining ligament attenuation as a cause for midface soft-tissue descent. Through historical photographs and photogrammetry, Yousif et al. concluded there is an inferior, lateral, and anterior displacement of the cheek mass with age leading to a deepening of the nasolabial fold. Lastly, more recent support for the gravitational theory of aging includes the work by Mally and colleagues, who documented a restoration of midface volume and a more youthful appearance when patients were photographed supine compared to an upright position.
Source:
Plastic and Reconstructive Surgery
