The process of facial aging extends far beyond changes in the skin’s texture or elasticity. Beneath the surface, the underlying facial skeleton undergoes continuous, gradual remodeling throughout adult life. This structural shift involves a predictable loss of bone volume and density, explaining why the face changes shape over time. Recognizing that the skull’s framework is dynamic, not static, is key to understanding age-related facial transformation. These universal skeletal changes impact the contours and dimensions that support the overlying soft tissues.
The Mechanisms Driving Facial Bone Change
The continuous renewal of bone tissue, known as remodeling, involves a balanced interaction between two cell types: osteoclasts and osteoblasts. Osteoclasts break down old tissue (resorption), while osteoblasts deposit new bone material. With advancing age, this equilibrium shifts, leading to a negative bone balance where resorption outpaces formation, resulting in a net loss of bone volume.
This age-related imbalance is linked to biological factors, including changes in cellular activity and hormonal decline. The life span of bone-forming osteoblasts is reduced over time, while the activity of bone-destroying osteoclasts often increases. Hormonal shifts, particularly the decline in estrogen following menopause, accelerate this process because estrogen suppresses osteoclast activity. Consequently, the facial skeleton loses mass and volume in specific and predictable areas.
Specific Skeletal Shifts and Volume Loss
The loss of bone volume is not uniform across the face but is concentrated in areas providing projection and support. In the midface, a key change involves the maxilla, which forms the upper jaw and parts of the eye socket. The maxilla undergoes bone resorption, causing it to recede and lose forward projection, contributing to a flatter central facial appearance. Similarly, the zygomatic bones (cheekbones) experience volume loss, decreasing the definition and prominence of the malar area.
Around the eyes, the bony rims of the orbits (eye sockets) predictably widen and deepen with age. This expansion occurs as bone tissue is resorbed, particularly along the superomedial and inferolateral aspects of the rim. This remodeling fundamentally alters the structure supporting the eye and surrounding soft tissues.
In the lower face, the mandible (jawbone) experiences significant changes that alter the profile and jawline definition. Bone loss occurs notably in the prejowl area and along the inferior border, decreasing the height of the jawbone. The angle of the jaw often becomes more obtuse, meaning the lower jawline loses its sharp, youthful corner. These localized resorptive changes create a distinct, aged skeletal morphology.
How Bone Remodeling Affects Visible Aging
The predictable recession and volume loss in the facial skeleton translate directly into the visible signs of aging. As the maxilla and zygomatic bones recede, they no longer provide adequate structural support for the overlying fat pads and cheek muscles. This loss of bony foundation allows soft tissues to descend and shift, leading to sagging cheeks and the deepening of the nasolabial folds.
The widening and deepening of the orbital sockets cause the eye and surrounding soft tissues to appear sunken or hollowed. This structural change enhances the look of dark circles and shadows beneath the eyes, as less bone mass is present to hold the soft tissue forward. The lack of underlying bony support also makes the appearance of fat prolapse, commonly known as eye bags, more noticeable.
In the lower third of the face, mandibular bone loss contributes to jowling and the softening of the jawline contour. Resorption in the prejowl region creates reduced support, causing overlying soft tissue and fat to hang more prominently. This lack of definition, combined with the decreased height of the mandible, contributes to a less defined neck and chin angle.