Wrinkles and sagging result not only from changes in the skin, but also from aging-related changes in the facial bones, says a new study.
Robert B. Shaw, Jr. and colleagues of the University of Rochester Medical Center, analyzed computed tomography scans of the facial bones in young (age 20 to 40), middle-aged (41 to 64), and older (65 and up) age groups.
The detailed measurements in three-dimensional reconstructions of the CT scan showed some important differences in the facial bone structure (or facial skeleton) between age groups.
"The facial skeleton experiences morphologic change and an overall decrease in volume with increasing age," wrote the researchers.
One prominent change was an increase in the area of the "orbital aperture"-that is, the eye sockets. In both men and women, the eye sockets became wider and longer with age.
Aging also affected the bones of the middle part of the face, including reductions in the glabellar (brow), pyriform (nose), and maxillary (upper jaw) angles.
The length and height of the mandible (lower jaw) decreased with age as well. Although these changes occurred in both sexes, many occurred earlier in women-between young and middle age. In men, most of the changes occurred between middle age and old age.
"The bony components of the face are important for overall facial three-dimensional contour as they provide the framework on which the soft-tissue envelope drapes," wrote the researchers.
By using materials and techniques for skeletal augmentation, plastic surgeons can improve the outcomes of facial rejuvenation, they noted.
The findings appeared in the January issue of Plastic and Reconstructive Surgery, the official medical journal of the American Society of Plastic Surgeons.