Lips and mouth

Lip morphology, perioral anatomy, and visible oral structures (teeth, tongue when in frame). Absorbs the original Lips, Mouth, and Tongue atlas categories per the granularity decision. Dimensions are drawn from craniofacial anthropometry (Farkas), aesthetic-medicine literature (Mallucci, Powell-Humphreys), and orofacial-anatomy references. Lip volume varies dramatically across ethnic groups; the contemporary aesthetic-medicine literature provides the relevant categorical frameworks.

Dimensions

• Overall lip volume

  photo-observable

  ordinal · lip_volume_qualitative

  Combined lip volume from a frontal view. Independent ethnic-correlated dimension; West African and African-diaspora populations average higher native lip volume than European populations, with substantial individual variation.

  Aligned with the Mallucci-Branford 1:2 upper-to-lower aesthetic ratio framework and contemporary lip-augmentation literature.

  Valid values (4)

  • thinThin— Minimal lip volume; lips barely project from the perioral plane.
  • moderateModerate— Average volume; lips clearly visible with modest projection.
  • fullFull— Pronounced volume; lips project substantially from the perioral plane.
  • very_fullVery full— Very pronounced volume — either constitutional or augmented.

• Upper-to-lower lip volume ratio

  photo-observable

  categorical · mallucci_branford_lip_ratio

  Relative volume of the upper lip compared to the lower lip in frontal view.

  Mallucci P, Branford OA (2012). Aesthetic Plastic Surgery. The 1:1.6 (upper:lower) ratio identified as the perceived-natural reference; deviations captured here as ratio buckets.

  Valid values (4)

  • upper_dominantUpper dominant— Upper lip larger than lower; uncommon. Often a sign of cosmetic over-augmentation.
  • balancedBalanced (~1:1)— Upper and lower lip of approximately equal volume.
  • lower_dominant_naturalLower dominant (natural ratio)— Lower lip larger than upper, approximating the 1:1.6 aesthetic reference.
  • lower_dominant_pronouncedLower dominant (pronounced)— Lower lip substantially larger than upper, beyond the natural reference.

• Cupid's bow morphology

  photo-observable

  categorical · cupids_bow_qualitative

  Shape of the upper-lip vermilion border at midline (Cupid's bow).

  Aesthetic-medicine descriptors aligned with the Niamtu lip-anatomy literature.

  Valid values (4)

  • sharp_definedSharp / defined— Crisp angular peaks at the philtral columns; clear M-shape.
  • softSoft / rounded— Gentle curves at the peaks; M-shape present but rounded.
  • flatFlat— Minimal definition; vermilion border nearly straight at midline.
  • asymmetricAsymmetric— Notable left-right peak asymmetry.

• Philtrum definition

  photo-observable

  categorical · philtrum_qualitative

  Shape and definition of the philtrum (the vertical groove between the nose and upper lip).

  Farkas LG (1994). Anthropometry of the Head and Face, 2nd Edition.

  Valid values (5)

  • defined_columnsDefined columns— Clear philtral columns visible; well-demarcated central groove.
  • softSoft— Subtle column definition.
  • smooth_minimalSmooth / minimal— Philtrum nearly flat; columns not distinct.
  • elongatedElongated (long upper lip)— Vertical philtrum length above the aesthetic reference range.
  • shortShort upper lip— Vertical philtrum length below the aesthetic reference range.

• Mouth width

  photo-observable

  ordinal · mouth_width_proportional

  Width of the mouth (cheilion to cheilion) relative to the inter-iris distance.

  Farkas LG (1994). Reference: mouth width approximately equal to the distance between the medial limbus of each iris.

  Valid values (3)

  • narrowNarrow— Mouth width substantially less than inter-iris distance.
  • balancedBalanced— Mouth width approximately equal to inter-iris distance (Farkas reference).
  • wideWide— Mouth width substantially greater than inter-iris distance.

• Lip corner orientation

  photo-observable

  categorical · oral_commissure_orientation

  Resting orientation of the oral commissures.

  Aligned with descriptors used in facial-aging literature and aesthetic-medicine commissure-correction context.

  Valid values (3)

  • upturnedUpturned— Corners angle upward at rest; impression of a slight smile.
  • neutralNeutral— Corners horizontal at rest.
  • downturnedDownturned— Corners angle downward at rest; impression of resting frown ('marionette' appearance with aging).

• Vermilion border definition

  partly photo-observable

  ordinal · vermilion_border_qualitative

  Sharpness of the vermilion-cutaneous junction.

  Aesthetic-medicine descriptor aligned with lip-augmentation pre-procedure assessment.

  Valid values (3)

  • sharp_definedSharp— Crisp boundary between vermilion and surrounding skin.
  • softSoft— Gradual transition; vermilion edge visible but not sharp.
  • indistinctIndistinct— Vermilion border barely discernible; common with lip-aging.

• Dental visibility (smile)

  photo-observable

  categorical · smile_classification_visibility

  Visibility of teeth and gingiva in the photographed expression.

  Aligned with orthodontic / smile-aesthetics literature: Liébart MF et al. (2004). Smile line and periodontium visibility. Periodontal Practice Today, 1(1).

  Valid values (5)

  • coveredCovered (lips closed)— Teeth not visible; mouth closed.
  • minimal_showMinimal show— Slight tooth visibility (e.g. resting parted lips).
  • low_smile_lineLow smile line— Smile shows less than 75% of upper anterior teeth.
  • average_smile_lineAverage smile line— Smile shows 75-100% of upper anterior teeth without gingival show.
  • high_smile_lineHigh smile line / gummy smile— Smile shows full upper teeth plus a band of gingiva ('gummy smile').

• Dental alignment (when visible)

  photo-observable

  categorical · dental_alignment_qualitative

  Alignment of visible anterior teeth when teeth are in frame.

  Aligned with orthodontic descriptors of anterior dental alignment; Angle classification is occlusion-based and not photo-assessable.

  Valid values (7)

  • alignedAligned— Anterior teeth straight, evenly spaced.
  • mild_irregularityMild irregularity— Subtle crowding or rotation visible.
  • crowdedCrowded— Pronounced crowding; teeth overlap or rotate substantially.
  • spaced_diastemaSpaced / diastema— Visible gap(s) between anterior teeth; central diastema is the most common.
  • missing_teeth_visibleMissing teeth visible
  • orthodontia_visibleOrthodontia visible (braces / retainer)— Active or recent orthodontic appliance visible; native alignment not directly observable.
  • not_visibleNot visible— Teeth not in frame; alignment cannot be assessed.

• Tongue morphology (when visible)

  rarely from photo

  categorical · tongue_qualitative

  Morphology of the tongue when in frame. Most photographs do not show the tongue; this dimension is included for schema completeness and rare cases where the tongue is visible (e.g. tongue-out expressions).

  Aligned with descriptors used in the orofacial-anatomy literature; mostly observable in extended-tongue photographs.

  Valid values (5)

  • not_visibleNot visible
  • normalNormal
  • geographic_tongueGeographic tongue (visible patches)
  • fissured_tongueFissured tongue
  • long_anteriorlyLong / anteriorly extending