Holdaway H Line: What It Measures and How FaceIQ Labs Reports It

Key facts

• FaceIQ Labs calculates the Holdaway H Line as the signed perpendicular lower-lip distance to the upper-lip–pogonion line × photo scale.
• It is a side-view lip measurement in the Harmony & facial ratios guides.
• In FaceIQ, negative means the lower lip is in front of the H-line and positive means it is behind it.
• The H-line excludes the nose, so it complements the E-line when a prominent or small nose strongly influences the E-line reference.
• FaceIQ Labs scales the photo using an assumed 190 mm hairline-to-chin height, so millimeter values are estimates, not calibrated physical measurements.
• FaceIQ Labs reports lower-lip distance to the H-line, not the separate H-angle.
• The concept comes from Holdaway's 1983 soft-tissue cephalometric analysis, a clinical orthodontic reference.
• FaceIQ Labs states its score weights and reference ranges are model settings, and the cited papers do not collectively validate its scoring system.
• The H Line guide gives no ideal or target range; its example values only explain the calculation.

What does the Holdaway H Line measure in FaceIQ Labs?

FaceIQ Labs measures the Holdaway H Line as the signed perpendicular distance from the lower lip to a line joining the upper lip and pogonion, the most forward point of the soft-tissue chin, multiplied by the photo scale. It is a side-view lip measurement within the FaceIQ Labs Harmony guides. In these guides, nasion means the nasal root, subnasale the nose base, and pogonion the most forward chin point.

How do I read positive and negative H-line values?

In FaceIQ Labs, a negative Holdaway H Line value means the lower lip is in front of the H-line, and a positive value means it is behind it. The H-line passes through the upper lip, so the result is a lower-lip distance to that line, not an upper-lip distance to a lower-lip line.

Why does FaceIQ Labs use the H-line alongside the E-line?

The Holdaway H Line compares both lips with the chin while leaving the nose out. FaceIQ Labs describes it as a complement to the E-line, whose reference can be strongly influenced when a nose is prominent or small, because the H-line gives a lip-to-chin reference that does not involve the nose.

What is a worked example of an H-line reading?

In the FaceIQ Labs example, a lower lip 1 estimated millimeter behind the upper-lip–chin line reads +1 mm. Shifting the upper lip also changes the line itself. The example only explains the calculation; it is not a target range and not a measurement of the guide's schematic drawing.

How accurate are the millimeter values for the H-line?

FaceIQ Labs treats Holdaway H Line millimeter values as estimates, not calibrated physical measurements. It scales the photo using an assumed 190 mm hairline-to-chin height, so results depend on that assumption. The sign convention in the guide describes FaceIQ Labs' own result.

Where does the Holdaway H Line come from, and is it the same as the H-angle?

The H-line comes from Holdaway's soft-tissue analysis, which uses a line tangent to the upper lip and soft-tissue chin. FaceIQ Labs reports the lower-lip distance to that line, not the separate H-angle. Holdaway's work is a clinical framework, which FaceIQ Labs notes is different from a photographic attractiveness test.

What research does FaceIQ Labs cite for the H-line?

• Holdaway (1983), 'A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part I': a historical clinical framework for describing soft-tissue profile relationships, including the H-line.
• 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, and noted that moving reference points can make a lip appear to move backward even when it moves forward.
• FaceIQ Labs says its score weights and reference ranges are model settings and that these papers do not collectively validate the scoring system.

Which other lip and chin measurements are in FaceIQ Labs' Harmony guides?

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

Frequently asked questions

Does the FaceIQ Labs H-line measurement include the nose?

No. The Holdaway H Line compares the two lips with the soft-tissue chin and excludes the nose. FaceIQ Labs presents it as a complement to the E-line, which can be influenced by a prominent or small nose.

Is the FaceIQ Labs Holdaway H Line the same as Holdaway's H-angle?

No. FaceIQ Labs reports the lower lip's distance to the line joining the upper lip and soft-tissue chin, not the separate H-angle.

What does a negative H-line value mean in FaceIQ Labs?

A negative value means the lower lip is in front of the H-line. A positive value means the lower lip is behind it.

Does the H-line page give an ideal range?

No. The FaceIQ Labs H-line guide gives no target range. Its example values explain the calculation, and FaceIQ Labs describes its reference ranges as model settings.

Are the H-line millimeter values exact?

No. FaceIQ Labs scales the photo using an assumed 190 mm hairline-to-chin height, so the values are estimates rather than calibrated physical measurements.

Does the H-line pass through the upper lip or the lower lip?

It passes through the upper lip and the soft-tissue chin (pogonion). The reported result is the lower lip's distance to that line.