Feet

Foot morphology: foot size, arch height, toe length pattern, midfoot width, heel and ankle morphology, nail shape. The toe-length-pattern dimension (Greek / Egyptian / Roman / Square) is the canonical anthropometric foot-typology classification, dating to classical-art conventions and used in modern podiatry literature.

Dimensions

• Foot size (relative to body)

  partly photo-observable

  ordinal · foot_size_qualitative

  Foot length relative to body height.

  Aligned with anthropometric foot-length proportions (typical ratio ~14-15% of body height).

  Valid values (3)

  • smallSmall
  • averageAverage
  • largeLarge

• Arch height (medial longitudinal)

  partly photo-observable

  ordinal · arch_index_qualitative

  Height of the medial longitudinal arch when standing.

  Cavanagh PR, Rodgers MM (1987). The arch index: a useful measure from footprints. Journal of Biomechanics, 20(5): 547-551. Original quantitative scale; this dimension uses three qualitative buckets aligned with the clinical classification of high-arch / normal / flat-foot.

  Valid values (3)

  • flat_pes_planusFlat (pes planus)— Reduced or absent arch; medial border of foot rests near the floor.
  • normalNormal
  • high_pes_cavusHigh (pes cavus)— Pronounced arch; reduced foot-floor contact area.

• Toe length pattern

  photo-observable

  categorical · toe_typology_classical

  Relative length of the great toe (hallux) versus the second toe and remaining toes. Classical names derive from frequencies in art conventions; modern usage is descriptive.

  Classical anthropometric foot typology described in podiatry literature; Hawes MR, Sovak D, Miyashita M, Kang SJ, Yoshihuku Y, Tanaka S (1994). Ethnic differences in forefoot shape and the determination of shoe comfort. Ergonomics, 37(1).

  Valid values (5)

  • egyptianEgyptian— Hallux longest; toes decrease in length from first to fifth in a straight diagonal. Most common pattern globally.
  • greek_mortonGreek (Morton's)— Second toe longer than hallux; common variant. Sometimes associated with biomechanical foot-strike patterns.
  • roman_squareRoman / square— First three toes approximately equal in length, then sharp drop. Less common variant.
  • stretched_longStretched (long-toed)— All toes long relative to forefoot length.
  • asymmetricAsymmetric— Notable left-right toe-pattern asymmetry.

• Forefoot width

  photo-observable

  ordinal · forefoot_width_qualitative

  Width of the forefoot at the metatarsal heads relative to foot length.

  Aligned with shoe-fitting and ergonomics descriptors of forefoot breadth.

  Valid values (3)

  • narrowNarrow
  • averageAverage
  • wideWide— Broad metatarsal width; common variant in some populations.

• Heel morphology

  partly photo-observable

  categorical · heel_qualitative

  Soft-tissue heel silhouette in lateral view.

  Aligned with podiatric descriptors of calcaneal soft-tissue silhouette.

  Valid values (4)

  • narrowNarrow
  • balancedBalanced
  • broadBroad
  • haglund_prominentHaglund's prominence— Visible posterior superior calcaneal prominence; clinical Haglund deformity.

• Hallux alignment

  photo-observable

  categorical · hallux_alignment_qualitative

  Alignment of the great toe relative to the foot's longitudinal axis. Clinical hallux valgus when significantly deviated medially.

  Manchester scale for hallux valgus visual grading; Garrow AP, Papageorgiou A, Silman AJ et al. (2001). The grading of hallux valgus. The Manchester Scale. Journal of the American Podiatric Medical Association, 91(2).

  Valid values (4)

  • neutralNeutral
  • mild_valgusMild hallux valgus— Subtle medial deviation; no overlap with adjacent toes.
  • moderate_valgusModerate hallux valgus— Clear medial deviation; bunion visible.
  • severe_valgusSevere hallux valgus— Marked medial deviation; hallux overlaps or underlies second toe.

• Toenail morphology

  partly photo-observable

  categorical · toenail_qualitative

  Toenail shape and condition.

  Aligned with descriptors used in dermatology and podiatry literature.

  Valid values (5)

  • normalNormal
  • groomed_pedicuredGroomed / pedicured— Visible nail-care; native shape may not be directly observable.
  • thickenedThickened— Onychogryphosis or age-related thickening.
  • discoloredDiscolored— Onychomycosis or other discoloration visible.
  • not_visibleNot visible