Given the gender-specific anatomical differences that exist, it becomes clear why volume loss can masculinise a female forehead by slightly flattening the lower forehead and even creating a central area of depression. These changes can unmask the underlying bony prominences and depressions creating unwanted shadows, especially under certain lighting, that can appear unattractive in a female. Replacing volume in the forehead using cosmetic fillers helps to restore a more youthful convex contour, smoothen surfaces and reduce unwanted shadows. Fillers can also be used to provide support for the overlying soft tissue including the brows, thereby promoting a degree of brow lift (particularly if combined with other non-surgical treatments to the upper third of the face).    

The forehead frontalis muscle is the primary elevator of the eyebrows during facial expression and also plays a secondary role in upper eyelid elevation. Both the forehead fat compartments and underlying bone provide a structural foundation and “expansion force’ for the frontalis muscle. This force helps to keep the frontalis muscle stretched as well as providing a mechanical advantage that assists the muscle in supporting the brows and maintain their position. In some patients with forehead volume loss, upper lid droop (ptosis) and excess skin, a compensatory increase in frontalis muscle activity (hypertonicity) is believed to occur in an attempt to prevent obstruction of the visual fields. Increased muscle activity, in turn, can result in an increase in horizontal forehead wrinkles due to the contracture of the overlying skin.

Often older patients who develop wrinkles due to compensatory frontalis hypertonicity will seek BOTOX^®️ to try and reduce the appearance of these wrinkles. However, this can result in a significant drop in the brows and upper eyelids in these patients. A preferred option is to replace lost volume underneath the muscle using a volumising hyaluronic acid filler that is injected just above the bone but under the muscle (sub-galeal plane). This treatment restores the support for the overlying soft tissue, resulting in a softening of the frontalis muscle activity (and hence wrinkles) while maintaining the brow and upper eyelid positions as far as possible. Reducing the appearance of wrinkles through indirect volume replacement (ie without directly filling the wrinkles themselves) is an example of a process called myomodulation, which is further discussed in Facial Harmonisation. Any residual static or imprinted wrinkles visible at rest can then be treated with direct injections of a more superficial dermal filler, or smaller doses of BOTOX^®️.

Females have a slightly concave temple area, whereas males tend to have flat or even slightly convex (fuller) temples with a wider upper face and forehead. In both men and women, age-related volume depletion can develop, leading to pronounced temple hollowing. Some individuals, however, may develop temporalis muscle hypertrophy, where the muscles in the temples become enlarged, resulting in a bulky or fuller temple appearance. Temporalis muscle hypertrophy occurs more often in males and is usually accompanied by jawline masseter muscle hypertrophy (see Jawline). The shape and volume of the temples determine the width of the upper third of the face. Consequently, a decrease or increase in temple volume can narrow or widen the upper face, respectively, thereby affecting overall facial shape and proportions. Thus, volume changes in the temples have important implications not only in the upper third of the face but also the face as a whole.

Treating the temple region also has an important role when performing aesthetic enhancement of other regions of the face. Performing a cheek augmentation, such as with cosmetic fillers, in patients with who also have temple volume loss may result in a suboptimal appearance. Specifically, the concavity of the temples may exaggerate any changes made to the appearance of the cheeks, resulting in an overly defined and unnatural looking cheek contour, particularly when this occurs in parallel with volume depletion and concavity of the subzygomatic region below the outer cheekbones. Indeed, the combination of both temple and subzygomatic area volume loss can contribute to a skeletonised or gaunt appearance of the upper and mid-face. Hence it is essential, therefore, in these patients to address volume loss in the temples and subzygomatic region in addition to treating the cheeks.

Other areas impacted by the temples are the eyebrows. As the tail of the eyebrow extends to the temple, loss of volume in the temples can also lead to reduced structural support for the outer brows, resulting in a drop and shortening of the eyebrows. It is important, therefore to address volume depletion in the temple region when reshaping the brow as this can help to both lift and widen the eyebrow tail.

Treating the temples may also indirectly improve more distant areas of the face, including the tear troughs. This indirect correction occurs because of a myomodulatory effect on the orbicularus oculi muscle (OOM), which is a circular sphincter muscle whose action is to constrict to close the upper and lower eyelids, which also pulls the outer eyebrows down.

Hypertonicity of the OOM at rest can compress the eyelids closer to the globe of the eye, causing a deepening of tear troughs and hollows, as well as lowering the eyebrows and increasing wrinkles around the eye.

The outer part of the circular OOM extends anatomically to the temple area, where there is often volume loss with age. By replacing lost volume in the temples, the OOM becomes more expanded, which reduces the muscle tension at rest without affecting its ability to close the eyes themselves. In doing so, the tear troughs and hollows are therefore also slightly softened, with the additional benefit of elevating the tail of the brows and slightly reducing the wrinkles around the eyes. Although this effect is subtle, it is nevertheless beneficial as it allows less filler to be directly injected into the tear trough itself.    

Although an ‘ideal’ brow shape has been described there are significant variations of this that are each better suited to different individuals. Generally, youthful female eyebrows display a classic arch shape. Medially the brows start at the level of the superior orbital rim, arches to its superior point at the lateral limbus (outer border of the pupil), ending at a point tangent to the nasal ala and lateral canthus. In some females, a more accentuated arch is aesthetically optimal whereas in others a more subtle arch shape is better suited to that individual’s facial features. Consequently, a ‘one size fits all’ approach is not an appropriate method for determining aesthetic ideals and rather careful consideration should be given to overall facial shape and proportions. The preference in males is to have heavier and flatter eyebrows that are also positioned more inferiorly, which creates a more masculine appearance. Conversely, an exaggerated eyebrow arch or an eyebrow that is positioned too high can feminise a male face, particularly if it is also thin.

The actual eyebrow position and shape is determined by the dynamic balance of three opposing muscle groups (frontalis, corrugator supercilli and orbicularis oculi). Unlike other areas of the face, the overall soft tissue volume appears to remain relatively constant during the ageing process. Nevertheless, the ratio of muscle to fat that comprises this volume does seem to change with a decrease in muscle volume and an increase in fat content as we get older. However, there is a gradual reabsorption of the underlying bone as well as a loss of volume in the other surrounding fat compartments. These changes result in the widening of the eye socket and flattening of the lower forehead giving the impression that the brows have lost their fullness or become deflated with time.

The position and shape of the brow during ageing does vary significantly. In some individuals, the brows begin to descend with flattening of the youthful arch shape.  In others, the eyebrows start to elevate developing an excessive arch shape or upward slant (commonly referred to as “Spock-like” or “Spocking”) due to increased pull of the frontalis muscles. A subgroup of individuals develop a downward slanting eyebrow where the head of the inner eyebrow becomes more elevated while the outer body and tail start to drop. These different eyebrow patterns reflect variations in regional anatomy, including the shape of the underlying facial skeletal and muscles, as well as fat volume and ligaments. 

A combination of cosmetic fillers and BOTOX^®️ can be used to reposition and reshape the eyebrows depending on the anatomical placement of the products and the techniques used, helping to restore a more youthful appearance. This is achieved by treating the brows, forehead and temples in combination as each of those areas affect the brow shape and position differently. Using these more advanced techniques, the eyebrows can be made to look longer, more slanted, less slanted, more arched or flatter. Often these procedures are combined with additional treatments to the upper eyelid as part of an overall eye area rejuvenation including the correction of an A-frame deformity resulting from infrabrow hollowing.