What is the nasolabial fold ? Anatomical definition
Anatomically, the nasolabial fold is a natural line at the junction between cheek and upper lip. It separates two distinct aesthetic areas : the middle third of the face, dominated by cheekbones and malar fat compartments, and the perioral region, involved in speaking, eating and expressing emotions.
This line is accentuated by contour differences between superficial tissues, which are more mobile and rich in fat, and deeper tissues, which are more fixed because they are anchored directly to bone. The nasolabial fold therefore exists in everyone at every age, but its depth varies considerably. It remains subtle in children, becomes more perceptible in young adults and gradually deepens over time.
Where is the nasolabial fold situated on the face ?
The nasolabial fold is a clearly visible anatomical line on each side of the face. It starts at the side of the nose and descends obliquely towards the outer angle of the upper lip at the lip corner. This natural line marks the boundary between two major aesthetic areas : the cheek, with its volume and mobility, and the perioral region, involved in speaking, eating and expressing emotions.
Although present in everyone from early life, its appearance changes over time. In children and young adults, it generally remains subtle and appears only when smiling. With age, gradual loss of skin tone, fat volume loss and tissue descent deepen it. The nasolabial fold then becomes permanent, sometimes giving a tired or harsh appearance even at rest.
Its location therefore makes it an essential landmark in facial ageing analysis. Understanding precisely where the nasolabial fold lies and how it changes helps interpret signs of age and propose appropriate, natural aesthetic solutions.
What role does the nasolabial fold play in facial expressions ?
The nasolabial fold plays an active role in facial dynamics and emotional expression. It forms and strengthens during contraction of several perioral muscles, particularly the levator labii superioris, zygomaticus major and, to a lesser extent, orbicularis oris. These muscles contribute to smiling, laughing, speaking and certain reflex expressions.
The nasolabial fold is therefore not solely static, but also a dynamic contour directly associated with facial animation. Daily repetition of these expressions, combined with gradual skin elasticity loss, eventually fixes this fold in the dermis, making it visible even at rest.
What is the difference between a nasolabial fold, a wrinkle and a skin fold ?
The nasolabial fold should not be confused with a simple wrinkle. An expression wrinkle is a superficial dermal crease associated with repeated muscle movements, such as forehead or glabellar lines. The nasolabial fold, however, is an often deep structural fold rooted in facial anatomy and accentuated by volume loss and gravity.
It also differs from a functional skin fold, which disappears when the face is at rest. When pronounced, the fold persists regardless of expression. It then becomes a permanent facial feature, often associated — sometimes wrongly — with an impression of fatigue, severity or ageing.
How does the nasolabial fold develop ?
The nasolabial fold relies on complex deep architecture comprising the maxillary bone, facial support ligaments and superficial and deep fat compartments. The maxillary bone's degree of projection partly determines cheek convexity and, by contrast, fold prominence. Limited projection of this bone, called maxillary hypoplasia, can therefore make the fold visible very early, sometimes from childhood.
Skin ligaments, particularly the nasolabial ligament, anchor soft tissues to deep structures. Over time, their suspensory capacity declines, causing gradual tissue laxity that accentuates fold depth.
Finally, volume loss in fat pads, particularly the deep malar region, contributes to these changes. By altering the tensions holding tissues in place, it deepens the nasolabial fold further.
Why is the nasolabial fold a sign of ageing ?
In clinical practice, the nasolabial fold is among the first visible signs of facial ageing. Its development generally follows a fairly regular sequence : initially subtle and perceptible only when smiling, it gradually becomes marked at rest and then is accompanied by secondary wrinkles such as marionette lines or cheek folds.
This transformation reflects more than volume loss. It also reflects gradually declining skin quality — becoming thinner, drier and less toned — and weakening of deep support structures. The nasolabial fold should therefore be considered part of an overall process of facial tissue laxity and disorganisation rather than an isolated phenomenon.
Why do some people have a more pronounced nasolabial fold ?
Nasolabial fold severity varies considerably between individuals. This depends on several factors, including genetics, bone structure, skin quality and certain lifestyle habits. Repeated expressions, thin skin, limited cheekbone projection or a broad smile therefore encourage earlier fold deepening.
Environmental and behavioural factors add to these predispositions. Repeated sun exposure, smoking, substantial weight fluctuations or hormonal imbalances accelerate collagen breakdown and reduce skin resistance to mechanical tension. They are not the direct cause, but aggravate and hasten fold formation.
Why does the nasolabial fold create a tired appearance ?
In collective perception, the nasolabial fold carries strong expressive significance. When it deepens, it is spontaneously associated with tiredness, persistent sadness or even severity that does not necessarily reflect the person's state of mind. This mismatch arises from how light and shadows fall on the face : the fold creates a clear break in feature continuity, suggesting a less open, less rested face.
Beyond its purely anatomical aspect, the nasolabial fold therefore becomes a true element of non-verbal communication. It influences others' perception of the face and the image each person projects socially or professionally. This perceptual dimension explains precisely why many patients experience the fold as unattractive as soon as it becomes visible, regardless of their actual age or vitality.
How can early signs of the nasolabial fold be recognised ?
The nasolabial fold first appears as a simple temporary shadow visible during facial movements, particularly smiling. At this stage, the fold is not permanent and disappears at rest. Gradually, as skin loses tone, malar volume shifts and skin thickness decreases, this shadow becomes a deeper line visible even without expression. This is then called a fold at rest. In some patients, slight adjacent tissue sagging or loss of cheekbone fullness may precede its appearance. Careful examination in natural light, combined with gentle palpation, detects the first signs of deepening, sometimes before patients notice them.
