Lower Lip E-Line Position: What FaceIQ Labs Measures and How to Read It

Key facts

• Calculation: perpendicular lower-lip distance to the E-line × photo scale.
• The E-line runs from the nose tip to the soft-tissue chin and is based on Ricketts' esthetic line, described in his 1968 work on lip relationships.
• FaceIQ sign convention: negative = lip in front of the line; positive = lip behind the line; zero = contact.
• FaceIQ scales photos using an assumed 190 mm hairline-to-chin height, so millimeter values are estimates, not calibrated physical measurements.
• A projecting nose can move the E-line forward and make the lips read farther behind it.
• FaceIQ's sign convention may be the reverse of a research paper's convention.
• This is a side-view, lips-region guide within the Harmony pillar of FaceIQ Labs.
• FaceIQ's score weights and reference ranges are model settings; the cited papers do not collectively validate the scoring system.
• The guide gives no target or ideal range; its example values only explain the calculation.

How does FaceIQ Labs calculate Lower Lip E-Line Position?

FaceIQ Labs calculates Lower Lip E-Line Position as the perpendicular distance from the lower lip to the E-line, a line from the nose tip to the soft-tissue chin, multiplied by the photo scale. It is a side-view Harmony measurement in the lips region, reported in estimated millimeters. In FaceIQ's guides, nasion means the nasal root, subnasale the nose base, and pogonion the most forward chin point. Frankfort refers to the direction from the ear-opening landmark to the lower orbital landmark.

What does a positive or negative Lower Lip E-Line value mean?

In FaceIQ Labs, a negative Lower Lip E-Line Position means the lower lip lies in front of the E-line, a positive value means it lies behind the line, and zero means the lip touches the line. FaceIQ's sign convention may be the reverse of the convention in some research papers, so check the convention before comparing values.

Why does FaceIQ Labs measure the lower lip against the E-line?

FaceIQ Labs measures Lower Lip E-Line Position to relate the lower lip to the nose–chin framework of the face. Reading it alongside FaceIQ's Upper Lip E-Line Position measurement helps distinguish how each of the two lips relates to the same reference line.

Where does the E-line concept come from?

The E-line in FaceIQ Labs' Lower Lip E-Line Position guide is Ricketts' esthetic line, which links the nose tip with the soft-tissue chin. It was developed as a clinical profile reference and is described in Ricketts' 1968 work on lip relationships, "Esthetics, environment, and the law of lip relation". The E-line depends on the nose and chin as well as the lips.

Can nose shape change a Lower Lip E-Line reading?

Yes. Because the E-line used by FaceIQ Labs starts at the nose tip, a projecting nose can move the line forward and make the lips read farther behind it. A 2011 study by Buschang, Fretty & Campbell, cited by FaceIQ, notes that moving reference points can make a lip appear to move backward even when it moves forward.

How exact are the millimeter values?

The millimeter values in FaceIQ Labs' Lower Lip E-Line Position are approximate. FaceIQ scales each photo using an assumed 190 mm hairline-to-chin height rather than a calibrated physical reference, so the figures are estimates, not calibrated physical measurements. The guide's sign convention describes FaceIQ's own result specifically.

What is a worked example of the Lower Lip E-Line calculation?

FaceIQ Labs gives this example: a lower lip 2 estimated mm behind the E-line reads +2 mm. Moving it onto the unchanged line gives zero, and placing it 1 mm in front gives −1 mm. These example values explain the calculation; they are not a target range and not measurements of the guide's schematic.

Is there an ideal range for Lower Lip E-Line Position?

FaceIQ Labs' Lower Lip E-Line Position guide does not give an ideal or target range. Its example values only explain the calculation. FaceIQ states that its score weights and reference ranges are model settings, and that the papers it cites do not collectively validate the scoring system.

What research does FaceIQ Labs cite for the Lower Lip E-Line?

FaceIQ Labs cites two papers for Lower Lip E-Line Position. Ricketts (1968) is the historical source for the esthetic-plane approach to lip relationships. Buschang, Fretty & Campbell (2011), "Can commonly used profile planes be used to evaluate changes in lower lip position?", compared five lip reference lines, including Steiner's S-line, in 79 orthodontic patients. FaceIQ says they explain history and related evidence rather than validate its scoring.

Which related lip measurements does FaceIQ Labs cover?

• Lower Lip S-Line Position
• Upper Lip S-Line Position
• Upper Lip E-Line Position
• Lower Lip Burstone Line
• Upper Lip Burstone Line
• Holdaway H Line
• Mentolabial Angle

Frequently asked questions

Is the Lower Lip E-Line Position exact, in real millimeters?

No. FaceIQ Labs scales each photo using an assumed 190 mm hairline-to-chin height, so the values are estimates, not calibrated physical measurements.

What does zero mean for Lower Lip E-Line Position?

Zero means the lower lip is in contact with the E-line, the line from the nose tip to the soft-tissue chin.

Is there an ideal range for Lower Lip E-Line Position?

The FaceIQ Labs guide does not give a target range. Its example values only explain the calculation, and FaceIQ says its reference ranges are model settings.

Does research validate FaceIQ Labs' E-line scoring?

No. FaceIQ states the cited papers explain the history and related evidence but do not collectively validate its score weights or reference ranges.

Why might my lips read behind the E-line?

A projecting nose can move the E-line forward, which makes lips read farther behind it without the lips themselves changing.

Does a negative value mean the same thing in every research paper?

Not necessarily. FaceIQ Labs notes its sign convention may be the reverse of a paper's convention, so check the convention before comparing values.