The quest for the hallmarks of eternal youth - plump skin and a baby-faced firmness - is unfortunately one that can never be totally sustained, but it can be held on to longer with some understanding of the physical and environmental concerns that age the face. Hollows and gauntness due to loss of volume, shrinkage of the bone structures, loss of collagen, elasticity and gravity are all characteristics of the ageing face. While some of the skin-related factors can be reined in with healthy lifestyle choices and a good product regime, many of the characteristics are a matter of genetics. However, all can be more effectively managed via an understanding of the ageing process.

Ins and Outs

Cutaneous aging is caused by two distinct processes - intrinsic and extrinsic factors.Intrinsic, or chronologic aging, is the inevitable genetically determined process that naturally occurs. Intrinsic ageing is determined by our genetic clock and is affected by the degenerative effects of free radicals and the body's inability to perfectly repair their damage. Over time our cells, tissues and vital organs ‘rust' or deteriorate. These internal changes to the muscle, fat and bones are not as visible as the signs of ageing on the external organ - our skin. Our skin shows the wear and tear of extrinsic aging, which is environmentally induced and manifests in age-associated skin changes including thinning, laxity, fragility and wrinkles. In addition, sun-exposure leads to dyspigmentation, premature wrinkling, telangiectasia and actinic elastosis.

Intrinsic aging is a continuous process that usually begins in our mid-20s but doesn't become evident for decades. In our twenties collagen production begins to slow and elastin has a bit less spring. Dead skin cells do not shed as quickly and turnover of new skin cells decreases. The apparent signs of intrinsic aging include the loss and descent of underlying fat leading to hollowed cheeks and eye sockets, loss of firmness and the bones shrink away from the skin due to bone loss, which causes sagging skin.

The extrinsic, or preventable environmental factors that magnify intrinsic aging, often act together with the normal aging process to prematurely age our skin. Most premature aging is caused by sun exposure, though others are repetitive facial expressions, gravity, sleeping positions and smoking.

Lines and creases form over major and minor joints, as a result of skin contractions that lie perpendicular to the underlying muscular vector force. However, relaxed skin tension lines (RSTL) are formed during relaxation and are created by the natural tension on the skin from underlying structures.

Structural changes

Recent studies have shown the shrinking of facial bones also plays a role in ageing the face. Evidently, facial bones remodel their three-dimensional shape with age, showing the most pronounced difference measured in the T-zone.

In women the area between the brows and top of the nose (the glabellar angle) is shown to decrease as the area under the rim of the eyebrows retreats, resulting in sagging brows and deflated eyelid skin. In men the glabellar angle decreases and the area supporting the cheeks (maxillary angle) is also shown to decrease. Second to this, the malar fat pad, responsible for cheek fullness, slides down and forward, pushing against the nasolabial fold and making the maxillary angle appear more pronounced.

Lastly, the pyriform angle (the opening of the nose) showed receding bones causing the appearance of an elongated nose and drooping in the surrounding area. The nasal area increases significantly with age.

Volumetrics

Facial ageing is reflective of dynamic and cumulative effects of time on the skin, soft tissues and deep structural components of the face. It's a complex synergy of skin textural changes and loss of facial volume. Many of the facial manifestations of ageing combine the effects of gravity, progressive bone resorption, decrease in tissue elasticity and redistribution of subcutaneous fullness.

A good way to assess the changing forms of aging is to divide the face into the upper third (forehead and brows), middle third (midface and nose), and lower third (chin, jawline, and neck). The midface is important in facial aesthetics because perceptions of beauty are found largely in the synergy between the eyes, nose, lips, and cheek bones (central facial triangle). For aesthetic reasons we should consider this area from a three-dimensional rather than two-dimensional perspective. Therefore restoring a youthful three-dimensional facial landscape should be considered the primary goal in facial rejuvenation.

In recent years we've seen a marked increase in the number of non-surgical procedures aimed at facial rejuvenation. Patients are now offered alternatives to the more traditional surgical procedures that focus on restoration of lost facial volume.

Three changes of the ageing face explained

As the human face ages our facial shape changes. Some are straightforward to address, while others are difficult technical challenges. Although every face ages differently, there are three common themes noted in all aging faces.

Descent of facial fat

As we age, facial fat descends causing facial shape to change. The youthful face is typified by full, well-supported fat. Volumetric highlights are found in facial aesthetic sub-units that have a high density of retaining ligaments (malar, preparotid, and orbital rim) and serve to fixate this volume of fat to underlying structures. Together with the volumetric fullness of the malar and preparotid region is a concave in the submalar region that lays over the buccinator muscle and buccal recess. This pairing of fullness and concavity and a well-defined mandibular accounts for the angular, tapered appearance of the youthful face.

In middle age, as this ligament support reduces, facial fat volumetrically comes forward and descends in the cheek, producing a squarer facial contour with less distinction between malar highlights and midfacial fat. This lowering of the facial fat means older faces appear vertically longer than young faces.

Volume loss

Young faces are full of well-supported facial fat which, over time, deflates. This deflation is most apparent in regions with a high density of retaining ligaments, which are typically volumetrically full in youth (malar, preparotid, lateral and infraorbital rim, and lateral chin).

Along with facial deflation comes a laxity in soft tissue caused by diminished support. Young faces have a smooth transition between the contours of the face while middle-aged faces develop lines of differentiation between regions. The treatment plan to improve the ageing face should involve repositioning of soft tissue and restoring volume along with blunting these defining lines.

Radial expansion

Facial aging is not all vertical, the soft tissue that occurs along specific areas of the midface also undergoes radial expansion. Where the skin and underlying subcutaneous fat are densely attached to the deep facial fascia by retinacular fibres that weave in the skin, subcutaneous fat and superficial fascia and deep fascia and muscle.

Over time the expressions we make with our faces cause the skin along the nasolabial line to disrupt the subcutaneous fat, disrupting these attachments. This forces the skin and fat lateral to the nasolabial fold to expand radially and fall out from the skeleton, explaining much of the nasolabial fold prominence in the aging face. Radial expansion lateral to marionette lines also accounts for some of the jowling.

Vectors

Facial aging changes are commonly represented by vectors of which gravity, radiation damage and natural aging contribute to soft-tissue ptosis. These vectors are predictable and common to all individuals. A vector is defined by Webster's as "a quantity that has magnitude and direction and that is commonly represented by a directed line segment whose length represents the magnitude and whose orientation in space represents the direction."

Digital technology has provided physicians with the ability to virtually age a young individual by selectively inducing aging changes that relate to realistic vector change.

While the exact anatomy and physiology of these vectors vary from source to source, there are basic principles that can be agreed on.

The most noticeable vectors of aging involve the forehead, brow, and upper eyelids, with skeletal shrinkage included as a contributor to skin laxity. The frequent movement of the brow elevators and depressors produce predictable horizontal, vertical, and oblique wrinkles and drooping in the brow and forehead. The youthful areas that will become ptotic are hard and soft-tissue changes that occur in nature. These include ptosis of the lower lids and chin, descent of the malar fat pad (cheeks) and nasal tip, accentuated nasolabial folds, shortening or attrition of the teeth, elongation of the upper lip, excess and damaged neck skin and a general squaring of the youthful, oval face outline. The concept of vectors of aging and their surgical correction is a controversial means of describing aging and surgery, mainly because it uses a two-dimensional system to describe a three-dimensional process. However, appreciation of the mechanics of aging and its related correction is essential in providing natural-appearing surgical results.

Skin: a chronology

Epidermis
The uppermost layer of the skin, the epidermis, renews itself constantly. However, as a person ages the cells of the epidermis become thinner and less sticky, making the skin appear noticeably thinner. This diminishing lessens the effectiveness of the natural barrier function, resulting in dryness. Production of epidermal cells also decreases by 10 per cent each decade and they divide more slowly as we age, making the skin less able to repair itself quickly.

Dermis
Between the epidermis and the subcutaneous fat layer lies the thick dermis layer, which contains connective tissue and houses the arteries, hair follicles, lymph vessels, sensation receptors, sweat glands and veins. The effects of aging are significant in this layer as, not only does the dermal layer thin out, but also produces less collagen and the elastin fibres wear out. This depletion of the skin's scaffolding causes wrinkles and sagging. Second to this, drying becomes an issue as sebaceous glands enlarge but produce less sebum, and the number of sweat glands decreases.

Subcutaneous
Finally, the deepest layer of fatty tissue and collagen lies below the skin and gives it structure. Here, fat cells get smaller with age leading to more noticeable wrinkles and sagging because the fat cells cannot infill the damage from the other layers.

Ageing gracefully

While a large part of the ageing process is predetermined by genetics and lifestyle, the ageing process can be reduced by recognising healthy lifestyle factors such as sun protection, a healthy diet and exercise regime, and managing stress. Taking a proactive approach can have you feeling that age is indeed just a number.