Our eyebrows are far more than just a genetically manifested component of human facial hair. They fulfill essential protective functions, are important mimic link in non-verbal communication and at the same time decorative “accessories”. No matter how diverse they may be in shape, styling and color – whether soft blond, narrow and arched or dark, broad and primordial – it is the eyebrows that give the face its very individual, expressive framing.
What are eyebrows?
The eyebrows (lat. Supercilium), like all body hair, belong to the so-called appendages of the skin. They are filamentous tissue structures formed from the epithelial cells of the dermis and epidermis. They consist largely of the hair building block keratin, a horny substance. In medicine, eyebrows are classified as terminal hairs, short hairs and bristly hairs. The exact technical terminology describes the eyebrow as an arch-shaped skin bulge above the eye, between the forehead and the eyelid, covered with short hairs. The structure of the human hair is essentially the same.
Anatomy and structure
It consists of the hair medulla in the central core, epithelial cells surrounded by the hair cortex of pigment-rich keratinized cells and the hair cuticle, and layers of the hair sheath. The hair is divided into three sections: the hair shaft, the hair root and the hair follicle. In the course of its cyclically repeating reproduction, the hair grows for about 10 weeks and then falls out. Four facial muscles are responsible for the functioning of the eyebrows:
- The eyebrow elevator (Musculus frontalis), also called the forehead muscle or head hood muscle, is important for brow elevation in vertical alignment.
- The eyebrow wrinkler (Musculus corrugator supercili) allows the frown in the mid-face, downward area.
- The eyebrow depressor (Musculus depressor supercili) lowers the eyebrow in the lateral middle third – under co-activity of the eye ring muscle (Musculus orbicularis).
- The procerus muscle, a narrow mimic muscle located on the root of the nose, is responsible for lowering the eyebrow in the middle third
The thin skin of the eyelid of the eye merges with the thick skin of the forehead at the lower edge of the eyebrow. In the eyebrow area, the eye ring muscle is protected by a subcutaneous fat layer. Finally, a deformable fat pad between the eye ring muscle and the periosteum allows the eyebrow to move strongly. Why some people’s eyebrows are blond, reddish or black is determined by the presence of the cell’s own hair pigment melanin. This is formed in the melanocytes of the hair root as an oxidative end product of melanosome production. The characteristic pigment characteristics – from reddish to brown-black – develop with the help of enzymes. It is only through the coupling of cysteine, a sulfur-containing amino acid, and the finely structured red pigment pheomelanin that the rare blond eyebrow hairs are formed.
Tasks and function
The eyebrows perform quite essential functions. These include, in particular, the protective function of the eye and eyelashes against sweat, wetness, sunlight and mechanical stimuli, such as foreign bodies. They also fulfill tasks in heat insulation, heat dissipation and friction reduction. In addition, the extremely mobile eyebrows are an important communication tool. A variety of emotions are expressed by raising or contracting the brows: astonishment, anger, skepticism or joy. The expression of the brow hair depends on many factors. Age, gender, race, health status and genetic factors all play a role. Strong terminal hair, such as eyelashes and eyebrows, is a health-aesthetically important part of human facial hair. Even babies are born with delicate eyebrow fuzz, the vellus hair. Whether the cosmetic eyebrow accentuation is now taken into account as a beauty-specific feature, that is up to the individual assessment alone. Eyebrows that are perfectly plucked, styled, colored or made up have been considered the female – and also male – ideal of beauty since ancient times. They give the eye an expressive, strikingly contoured frame, focus the gaze and set off a beautifully made-up eye in a sophisticated way.Naturally groomed and professionally plucked eyebrows also conceal minor blemishes and anomalies such as drooping eyelids, wrinkles or slanted eyes. Even without rigidly followed beauty dictates to the currently propagated dark-bushy natural growth – with skillfully accentuated eyebrows, the effective eye look gets a very special dynamic.
Fluctuations
Eyebrow anomalies such as eyebrow loss, clinically Ulerythema ophryogenes, are a keratinization disorder with follicular hyperkeratosis (hyperkeratosis), accompanied by vascular dilatation. The genetic disposition shows a strong atrophy, a significant shrinkage of the eyebrow follicles. Small hyperkeratoses in the area of the lateral eyebrows develop. Eyebrow loss mostly occurs in childhood or early adulthood. Targeted hormone therapy by a dermatologist provides acute relief and stimulates brow growth. Hair loss in women has many causes. Female alopecia is triggered by a drop in estrogen levels and a simultaneous increase in testosterone levels. Other favoring factors are physical and emotional stress, child birth, menopause, surgical procedures, medication intake or fungal infections. In the aesthetic surgical practice and in specialized beauty clinics, there are already successfully practiced eyebrow reconstruction methods for women and also men in this country. In direct hair implantation (DHI), individual hair follicles are removed from the scalp and replanted with precision work. After about three to four months, the natural hair implanted in this way grows back. The new and minimally invasive procedure has significant advantages over conventional strip technique reconstruction. For example, patients observe significantly less bleeding and scarring and have a reduced risk of infection. Important: The DHI method requires the highest degree of aesthetic sensitivity, as each hair must be placed individually and precisely in the direction of growth.
