The e line face measurement is the signed perpendicular distance from a lip point L to the line from pronasale Prn to soft-tissue pogonion Pog′. Formula: d = ((xPog′ − xPrn)(yL − yPrn) − (yPog′ − yPrn)(xL − xPrn)) / √((xPog′ − xPrn)² + (yPog′ − yPrn)²). It’s a raw distance, not a ratio or angle. Measure L at labrale superius for the upper lip and labrale inferius for the lower lip.
Prn is the most forward point of the nose tip in profile. Pog′ is the most forward point on the soft-tissue chin. Labrale superius and labrale inferius are the most forward midline points on the upper and lower lips. Ricketts described this nose-to-chin reference, also called the esthetic plane or E-plane, in 1968.
This guide uses the shortest distance at right angles to the line. Some methods use a horizontal offset instead. Other profile lines use the columella, subnasale or upper lip as an endpoint. Those conventions give different numbers. So do opposite sign rules. The formula’s sign depends on image direction. Here, relabel it so positive means toward the side the face points and negative means behind the line.
How to draw the Ricketts E-line on a photo
- Take a true side view. Keep your head in a relaxed, natural position. Look straight ahead. Let your lips rest without pursing or forcing them closed.
- Step back from the camera. Avoid an arm’s-length, wide-angle selfie. Keep the camera around midface height, then use modest zoom to frame the head.
- Mark the four points. Place Prn on the visible nose tip, Pog′ on the visible chin tip, Ls on the upper lip and Li on the lower lip.
- Join Prn and Pog′. That straight segment is the E-line. Drop a perpendicular from Ls and another from Li.
- Record the setup. Save the original photo, point locations, pixel distances and sign rule. A millimetre reading needs a known scale in the same plane as the profile.
Photo setup matters. Fernández-Riveiro and colleagues used standardized profile photographs in natural head position for their 2002 photogrammetric study. Amuk, Topsakal and Baser Keklikci tested four head-position methods in 45 people in 2019. Several visible facial projections changed with the positioning method, including the nose tip, lips and chin.
Camera distance matters too. Třebický and colleagues photographed the same 45 people at 50, 85 and 105 mm full-frame-equivalent settings in a 2016 PLOS ONE study. They changed camera distance to keep head size similar. Measured facial shape still differed across the images. The study didn’t test the E-line itself. It shows why repeat photos need the same device, zoom, distance, height and head position.
Illustrative example: calculate both lip distances
Imagine a synthetic profile facing right. Prn is at (100, 40) pixels and Pog′ at (100, 200). The E-line is therefore x = 100. Ls sits at (94, 105), while Li sits at (96, 130). The upper lip is 6 px behind the line. The lower lip is 4 px behind it.
These are pixel distances. They aren’t millimetres. If an illustrative same-plane scale showed 10 px per 1 mm, the readings would convert to 0.6 mm and 0.4 mm. A normal phone photo has no trustworthy scale by default. Cropping or resizing also changes the pixel count.
Now move only the marked nose point 3 px, from (100, 40) to (103, 40). Keep every other point fixed. The calculated upper-lip distance becomes about 7.8 px instead of 6 px. Nothing about the synthetic lip changed. A small landmark error changed the reading by about 30%.
Rotating the finished image alone won’t change a perpendicular distance. Tilting the head before capture is different. It changes the three-dimensional projection and may change which skin point looks most prominent.
Why the line can move without the lips moving
| Change | What happens to the reading | What you can conclude |
|---|---|---|
| The nose tip appears more projected | Prn moves forward, rotating the line away from the lips. | The lips may read farther behind. This doesn’t prove they are thin or retruded. |
| The soft-tissue chin appears more projected | Pog′ moves forward, shifting the lower end of the line. | Both lip distances can change. The photo doesn’t isolate jaw bone or bite. |
| A lip looks fuller, pursed or relaxed | Ls or Li moves while the two line endpoints may stay fixed. | The reading describes that moment’s lip posture, not a stable trait by itself. |
| A beard or shadow hides the chin edge | Pog′ becomes harder to place consistently. | Marking uncertainty may dominate the result. Don’t treat a guessed point as precise. |
| Head position, camera distance or zoom changes | The visible projections and landmark positions can shift together. | Compare matched photos only. A mismatch is a retake signal, not a facial change. |
This is why the E-line is relational. A reading combines nose projection, soft-tissue chin projection and lip position. It doesn’t measure any one feature alone. A larger-looking nose changes the line only if its visible tip moves. Nose width and height aren’t in the formula. Jaw structure and lip volume need separate observations.
There is no universal ideal E-line value
A historical reference value isn’t a beauty rule. It comes from a particular method and sample. Alcalde and colleagues analyzed cephalograms from 211 Japanese adults in 2000. Their measurements differed from white reference data, and the authors warned that group norms shouldn’t become treatment goals.
Age can also move both endpoints. Buschang, Fretty and Campbell studied 79 growing patients in 2011. Changes measured against five profile lines, including the E-line, correlated weakly with actual lower-lip movement. For the E-line, changing nose and chin references could even make the apparent direction misleading. That finding concerns change over time; it doesn’t erase the line’s descriptive use in one controlled image.
A photo measurement is not a skeletal or clinical measurement. It can show where visible soft-tissue points fall in one projection. It cannot establish bone position, dental relationships, breathing function or a need for treatment. It also cannot turn a population average into a personal target.
How to use the E-line for grooming
Use it as a profile-framing note, not a styling command. Face shape and the E-line answer different questions. The E-line concerns four points in a side view. Face shape describes the visible outline, mainly from the front. The guide to face shape versus facial proportions separates those jobs.
- Hair: Volume near the crown, sides or jaw can change profile framing. The E-line cannot select a haircut by itself.
- Brows and glasses: These sit around the eyes and upper face. Front and three-quarter views usually matter more. Use frame width, brow line and cheek contact as separate checks in the glasses and face-shape guide.
- Beard: A beard can change the apparent chin edge and make Pog′ harder to mark. If you want to test that framing, compare the options in the beard-style guide.
- Makeup: Lip colour, liner placement and light on the nose or chin can change perceived balance in a photo. They don’t change the underlying E-line measurement unless the visible landmark itself is redrawn or obscured.
None of these options is required. The useful question is whether a styling change creates the framing you want across matched front, profile and three-quarter photos.
Choose the next check that matches your question
If your next question is face shape rather than profile projection, try the free on-device face-shape finder. It estimates the visible outline from a front photo without an account or email. It doesn’t measure the E-line or reveal bone anatomy.
Oscar Nascimento
Editorial writer, GlowUp Face
Oscar writes about evidence-based skin care, healthcare, looksmaxxing, and the social and economic research surrounding appearance.
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