Steiner S line: analysis of the lip profile
- Nerve
- Highlighted area
Quick facts
- Definition
- Profile line connecting the soft tissue pogonion to the midpoint of the S formed between the columella and the upper lip.
- Classic reference
- In a balanced profile, the lips touch the line or sit very close to it.
- Lips in front
- Suggest a protrusive lip profile.
- Lips behind
- Suggest a retruded or flat lip profile.
- Difference from the E line
- Uses the base of the nose, not the tip, so it is less influenced by nose size.
- Relevance in orofacial harmonization (HOF)
- Helps decide whether the lips and chin are in balance before adding volume.
The Steiner S line is a profile line connecting the soft tissue pogonion, the most anterior point of the chin, to the midpoint of the S-shaped curve formed between the columella and the upper lip. In the classic reference, the upper and lower lips touch this line or sit very close to it. It is one of the tools used in facial profile analysis to read lip position in relation to the nose and chin.
How to draw and read the S line
Measurement is done on a standardized profile photo, with the head in a natural position and the lips relaxed, without pressing one against the other.
| Lip position | Usual reading | Hypotheses to consider |
|---|---|---|
| Touching the line | Balanced lip profile by the classic reference | Assess other parameters before changing anything |
| In front of the line | Protrusive lips | Tooth projection, projected maxilla, recessed chin, full lips |
| Behind the line | Retruded lips or flat profile | Thin lips, retroclined teeth, projected chin or nose |
References vary with age, sex, and ethnic origin. Profiles of African and Asian origin, for example, tend to have lips further in front of the line without that representing an imbalance. For this reason the line is a reading guide, not a goal to be reached.
How does it compare with other profile lines?
| Line | Points | Classic lip reference |
|---|---|---|
| Steiner S | Soft tissue pogonion and base of the nose (middle of the columella S) | Touching the line |
| Ricketts E (Ricketts line) | Soft tissue pogonion and tip of the nose | Slightly behind, the lower closer than the upper |
| Holdaway H (Holdaway H line) | Soft tissue pogonion and upper lip | Assesses the lower lip and the angle with the profile |
The Steiner line is less influenced by the size and projection of the nose, which helps when the nose is very large or very small and distorts the reading of the E line.
Why does it matter in orofacial harmonization (HOF)?
- Lip filler: lips that already touch or go past the line have less room for volume without accentuating projection in profile. The topic is covered in lip filler.
- Chin: a recessed chin pulls the line back and makes the lips look more projected. In many cases, assessing the chin before the lips changes the plan, as described in retrognathic profile: assessment.
- Overall profile: the line is read together with the facial convexity angle and the nasolabial angle.
How does it show up in the assessment?
- Profile photo with relaxed lips and teeth in occlusion.
- Examination of the teeth: the inclination of the incisors changes lip position.
- Comparison with the mentolabial angle and the sulcus below the lower lip.
Also called: S line, Steiner line, S-line.
Frequently asked questions
How is the Steiner S line drawn?
On a profile photo, you connect the soft tissue pogonion, the most anterior point of the chin, to the midpoint of the S-shaped curve formed between the columella and the upper lip, just below the nose. Then you observe the position of the upper and lower lips in relation to that line.
What is the difference between the Steiner line and the Ricketts line?
The Ricketts E line runs from the tip of the nose to the chin, and the reference is to have the lips slightly behind it. The Steiner S line runs from the base of the nose to the chin, and the reference is for the lips to touch the line. Because it uses the base of the nose, the Steiner line changes less with large or small noses.