Subnasale-pogonion line: lip profile reference

The subnasale-pogonion line is, as the name says, the straight line between the subnasale point (where the base of the nose meets the upper lip) and the soft tissue pogonion (the most anterior point of the chin). In many descriptions it is the same reference called the Burstone line; other sources use the descriptive name to avoid ambiguity.

What does it show in profile?

With the line drawn, you observe both lips in relation to it. Lips well in front suggest lip protrusion or a recessed chin; lips well behind may indicate retrusion or thin lips. The reading is visual: it invites the professional to ask where the imbalance comes from before deciding where to treat.

The key point is the pogonion. If the chin is under-projected, the line becomes "tilted" and the lips appear forward. In that case, working on the chin can restore balance without enlarging the lip. For more context, see retrogenia.

How to combine it with other readings

No single profile line tells the whole story. It is worth cross-checking with:

• the mentolabial angle, which describes the curve between the lower lip and the chin;
• the lip proportion between the upper and lower lip;
• the Steiner S line and the Ricketts line, when the practice uses them;
• the facial profile as a whole, including the nose and forehead.

Practical precautions for the photo

Distortion in the profile photo changes the reading more than it seems. A few rules help:

• constant camera distance, without getting too close;
• head level, without raising or lowering the chin;
• lips relaxed, without pursing or pressing them;
• same background and lighting in follow-up photos.

In Harmy

The app uses a single frontal photo and does not analyze the profile. The Lips and Chin points simulate, from the front, the marked area with the volume in ml entered, as an illustrative simulation. Profile reading is done by the professional with their own photos and exam.

Also called: lip profile line, soft tissue profile reference line.