• Visible changes in the aging face (such as jowls, sagging, crow’s feet) are, in part, due to thinning skin that has lost its intrinsic elasticity and nonuniform loss of subcutaneous fat.
• The bony skeletal provides the framework on which the skin, subcutaneous fat, and muscle layers create the overall three-dimensional facial contour.
• The aging facial skeleton undergoes predictable resorption of bone, most notably an increase in the volume of the bony orbit, retrusion of the maxilla, and decrease in size of the mandible.
• Better understanding of these changes can help direct rejuvenation efforts.
Introduction
The characteristics of the aging face are a combination of structural changes on many levels. The most visible layer, the skin, comprises a variety of cells, including keratinocytes, collagen, and elastin, which produce the nonuniform thickness of the epidermis and the dermis. The alteration and decrease in the number of these cells produces the thin and atrophic appearance of the aging face. The underlying subcutaneous layer is also nonuniform in thickness, and the predictable losses in specific locations make the separating “lines” of retaining ligaments more visible with aging. Traditionally, facial rejuvenation techniques have focused on the restoration of the skin and soft tissue deficiencies with lasers, lifting, fillers, and/or fat grafting. However, for facial rejuvenation to achieve its maximum benefit, it must address all anatomic components of the aging face.
Specifically, the bony skeleton undergoes unique and predictable changes. For some patients, this may represent the primary contribution to their aging appearance. The areas most impacted by resorption of bone include the superomedial and inferolateral bony orbit, the glabellar and maxillary angle of the midface, and the mandibular body and angle measurements. , Better understanding of the location and timing of these bone changes can provide a more specific approach to correcting the aging face.
Skeletal changes
Bony orbit
The bony orbit is described as a curvilinear, quadrangular pyramid made up of seven bones. Our understanding of how this structure changes with aging continues to evolve. Studies conducted by Pessa et al. concluded that the bony orbit changes to a posterior position in relation to the cornea, with a nonsignificant increase in vertical, oblique height. , In a follow-up study, Pessa et al. concluded that the orbital rims do not, in fact, move posteriorly. This was found by measuring the orbital angle. Orbital angle was defined as the angle created from the intersection of the midpoint of the superior and inferior orbital rims in relation to the sella–nasion. Pessa et al. revisited the changes of the orbital rim and noted the specific location of bone resorption at the superomedial and inferolateral segments. In addition to rim changes, the overall volume of the orbit was noted to increase significantly with age.
In the computed tomography (CT) analysis of the changes in the facial skeleton, Shaw et al. used a curvilinear analysis to measure incremental rim changes ( Fig. 13.1 ). They noted a statically significant increase in the distance at the superomedial rim along the 10-to-60 axis in females and the 10-to-40 axis in males. The inferolateral rim distance increased significantly along the 60-to-90 axis in females and the 50-to-90 axis in males. These changes were noted to occur between the young to middle age categories for females and the middle to old categories for males.
Shaw et al. also found that the orbital aperture width, as measured from the “posterior lacrimal crest to the frontozygomatic suture,” increases significantly in females from young to middle age and in males from young to old age. The orbital aperture area also increases, with changes in females noted between young age and middle age and in males between middle age and old age.
Midface and glabella
The youthful midface is noted to have minimal to no glabella crease, full and rounded cheeks with a smooth contour, and soft nasolabial folds. With the collapse of the bony foundation, the overlying skin and soft tissue exhibit very characteristic features of aging. These changes include the drooping of the inferior orbital soft tissue or tear-trough deformity, flattened zygomatic prominences, downward draping skin, marionette lines, and deepening of nasolabial folds. , ,
Shaw et al. measured several dimensions of the midface to determine the location and timing of the midface collapse. The retrusion of the midface was measured by using the glabellar angle, pyriform angle, and maxillary angle. “The angle formed by the line from the maximal prominence of the glabella to the nasofrontal suture and the sella–nasion line gives the glabellar angle. The angle between the line of the nasal bone to lateral inferior pyriform aperture and sella–nasion forms the pyriform angle. The angle between the line of the superior to inferior maxillary wing and alveolar arch to the sella–nasion forms the maxillary angle” ( Figs. 13.2 and 13.3 ).
