In order to effectively rejuvenate the aging face, it is necessary to understand the dynamic aging process and how it affects each facial structure. Much is known in regards to how the face loses volume as the soft-tissue structures age. Epidermal thinning and the decrease in collagen cause skin to lose its elasticity. Loss of fat, coupled with gravity and muscle pull, leads to wrinkling and the formation of dynamic lines. These factors contribute to the formation of jowls, crow's feet and the drooping appearance of aged facial skin. The aging process also affects the facial bones through bone resorption. There are various studies, from the analysis of male skulls, suggesting maxillary clockwise rotation and the enlargement of the bony orbit with age. In this multi-part study we will demonstrate how the various bony aspects of the face change with age in both men and women and what affects that may have on the application of facial cosmetic surgery.

Facial bone computed tomography (CT) scans were obtained from 60 Caucasian patients, (30 female, 30 male). There were ten male and ten female patients in each of three age categories (25-44, 45-64, and 65+). Each CT scan underwent 3D reconstruction with volume rendering and the following measurements were obtained: glabellar angle (maximal prominence of glabella to nasofrontal suture), pyriform angle (nasal bone to lateral inferior pyriform aperture), and the maxillary angle (superior to inferior maxilla at the articulation of the inferior maxillary wing and alveolar arch). Each angle was taken in reference to the sella-nasion line. The area of the nasal aperture was also measured on each 3D model. The data was then analyzed with a two-tailed Student's t-test, and results were considered significant at a p-value less than .05.

The glabellar angle in our female population had a statistically significant decrease from the young to middle age group, while our male population had a significant decrease from the middle to oldest age group. The maxillary angle showed significant decreases between all age groups for both genders, with the angle be greatest in the young age group. The pyriform angle did not show significant change between age groups for either gender. There was a significant increase in nasal area between all age groups for both genders, with the area being greatest in the oldest age group.

The decrease in glabellar angle found in this study suggests that the supra-orbital bar and nasion recede with age. This bony change may result in the appearance of brow ptosis and lateral orbital hooding noticed in the older population. The eyebrows appear to droop below the receded orbital rim and the upper eyelid skin appears deflated. The maxillary angle decrease may be responsible for the malar fat pad sliding down and forward, causing it to push up against the nasolabial crease, thus making it more prominent. The increase in the nasal area makes it evident that the bone recedes around the pyriform aperture, which may result in the appearance of nose elongation and drooping noticed with aging. These results suggest that the bony elements of the mid face change dramatically with age and coupled with soft-tissue changes lead to the appearance of the aged face. Thus, we feel the most effective approach towards facial rejuvenation should be two-fold: restoring volume to compensate for the loss of bony volume, and lifting and reducing the aged and less elastic soft tissue envelope. A balanced approach to facial rejuvenation between volume augmentation and soft-tissue envelope repositioning and reduction will hopefully avoid the distortions of either approach alone.