The human face tends to transition from a more triangular or oval shape in youth to a squarer, wider contour with age. This change in facial geometry is not merely a superficial phenomenon of sagging skin, but a complex process affecting the entire structure of the head and face. The widening appearance results from simultaneous physiological changes involving the underlying skeletal foundation, the movement and volume of fat, and alterations in the overlying soft tissues like muscle and skin.
Skeletal Remodeling: The Foundation Changes
The facial skeleton, which provides the primary framework, undergoes continuous changes throughout life, a process known as remodeling. This bony transformation contributes to the perception of a wider, heavier lower face as the years pass. Unlike the rest of the skeleton, certain facial bones experience both resorption (loss of bone) and apposition (growth of bone), altering facial proportions.
The most significant changes contributing to width occur in the mandible, or jawbone. Studies have shown that the width of the jaw measurably increases with age in both sexes by an average of 4 to 5 millimeters. This outward expansion of the posterior jaw area directly creates the appearance of a broader, more squared-off jawline.
While the lower face expands in width, the mid-face region experiences changes that contribute to a flatter, broader look. The eye sockets, or orbits, enlarge due to uneven bone resorption, particularly along the rim. This expansion of the bony opening causes the overlying soft tissue to lose support and appear recessed.
The maxilla, or upper jaw bone, also undergoes remodeling, often resulting in a loss of anterior projection. This retrusion of the mid-face skeleton, combined with the widening of the jaw and orbits, shifts the overall facial contour. The combined effects of mandibular widening and mid-face flattening produce a face that appears less sculpted and more uniform in width.
Fat Pad Migration and Volume Shift
Changes in the facial fat compartments represent the second major factor contributing to facial widening and descent. Facial fat is organized into distinct pads that behave differently based on their depth. The deep fat compartments, which sit directly above the bone and provide structural padding, generally undergo atrophy or volume loss over time.
This deflation of the deep fat pads removes the underlying support structure for the superficial fat and skin. The loss of this deep volume is responsible for the hollowness often seen in the temples and under the eyes, eliminating the youthful convexity of the cheeks.
In contrast to the deep fat, the superficial fat pads, which lie just beneath the skin, tend to migrate downward and inward. Due to gravity and the loss of deep structural support, these pads descend, causing volume accumulation in the lower face, creating jowling and deepening the nasolabial folds.
This volume displacement pushes the lower facial contours outward, increasing perceived width. The movement of fat from the upper face to the lower face fundamentally alters the youthful volume distribution, replacing the upward-pointing triangle of youth with a base-down, squarer shape.
Dermal Structure and Muscle Alterations
The quality of the skin and the behavior of facial muscles act as modifiers that exacerbate the effects of underlying skeletal and fat changes. The dermis, the skin’s supportive layer, loses structural integrity due to reduced production of collagen and elastin fibers. This decline leads to skin laxity, diminishing its ability to hold the fat and muscle layers taut against the bone.
As the skin loses firmness and elasticity, it can no longer effectively resist the downward and outward forces of fat migration and gravity. This laxity allows soft tissue changes, such as jowling and displaced fat accumulation, to become more externally prominent. The slackened skin drapes over the altered bone and fat contours, making the widening effect more visible.
Alterations in the masseter muscles, the primary chewing muscles located at the angle of the jaw, can directly increase lower facial width. Chronic overactivity or hypertrophy, often linked to habits like teeth clenching or grinding (bruxism), causes these muscles to enlarge. This muscle bulk adds significant dimension to the lower face, creating a square-angled appearance that expands the width of the jawline.
External and Lifestyle Modifiers
While changes in bone, fat, and skin are inherent aspects of biological aging, external and lifestyle factors can significantly accelerate this widening process. Chronic, unprotected exposure to ultraviolet (UV) radiation is a potent environmental modifier. UV light penetrates the skin, causing damage that accelerates the breakdown of collagen and elastin in the dermis.
This sun damage, known as photoaging, prematurely weakens the skin’s supportive scaffolding, making the effects of fat migration and gravitational pull appear more pronounced. Smoking also contributes to accelerated facial aging by constricting blood vessels and reducing oxygen flow to the skin, impairing the production of healthy collagen and elastin. This reduction in tissue health compromises the skin’s ability to maintain a tight, youthful contour.
Issues within the oral cavity can indirectly influence the skeletal structure and facial shape. Long-term dental problems or the loss of teeth can alter the forces exerted on the jawbone, accelerating bone resorption and remodeling in the maxilla and mandible. The resulting loss of bone height and volume contributes to the collapse of the overlying soft tissues, exacerbating the appearance of a wider, squarer face.