Facial midline: the symmetry reference
- Nerve
- Highlighted area
Quick facts
- Definition
- Imaginary vertical line that divides the face into right and left sides, seen from the front.
- Reference points
- Center of the hairline, glabella, nasion, tip of the nose, center of the philtrum, center of the lip, and chin.
- How to draw it
- Perpendicular to the line between the pupils, passing through the center of the glabella, on a standardized frontal photo.
- Dental midline
- Line between the upper central incisors, compared against the facial midline.
- Relevance in orofacial harmonization (HOF)
- Basis for reading asymmetry before any procedure.
The facial midline is an imaginary vertical line that divides the face, seen from the front, into right and left sides. It is usually drawn perpendicular to the line between the pupils, passing through the center of the glabella, and crosses references such as the tip of the nose, the center of the philtrum, the center of the lip, and the chin. In HOF, it is the starting point for reading facial asymmetry.
Which points does the midline cross?
| Point | Area | What a deviation may indicate |
|---|---|---|
| Center of the hairline | Upper third | Not very reliable: varies with the hair |
| Glabella and nasion | Between the eyebrows | Most stable reference for drawing the line |
| Tip of the nose and columella | Middle third | Deviation of the septum or the tip |
| Center of the philtrum and Cupid's bow | Upper lip | Lip or smile asymmetry |
| Upper dental midline | Teeth | Dental or arch deviation |
| Chin (pogonion) | Lower third | Deviation of the chin or jaw |
Because no face is perfectly symmetrical, the midline rarely passes through all points at once. Its value lies in showing where the deviation is and whether it is concentrated in one third of the face.
How to use it in the assessment
- Standardized frontal photo: head without rotation or tilt, gaze on the horizon, even light on both sides. Even a small rotation creates a false asymmetry. The method is covered in standardized clinical photography.
- Draw from stable points: the pupils and glabella are usually more reliable references than the hair or the chin.
- Compare at rest and in motion: a smile can shift the lip and chin to one side.
- Add the horizontal analysis: the rule of fifths and the division into thirds complete the proportion reading.
Why does it matter in orofacial harmonization (HOF)?
- Planning by side: in bilateral areas, deviations may call for different volumes on each side, a decision for the qualified professional after assessment.
- Lips: asymmetry of the Cupid's bow or the vermilion often becomes evident when the line is drawn. The topic is covered in asymmetric lips: assessment.
- Chin and nose: skeletal deviations of the chin or septum are not fully corrected with injectables and call for a frank conversation about the limits of the procedure.
- Documentation: recording the asymmetry before the procedure prevents the patient from attributing it to the treatment later.
Also called: midline of the face, median sagittal plane, axis of facial symmetry.
Frequently asked questions
What is the midline of the face?
It is an imaginary vertical line that passes through the center of the forehead, glabella, nose, philtrum, and chin, dividing the face into two sides. It serves as a reference for comparing the sides and noticing deviations.
Is every face asymmetrical?
Yes, to some degree. Small differences between the sides are normal and part of a natural face. The midline helps separate this common asymmetry from deviations that bother the patient or change the plan.